Why I have no favorite programming language

TL;DR – because for me there is no good programming language.

I’m doing mostly systems engineering tasks. I manage resources in Cloud and on Linux machines mostly. I can almost hear your neurons firing half a dozen names of programming languages. I do realize that they are used by many people for systems engineering tasks:

  • Go
  • Python
  • Ruby
  • Perl
  • bash

The purpose of this post is not to diminish the value of these languages; the purpose is to share why I don’t want to use any of the languages above when I write one of my systems-engineering-task scripts. My hope is that if my points resonate with you, the reader, you might want to help spread the word about or even help with my suggested solution described towards the end.

man-2756206_640

So let’s go over and see why I don’t pick one of the languages:

Why not language X?

All languages

  • Missing smart handling of exit codes of external processes. Example in bash: if test -f my_file (file is not there, exit code 1) vs if test --f my_file (syntax error, exit code 2). If you don’t spot the syntax error with your eyes, everything behaves as if the file does not exist.
  • Missing declarative primitives libraries (for Cloud resources and local resources such as files and users). Correction: maybe found one, in Perl – (R)?ex ; unfortunately it’s not clear from the documentation how close it is to my ideas.

All languages except bash

  • Inconvenient/verbose work with files and processes. Yes, there are libraries for that but there is no syntax for that, which would be much more convenient. Never seen something that could compare to my_process > my_file or echo my_flag > my_file .

Go

  • Compiled
  • Error handling is a must. When I write a small script, it’s more important for me for it to be concise than to handle all possible failures; in many cases I prefer an exception over twice-the-size script. I do understand how mandatory and explicit error handling can be a good thing for larger programs or programs with greater stability requirements.
  • Dependencies problem seem to be unresolved issue

Python

  • Functional programming is second level citizen. In particular list/dictionary comprehension is the Pythonic way while I prefer map and filter. Yes, that’s probably one of the features that makes Python easier to learn and suggested first language. Not everything that’s optimized for beginners must be good for more experienced users. It’s OK.
  • Mixed feelings about array[slice:syntax] . It’s helpful but slice:syntax is only applicable inside [ ] , in other places you must use slice(...) function to create the same slice object

Ruby and Perl

  • The Sigils syntax does not resonate with me.

Ruby

I can’t put my finger on something specific but Ruby does not feel right for me.

Perl

  • Contexts and automatic flattening of lists in some cases make the language more complicated than it should.
  • Object orientation is an afterthought.
  • Functions that return success status. I prefer exceptions. Not the default behaviour in Perl but an afterthought: autodie.
  • Overall syntax feeling (strictly matter of personal taste).

bash

Note that bash was created in a world that was vastly different from the world today: different needs, tasks, languages to take inspiration from.

  • Missing data structures (flat arrays and hashes is not nearly enough). jq is a workaround, not a solution in my eyes.
  • Awkward error handling with default of ignoring the errors completely (proved to be bad idea)
  • Expansion of undefined variable to empty string (proved to be bad idea)
  • -e ,  -u and other action at a distance options.
  • Unchecked facts but my feelings:
    • When bash was created, it was not assumed that bash will be used for any complex scripting.
    • bash was never “designed” as a language, started with simple commands execution and other features were just bolted on as time goes by while complete redesign and rewrite were off the table, presumably for compatibility.
  • Syntax
  • No widely used libraries (except few for init scripts) and no central code repository to search for modules (Correct me if I’m wrong here. I haven’t heard of these).

My suggested solution

I would like to fill the gap. We have systems-engineering-tasks oriented language: bash. We have quite a few modern programming languages. What we don’t have is a language that is both modern and systems-engineering-tasks oriented. That’s exactly what I’m working on: Next Generation Shell. NGS is a fully fledged programming language with domain specific syntax and features. NGS tries to avoid the issues listed above.

Expected questions and my answers

People work with existing languages and tools. Why do you need something else?

  • I assume I have lower bullshit tolerance than many others. Some people might consider it to be normal to build more and more workarounds (especially around anemic DSLs) where I say “fuck this tool, I would already finish the task without it (preferably using appropriate scripting language)”. I don’t blame other people for understandable desire to work with “standard” tools. I think it’s not worth it when the solutions become too convoluted.
  • I am technically able to write a new programming language that solves my problems better than other languages.

Another programming language? Really? We have plenty already.

  • I would like to remind you that most of the programming languages were born out of dissatisfaction with existing ones.
  • Do you assume that we are at global maximum regarding the languages that we have and no better language can be made?

Feedback

Would you use NGS? Which features it must have? What’s the best way to ease the adoption? Please comment here, on Reddit (/r/bash , /r/ProgrammingLanguages) or on Hacker News.


Update: following feedback roughly of the form “Yes, I get that but many Ops tasks are done using configuration management tools and tools like CloudFormation and Terraform. How NGS compares to these tools” – there will be a blog post comparing NGS to the mentioned tools. Stay tuned!


Have a nice day!

Technology Prevention

Part of my job is to prevent usage of technologies. This sounds so uncool, I know. Do you want to increase the chance of success of your organization? You must prevent technologies. There are lots of technologies out there. Most of the technologies are not relevant to your situation. It is cool to build a spaceship, but do you need one?

Problem

Growth of a startup S that makes technology/product X is more important than whether or not there is a match between X and your use case. S generally doesn’t care whether your startup will succeed or fail because you used X. There is no immediate economical incentive for S to be honest. In short, S f*cks you over for money.

my-profit-fuck-you

 

As a consequence, a distorted picture of reality is presented to you:

  • The world is full of marketing bullshit. It is similar to psychological warfare, as noted in a post about 10gen marketing strategies.
  • Chunks of this bullshit are masked as engineering blogs.
  • Half truths are presented, such as company Blah uses X. They might be using it but for what? Is that in the core of their business or in some side project?
  • Vocal advocates of X all over (gaining directly or indirectly from you using X)

Solution

  • Remember that your aim is to succeed as a company and the aim of S is also to succeed. The correlation does not have to exist, and when it exists it does not have to be positive.
  • Start with problems that you have and find the tools for solving them, not the other way around.
  • Consider peoples’ motives when they write about tool X. Will they benefit from widespread adoption of X (consultants, employees of the make of X, people affected by investors of the company behind X)? Will they look bad if they negatively review X, even for specific use case?
  • Looking at a tool, assume it’s the wrong one for your use case and then prove this statement wrong.
  • All people must at least be aware of cost-benefit analysis. In many cases it’s actually very simple. Zero to minuscule benefit and high adoption/migration cost.
  • Take top 10 latest-shiny-cool technologies. If you are a small startup, chances are that you need zero to two of them. (Not counting the Cloud as new).
  • Using latest-shiny-cool technology to attract employees is not the right thing to do. You will probably attract employees that will always want to switch to the latest technology. Maybe they will leave for another company that starts using the next latest-shiny-cool and you don’t.

See also: Prove your tool is the right choice


Have a nice weekend!

NGS unique features – Argv command line arguments builder

Background: what is NGS?

NGS LOGO

NGS, the Next Generation Shell is a (work in progress) shell and a programming language built ground up for systems engineering tasks. You can think of it as bash that’s designed today: sane syntax, data structures, functional programming, extensibility, cloud in mind, declarative primitives.

What’s the problem with constructing command line arguments?

The problem affects only more “advanced” cases of constructing command line arguments when some arguments might or might not be present. Let’s consider this example:

# Made-up syntax, resembling NGS
args = []
if 'Subnets' in props {
  args += '--subnets'
  args += props['Subnets']
}
if ... {
  args += ...
}
if ... {
  args += ...
}
...
aws elb create-load-balancer ... $args

Wouldn’t it be cleaner to get rid of all the ifs? … and what happens if props['Subnets'] is an empty array?

How Argv facility in NGS solves the problem?

Argv is a result of factoring out the common code bits involved in constructing command line arguments. The ifs above were also factored out. They are now in Argv.

Let’s look at usage example (real NGS code, from AWS library)

argv = Argv({
  '--load-balancer-name': rd.anchor.name
  '--listeners': props.ListenerDescriptions.encode_json()
  '--subnets': rd.opt_prop('Subnets', props).map(only(ResDef, ids))
})
rd.run('create ELB', %(aws elb create-load-balancer $*argv))

The important points here are:

  1. Argv is a function with a single parameter which must be of type Hash (also called “dictionary” in some languages)
  2. The keys of the Hash are switches’ names (--load-balancer-name, --listeners, --subnets)
  3. The values of the Hash are values for the switches

The “if” that decides whether a switch is present in the resulting argv is inside Argv implementation and your code is clean of it. The values of the Hash are considered when Argv decides whether a switch should be present. null, empty array and instances of type EmptyBox are considered by Argv as missing values and it discards the switch. For convenience, instances of type FullBox are unboxed when constructing the result of Argv.

The Argv facility is yet another point among others that shows why NGS and systems engineering tasks are best fit.


Have a nice weekend!

 

Why Next Generation Shell?

Background

I’m a systems engineer. The job that I’m doing is also called system, SRE, DevOps, production engineer, etc. I define my job as everything between “It works on my machine” of a developer and real life. Common tasks are setting up and maintaining cloud-based infrastructure: networking, compute, databases and other services. Other common tasks are setting up, configuring and maintaining everything inside a VM: disks+mounts, packages, configuration files, users, services. Additional aspects include monitoring, logging and graphing.

The problem

If we take specifically systems engineering tasks such as running a VM instance in a cloud, installing and running programs on a server and modifying configuration files, typical scripting (when no special tools are used) is done in either bash or Python/Ruby/Perl/Go.

Bash

The advantage of bash is that bash is domain specific. It is convenient for running external programs and files manipulation.

# Count lines in all *.c files in this directory and below
wc -l $(find . -name '*.c')

# Make sure my_file has the line my_content
echo my_content >my_file

# Run a process and capture the output
out=$(my_process)

The disadvantage of bash is horrible syntax, pitfalls everywhere, awkward error handling and many features one would expect from a programming language (such as data structures, named functions parameters, etc) are missing.

# Inconsistent, awkward syntax,
# result of keeping backwards compatibility
if something;    then ... fi
while something; do ... done

# Can remove / if MY_DIR is not defined
# unless in "set -u" mode
rm -rf "$MY_DIR/"

# Removes files "a" and "b" instead of "a b"
myfile="a b"
rm $myfile

# Silently ignores the error unless in "set -e" mode
my_script

# Function parameters can't be named, they are
# in $1, $2, ... or in $@ and $*
myfunc() {
  FILE="$1"
  OPTION_TO_ENABLE="$2"
  ...
}

Leave bash alone, it was not intended for programming, don’t do anything in bash, just use external programs for everything.

What do you observe? Is it or is it not used as a programming language in real life?

General-Purpose programming languages

Python/Ruby/Perl/Go are general-purpose programming languages.

The advantage of general-purpose programming languages is in their power, better syntax, ability to handle arbitrary data structures.

orig = [1,2,3]
doubled = [x*2 for x in orig]

The disadvantage of general-purpose programming languages is that they are not and can not be as convenient for systems engineering tasks because they are not focusing on this particular aspect of programming (in contrast to bash and other shells for example).

# Write whole file - too verbose
f = open('myfile', 'w+')
f.write('mycontent')
f.close()

# Run a process and capture the output
# https://docs.python.org/3.5/library/subprocess.html
proc = subprocess.Popen(...)
try:
    outs, errs = proc.communicate(timeout=15)
except TimeoutExpired:
    proc.kill()
    outs, errs = proc.communicate()

Summary

My conclusion is that there is no handy language for systems engineering tasks. On one hand there is bash that is domain specific but is not a good programming language and does not cover today’s needs, on the other hand there are general-purpose programming languages which do not specialize on this kinds of tasks.

You can use Puppet, Chef, Ansible, Terraform, CloudFormation, Capistrano and many other tools for common systems engineering tasks. What if your task is not covered by existing tools? Maybe one-off? Maybe a case where using one of the existing tools is not an optimal solution? You would like to write a script, right? In that case, your life sucks because scripting sucks. That’s because there is no convenient language and libraries to get systems engineering tasks done with minimal friction and effort.

Solution

I suggest, creating a new programming language (with a shell) which is domain specific, as bash, and which incorporates important features of general-purpose programming languages: data structures, exceptions, types, multiple dispatch.

My way of looking at it: imagine that bash was created today, taking into account today’s reality and things that became clear with time. Some of them are:

  • The shell is used as a programming language.
  • A system is usually a set of VMs and APIs, not a single machine.
  • Most APIs return JSON so data structures are needed as multiple jq calls are not convenient.
  • Silently ignoring errors proved to be bad strategy (hence set -e switch which tries to solve the problem).
  • Silently substituting undefined variables with empty strings proved to be bad strategy (hence set -u switch).
  • Expanding $x into multiple arguments proved to be error prone.
  • Syntax matters.
  • History entries without context have limited usefulness (cd $DIR for example: what was the current directory before cd and what was in $DIR ?)
  • UX
    • Spitting lots of text to a terminal is useless as it can not be processed by a human.
    • Feedback is important.
      • Exit code should be displayed by default.
      • An effort should be made to display status and progress of a process.
      • Ideally, something like pv should be integrated into the shell.

I’m not only suggesting the solution I’ve just described. I’m working on it. Please give it a try and/or join to help developing it: NGS – Next Generation Shell.

NGS LOGO

# Make sure my_file has the line my_content
echo my_content >my_file

# Run a process and capture the output
out=`my_process`

# Get process handle (used to access output, exit code, killing)
p=$(my_process)

# Get process output and parse it, getting structured data
amis=``aws ec2 describe-images --owner self``
echo(amis.len()) # number of amis, not lines in output

# Functional programming support
orig = [1,2,3]
doubled = orig.map(X*2)

# Function parameters can be named, have default values, etc
F myfunc(a,b=1,*args,**kwargs) {
  ...
}

# Create AWS VPC and Gateway (idempotent)
NGS_BUILD_CIDR = '192.168.120.0/24'
NGS_BUILD_TAGS = {'Name': 'ngs-build'}
vpc = AWS::Vpc(NGS_BUILD_TAGS).converge(CidrBlock=NGS_BUILD_CIDR, Tags=NGS_BUILD_TAGS)
gw  = AWS::Igw(Attachments=[{'VpcId': vpc}]).converge(Tags=NGS_BUILD_TAGS)

I don’t think scripting is the right approach.

It really depends on the task, constraints, your approach and available alternative solutions. I expect that situations needing scripting will be with us for a while.

Another programming language? Really? Why the world needs yet another programming language?

I agree that creating a new language needs justification because the effort that goes into creating a language and learning a language is considerable. Productivity gains of using the new language must outweigh the effort of learning and switching.

NGS creation is justified in exactly the same way as many other languages were justified: dissatisfaction with all existing programming languages when trying to solve specific problem or a set of similar problems. In case of NGS the dissatisfaction is specifically how existing programming languages address the systems engineering tasks niche. NGS addresses this particular niche with a unique combination of features and trade offs. Productivity of using NGS comes from best match between the tool and the problems being solved.

Yet another shell? We have plenty already but they all have serious adoption problems.

NGS will be implementing ideas which are not present in other shells. Hopefully, the advantages will be worthy enough to justify switching.

I’ll be just fine with bash/Python/Ruby/Perl/Go

You will. The decision to learn and use a new language depends on your circumstances: how many systems engineering tasks you are doing, how much you suffer, how much easier the tasks will become with NGS, how easily this can be done in your company / on your project and whether you are willing to take the risk.

You could just write a shell based on Ruby or Python or whatever, leveraging all the time and effort invested in existing language.

I could and I didn’t. Someone else did it for Python and for Scala (take a look, these are interesting projects).

  • I don’t think it’s the right solution to stretch existing language to become something else.
  • NGS has features that can not be implemented in a straightforward way as a library: special syntaxes for common tasks, multiple dispatch.

One could just write a library for Python or Ruby or whatever happens to be his/her favorite programming language, leveraging all the time and effort already invested in existing language.

In order to be similar to NGS, one would not only have to build a library but also change language syntax. I personally know only two languages that can do that: Lisp (using reader macros) and Perl6 (using grammar facility). These are general-purpose programming languages. Turning them into something NGS-like will be a significant effort, which I don’t think is justified.

PowerShell appears to be similar to what you describe here.

Note that I have very limited experience with PowerShell. The only aspect I definitely like is consistent usage of the $ sigil.

  • It’s probably a matter of taste and what you are accustomed to but I like NGS’ syntax more. PowerShell is pretty verbose.
  • DSC appears to be focused on resources inside a server/VM. NGS plans similar functionality. Meanwhile, NGS uses this approach in the AWS library: vpc = AWS::Vpc(NGS_BUILD_TAGS).converge(CidrBlock=NGS_BUILD_CIDR, Tags=NGS_BUILD_TAGS)

There are libraries for Python that make systems engineering tasks easier.

Right, sh for example. Such solution can’t be used as shell, it just improves the experience of calling external program from Python.


Was this post convincing? Anything is missing to convince you personally? Let me know!

Have a nice day!

Please don’t use Puppet

Thinking process behind choosing a tool

Thinking process behind choosing a tool does not get the attention it deserves. While there are many discussions of the form tool X vs tool Y, there is very little discussion of how one should choose between tools or in presumable absence of alternatives, whether one should use the only candidate, tool X. This post will cover few things to keep in mind when selecting a tool by highlighting few common problems and fallacies. Puppet will be used as an example tool for consideration.

Focusing on positive parts only

When considering a product or a tool, too often positive aspects are overestimated and negative aspects that influence TCO (Total Cost of Ownership) are underestimated or neglected. There are several cognitive biases and logical fallacies involved. Cognitive biases and logical fallacies can be avoided to some extent just by being aware. I will be referring to these through the post to help you, the reader, become more aware of your thought process which will hopefully improve it and consequently the process of decision making on your part.

Marketing pushes to see the positive

We all know that marketing focuses on positive aspects of a product and neglects to mention downsides. This is specifically mentioned in “False advertising” article under “Omitting information”.

For example, the fact that it’s not convenient to manage Puppet modules (proof: existence of a tool to do just that) will not appear in marketing materials. You might think that the existence of Librarian-puppet is on the contrary, makes management of these modules easier. It does but it also brings more complexity to the system. New problems and bugs instead of inhuman manual management of modules.

This post will focus on the negative

While there is more than enough focus on positive aspects of products, this post will be highlighting the negative aspects in order to strike some balance. There is plenty of marketing materials but it’s harder to find a list of problems that you only discover when you are neck-deep into the tool/product. These problems will be listed here. Note that this can not be exhaustive list because different situations reveal different problems and this post is only based on experience of several of my friends and mine.

Listing the problems of a tool touches Availability heuristic cognitive bias: the easier you recall something the more “important” it is. You are bombarded by marketing materials which are all positive. When considering a tool, your natural flow of thought is “How easily can I remember positive sides of the tool?” and it’s easy, because you were probably brainwashed already by how good the tool is. Then “How easily can I remember negative sides of the tool?” is much harder. This is not the kind of information that will be pushed to you by the people behind the tool, they have no interest in doing so. Their money goes to advertise how good the tool is, not how bad it is. You can balance your rosy impressions of any tool or product with looking at GitHub issues, digging StackOverflow for the downsides, or reading posts like this one.

Please, assume that X is the wrong tool for your needs.

As opposed to “yeah, looks good, let’s use it”, this approach leads to more thoughtful tool selection process. Please read Prove your tool is the right choice.

“Everybody uses X”

“Everybody uses X” thought might have been planted in your brain by marketing efforts. Please analyze the source of that thought carefully. Maybe you have heard from some of your friends and/or colleagues about the product and made a generalization? Maybe people are just stuck with it? Maybe that’s what they know? Did you search for alternatives? Did you try to disprove “Everybody uses X”?

“Everybody uses X, therefore it’s good”

Whether this thought was planted by marketing or not, no, there is no logical connection between the first and the second clauses.

If a lot of people use something, it becomes better as there is more feedback and contributors. It is often implied that therefore X is good. Improvement over time or with user base does not mean X is good enough for any particular use right now.

Did you communicate with the people that use X? Did they tell you it was a good decision? Beware of Choice-supportive bias when you talk to them. Which alternatives did they consider? Are they able to articulate downsides? Every solution has downsides, being able to recognize these increases credibility of the opinion about X.

“Everybody uses X, we should use X”

Yes, if you consider the value of “then we can blog about it and be part of the hype, possibly getting some traction and traffic”. This might have some estimated value which should be weighted against the cost incurred by choosing otherwise unneeded or inferior tool or technology. You can point your bosses to this paragraph, along with your estimation of the costs of using tool X vs better alternatives (which might be just not using it and coding yourself the needed functionality for example, the comparison is valid for both X vs Y and X vs without X).

No, “We should use X” does not logically follow from “Everybody uses X”. Beware of conformity bias.

“Company C uses X”

This piece of information, when served by vendor of X implies that company C knows better and you should use X too.

Company C is big and respectable company with smart engineers. The vendor of X will gladly list big and reputable companies that use X. That’s the use of “Argument from authority”.

Again, there is no straight logical path between “C uses X” and “we should use X too”.

Chances are that company C is vastly different from your company and their circumstances and situation are different from yours.

Company C can also make mistakes. You are unlikely to see a blog post from vendor of X that is titled “Company C realized their mistake and migrated from X”.

Claims of success with tool X

Treat claims of successful usage of tool X with caution. Searching quickly for “measuring project success” reveals the following dimensions to be looked at when estimating a success of a project:

  • Cost
  • Scope
  • Quality
  • Time
  • Team satisfaction
  • Customer satisfaction

The claims of successful usage of tool X carry almost no information regarding what really happens. “We are using Puppet successfully” might mean (when taken to extreme) that for 100 servers and one deploy per day the following applies:

  • Cost: There is dedicated team of five costly operations people that work just on Puppet because it’s complex.
  • Scope: Puppet covers 80% of the needs, this might be the only dimension looked into when claiming a success.
  • Quality, Team satisfaction: This team is constantly cursing because of bugs, modules or Puppet upgrades issues such as Upgrade to puppet-mysql 3.6.0 Broke My Manifest (fixed in just two months!) or puppet 4.5.0 has introduced a internal version of dig, that is not compatible to stdlib’s version oopsie.

    Enjoy the list of regression bugs. It’s hard to blame Puppet developers for these bugs because these kinds of issues are natural for projects of this size and complexity. I suggest that creating your own domain-specific language, which is not a programming language for a configuration management tool is a bad idea. I’ll elaborate about this point in a bit, in the “Puppet DSL” section.

  • Time: Took 6 moths of the above team to implement Puppet. Unpredictable time to implement any feature because of complexity and unexpected bugs along the way.
  • Customer satisfaction: Given all of the above it’s hard to believe in any kind of satisfaction with what’s going on.

It’s also worth to keep in mind that any shown success, real success, does not mean that same solution will be equally applicable to your situation, because it’s almost certainty different on one or more dimensions: time, budget, scope (problem you are solving), skills, requirements.

“But X also provides feature F”

I am sure that the advertisements will mention all the important features as well as “cool” features. Do you really need F?

When choosing a tool the thought “But X also provides feature F” might be dangerous if F is not something you immediately need. One might think that F might be needed later. This might be the case but what are the odds, what’s the value of F to you, how much will it cost to implement using another tool or write yourself? Also, consider the “horizon”. If you might need feature F in 3 years, in many situations this should be plainly ignored. In 3 years there might be another tool for F or you might switch from X to something else for other reasons by then.

Suppose there is another tool X2 which is alternative to X. X2 does not provide F but it’s estimated TCO over a year is 50% less than F. You should consider the costs because it might be that X2 for the first year and then switching to X, including the switching costs can be cheaper.

Putting tools before needs

“So, there is new trendy hypy tool X. How can we use it?” is typically a bad start. At the very least it should be “So, there is new trendy hypy tool. Do we have any problems where X would be a better alternative?”

Ideally the approach would be “We have problem P, which alternative solutions do we have?”. P might be some inefficiency or desired functionality. Solutions, once again, do not have to mean existing tools.

Puppet – the good parts

I will quickly go over a few good parts because I want this post at least to try to be objective.

Convergence

Convergence is an approach that says one should define the desired state, not the steps to be taken to get there. The steps are abstracted away and on each run the system will try to achieve the desired state as closely as possible.

I do agree that declaring a resource such as file, user, package or service and it’s desired state is a good approach. It’s concise and it’s usually simpler than specifying the operations that would lead to the desired state, like regular scripts do. This idea manifests in many other tools too: Chef, Ansible, CloudFormation, Terraform.

Appropriate in some situations

  • Think about a startup where someone does part time systems engineering job, not a professional. As Guy Egozy pointed out, there are situations such as startups with limited resources and basic needs where using a configuration management tools might make more sense than in other situations.
  • Urgent demo with all defaults if you have a good control of the tool and you know that you need some very specific functionality, say wordpress+mysql demo tomorrow, it is probably worth to prepare the demo with Puppet or Chef. There is still a danger of course that the module you were using a month ago have now changed and you need to invest additional time to make things work. Or maybe the module is just broken now.

Multiple platforms support

In my experience the chances that you will be running same applications on say Windows and Linux are pretty slim. The overlap of installed software on different platforms is likely to be infrastructure tooling only (monitoring, graphing, logging). Is it really worth the price?

Puppet DSL

Puppet class

Puppet DSL has a concept of “class” which has nothing to do with classes in programming languages. It least in retrospective it was not such a good idea, especially when considering operations guys trying to explain about Puppet classes to developers.

Limited DSL limitations 🙂

Acknowledged as a problem by facts

Limitations of DSL in my opinion were acknowledged by actions taken by Puppet’s developers and contributors:

Limited DSL is not a great idea!

I do understand why limited DSL can be aesthetically and mathematically appealing. The problem here is that life is more complex than limited DSL. What could be 10 lines of real code turns into 50 lines of ugly copy+paste and/or hacks around the DSL limitations.

It sounds reasonable that at the time when CFengine and Puppet were created there were not enough examples of shortcomings of limited DSLs and their clashes with real life. Today we have more:

  • Puppet – DSL failure admitted by actions, as discussed above.
  • Ansiblejust looks bad . Some features look like they were torn from a programming language and forced into YAML.
  • Terraform – often generated because well … life. This one is more of a configuration language by design. This approach has pros and cons when applied to infrastructure.
  • CloudFormation – 99% configuration format and 1% language, that’s why it’s generated for all except trivial cases. You do have the alternative of not generating CloudFormation input file but provide custom resources which use AWS Lambda functions instead. They will do some of the work. While this fits CloudFormation model perfectly, and makes CloudFormation much more powerful, I would really prefer a script over inversion of control and additional AWS service (Lambda) which I have to use – one more thing that can go wrong or just be unavailable when needed the most.

I do not agree that Terraform should be limited the way it is, but in my opinion, Terraform and CloudFormation are more legitimately limited while Puppet and Ansible are just bad design. This limitation by design causes complex workarounds which are costly and sometimes fragile, not to mention mental well being of the systems engineers that are working with Puppet.

We can all stop now creating domain specific languages for configuration management which were not built on top of real programming languages. Except for a few cases, that’s a bad idea. We can admit it instead of perpetuating the wishful thinking that the reality is simple and limited DSL can deal with it somehow.

Puppet modules

Dependencies between Puppet modules

Plainly headache. Modules have dependencies on other modules and so on. Finding compatible modules’ versions is a hard problem. That’s why we have Librarian-puppet. As I mentioned above, it has it’s own issues.

There are also issues that Librarian-puppet can not solve, which are inherent to system of this scale, complexity and number of contributors. Let’s say you have module APP1 that depends on module LIB and module APP2 that also depends on LIB. Pinning version of module LIB because APP1 has a bug can prevent you from upgrading module APP2 which in newer versions depends on newer LIB. This is not imaginary scenario but real life experience.

Breakage of Puppet modules

Another aspect is that in this complex environment it’s somewhere between hard and impossible for any module maintainer to make sure his/her changes do not break anything. Therefore, they do break:

Popular community modules deal with so many cases and operating systems that breakage of some functionality is inevitable.

Community modules

There is this idea that is kind of in the air: “you have community modules for everything, if you are not using them you are incompetent and wasting your time and money”.

This could come from 3 sources:

  • Marketing
  • People that use community modules for simple cases and they work fine
  • People that underestimate the amount of maintenance work required to make community modules work for your particular case.

The feedback that I’ve got several times from different sources is that if you are doing anything serious with your configuration management tool, you should write your own modules, fitting community modules to your needs is too costly.

Graph dependencies model problems

Do you know people who think in dependency graphs? It looks like most people that I know are much more comfortable thinking about sequence of items or operations to perform in most cases. Thinking about dependency graphs such as about packages’ versions compatibility usually comes with recognizable significant mental effort, often with curses.

Puppet team admitted (again, by actions) this is a problem and introduced ordering configuration and made “manifest” ordering the default at some point. Note that this ordering is only for resources without explicit dependencies and within one manifest.

Graphs are somewhat implicit. This causes surprise and consequential WTFs. Messages about dependencies errors are not easily understood.

Marketing

  • Puppet usage is compared to manual performance of the same tasks – “Getting rid of the manual deployments”. This is clearly a marketing trick: comparing your tool to the worst possible alternative, not other tools which are similar to yours.
  • Puppet is compared to bash scripts. Why not Python or Ruby?
  • “Automate!” is all over Puppet site. Implies that Puppet is a good automation tool.
  • Top 5 success stories / case studies use Puppet Enterprise? Coincidence? I think not 🙂

Thanks

Many thanks for guidance to Konstantin Nazarov (@racktear). We met at DevOpsDays Moscow 2017 where he offered free guidance lessons for improving speech and writing skills. In reality, lessons also include productivity tips which help me a lot. Feel free to contact Konstantin, he might have a free weekly slot for you.


Have a productive career!

About declarative frameworks and tools

This post is a reply to “just use Terraform” recommendation I’ve just seen. I hope more people will benefit from my perspective if it’s posted here. There is plenty of marketing behind most of the tools I mention here. It’s all rosy, see the “Life before Puppet” video. Let’s balance this marketing bullshit a bit.

Think twice before using declarative framework/tool

Terraform, CloudFormation, Puppet, Chef as any other declarative frameworks/tools take control away from you. They work fine for “hello world” examples. Then there is life where you need something these frameworks did not anticipate and you are sorry you have not coded everything yourself from the start. Now you are stuck with these tools and you will be paying for it in your time and money. Working around limitations of such tools is a pain.

I am using CloudFormation and have used Puppet and Chef in the past. These tools do have their place. In my opinion it’s a very limited set of scenarios. Terraform, CloudFormation, Puppet and Chef are used much more widely than they should be.

These tools have some value but too often people neglect the cost which in many cases outweighs the value. Most of the cost comes from inflexibility. Terraform and CloudFormation are so limited that people frequently use another tool for generating these. That adds another bit to the cost.

I’m hearing frequently from a friend (sorry, can’t name him) how much they suffer from Terraform’s inflexibility. Inflexibility can not be fixed because it’s a declarative framework. Unfortunately they are so invested in Terraform that they will continue to spend hundreds of hours to fight it. Chef is causing trouble there too, community Cookbooks proved to be a mismatch for the needs and sanity of the engineers there.

… and there is this gem

A key component of every successful Puppet implementation is access to a knowledgeable support team

That’s from https://puppet.com/support-services/customer-support/support-plans

Are you sure you want to use Puppet? Apparently you can’t do it well without their support… Just saying…

Is one of these tools right for you?

Regular considerations for choosing a tool apply. See my older post “Prove your tool is the right choice“.

Expected replies and my replies to those

You don’t get it.

OK

You don’t understand these tools.

OK

You are not using these tools right / as intended.

OK

Are you crazy? You want to code everything yourself?

Let’s take it to the extreme: no new code should be written. No libraries, no frameworks. Because everything already exists. Sounds about right.

People smarter than you have figured it all out, use their tools

Smarter people don’t always produce better solutions or solutions that fit your use case. Most of the time smart people will produce smart solutions… and then there are people that don’t usually think in graphs and are really puzzled when debugging Puppet cyclic dependency errors for example.

Most of the code you need is already written, don’t waste time and money, use it! Community Cookbooks and modules are great!

This is marketing bullshit. Don’t buy it! It’s often more expensive to adopt a code that does not meet your exact needs and is much more complex that you need (because it should support multiple platforms and use cases) than to write your own. I have seen suffering followed by usage of community Cookbooks/modules followed by in-house rewrite or fork.

Don’t you care about the next guy? Work with standard tools!

Let’s do some math. Team of two works for a year. They are (very modest estimation) 10% more productive because they have coded whatever they needed and were not fighting with the tools. Even when wrongfully assuming that custom solution is harder to understand for the 3rd guy that joined the team after one year, how much is it harder? Is it more than 300 hours harder?

Update following responses on Reddit

2017-04-28

2 totally different toolsets – infrastructure orchestration (Terraform, Cloudformation), and Configuration Management (Puppet, Chef)… — (/u/absdevops)

Yes. What is common to all these tools is declarative style and their usage: these tools are typically run using CLI.

All these tools have three axes that I consider:

  1. “Input” axis: What’s the input of these tools?
    1. Configuration format
    2. Half-baked programming language that was probably never indented to be a programming language
    3. Real programming language
  2. “Calling” axis: framework vs library (typical usage)
  3. “TCO” axis: TCO vs other solutions, especially vs the other solution that is always available – code the subset of the functionality that you need yourself

I’d like to make sure that it’s clear that the tools mentioned in this article have different positions on the 3 axes and are not equal in the value they provide you in your specific situation.

The main point of the article is that while these tools differ on axes 1 and 3, they are all limiting because conceptually, they are all frameworks. You pass your execution into the tool and it does a lot. Here is where you loose your flexibility as opposed to using a library. You have relatively little control of what happens inside the tool.

I must strongly disagree with Terraform being put in the list – its a great base tool with limitations that can be worked around. — (/u/absdevops)

I don’t want to work around limitations. It seems to be the norm for these tools. I’d rather have a library that misses parts that I’d code myself. Working around limitations in my opinion is generally much worse than missing functionality (depends on specific circumstances of course).

Regarding inflexibility – it’s probably the most flexible tool of the bunch — (/u/absdevops)

Please note we are still comparing between the tools that all use limiting paradigm: frameworks

I will also duel anyone to the death for preference of Cloudformation syntax to Terraform — (/u/absdevops)

We are talking about the “Input” axis I mentioned above. Yes, Terraform syntax apart from being more aesthetically pleasing is somewhat closer to “Half-baked programming language that was probably never indented to be a programming language” while CloudFormation is somewhat closer to “Configuration format”.

I totally disagree with points made about having to generate Terraform manifests. … generate what you need specifically, and hand it off to Terraform, much like making an API call to a library. — /u/SlinkyAvenger

There is a huge difference in the amount of work done by typical API call and what these tools do once you call them. With more granular API calls you decide if and when you do specific calls and what do you do in between the calls – it’s much more flexible.

I’m also a big proponent of Puppet — /u/SlinkyAvenger

One of the low value tools from my perspective. I’ll explain. On the “Input” axis, it’s half-baked programming language. Better than configuration file but still loses to Chef for example. On the “TCO” access, I really think that Puppet and Chef are not good alternatives to custom scripts in most cases. Scripts by the way also win on the “Calling” axis, which means flexibility.

I’d really like to hear what you’re honestly going back to puppet support for. — /u/neoghostz

We don’t. When we suffered while working with Puppet, we knew that support will not solve our problems. Some crappy community modules can not be solved by support. Breakage on modules versions updates – same. Librarian, more complexity on top of complexity – same. The above quote about support (“A key component of every successful Puppet implementation is access to a knowledgeable support team”) was just to highlight that guys at Puppet think people can’t use it without support. This is just a humorous point and not really important.

What is the point of this article? It basically dumps on Terraform, CF, Puppet, Chef, etc., but offers no actual criticism (other than a vague ‘it takes away control’ statement) or, perhaps more importantly, alternatives. — /u/cryonine

The point is that all these tools would have been better if they would be implemented as libraries on top of real programming languages, where you call the parts that you need instead of one “do everything” call.

With the exception of Chef, these tools use either configuration files as input or configuration-file-almost-a-programming-language format. It’s always the same path:

  1. We need small limited DSL it’s so academically beautiful, we can prove theorems about this.
  2. Oh wait, there are real world scenarios where it’s not enough, damn these complaining engineers.
  3. Let’s add stdlib
  4. Let’s add proper loops
  5. Now we have a half-baked programming language.

Elaborating on taking control away from you. You get convoluted things like this:

Alternatives

For Puppet and Chef, I have not seen a single system where my estimated TCO of these tools would be better than a bunch of idempotent modular bash scripts which I use. It did not take much time to write these. Some Python is used for configuration generation (json / jinja templates + environment data).

With Cloudformation and Terraform it’s not that simple. I’m mostly amazed that nobody does libraries which would just provide declarative primitives, not frameworks where you feed everything you need via one call. I am working on one but it is really strange for me that I haven’t heard already about such library for Python or Ruby.

Terraform … vastly superior to any other alternate out there — /u/cryonine

Not sure I agree 100% because it depends on situation but I can imagine many situations where it’s correct. The important thing here is that I think that all current alternatives are not so good.

How is it wrongful to assume that a custom solution is harder to understand? That’s completely accurate. — /u/cryonine

Custom solution is simpler. Do you really need documentation for 19 lines of bash code that installs Nginx and another 29 that do a restart that handles leaking file descriptors? You will definitely need documentation of 2000+ lines of Chef cookbook or Puppet module that install Nginx and … oh wait… how do I reload Nginx and then conditionally (if enough file descriptors leaked) restart it? Time to dive in 🙂

I do imagine how custom solution can be complicated (read harder to maintain and higher TCO) if done by unprofessional people. In some cases it might be better for them to use a framework. On the other hand, they might stuck when trying to do something advanced with the framework. Really depends on the situation.

While “use standard tools” generally sounds right, I have seen too much convoluted solutions using “standard tools” because of the inflexibility. People were trying to work around the limitations. Comparing top-down execution of simple script to workarounds for these tools, it’s much simpler to wrap your head around the scripts. I have recently passed one of my clients to the next guy. I have asked him how he is doing and he told me that he was happy to have simple custom solution over complex frameworks. TCO has many components. Choosing “standard tools” does not always outweigh other aspects.

 


Have a nice day and a productive life!

NGS unique features – improving NodeJS require()

Background: what is NGS?

NGS, the Next Generation Shell is a (work in progress) shell and a programming language built ground up for systems engineering tasks. You can think of it as bash that’s designed today: sane syntax, data structures, functional programming, extensibility, cloud in mind, declarative primitives.

What’s good in NodeJS’ require()

I like most of how require() works in JavaScript. I’m not talking in this post about npm, just NodeJS require() function. require() does not pollute your namespace, you just get a reference, it’s simple to use and easy to reason about.

const a = require('cool-aws-wrapper');
// Can not be done easily with AWS SDK:
a.deleteRoute53Record('testing25.example.com');

What’s there to improve in require() ?

NodeJS modules are usually fall into one of the categories:

  1. Class definition / big library that manages it’s own namespace. These usually end with module.exports = MyClass. No problem here.
  2. Group of functions or classes. These usually end with module.exports = { func1, func2, func3, ...} lists (ES6 syntax, otherwise written as module.exports =  { func1: func1, ... } ) which I think are cumbersome.

How require() and modules look in NGS?

Note that require() in NGS is work in progress and it doesn’t have much of the functionality that NodeJS provides. I just started with things that bothered me the most.

Consistent with other places in NGS, require() returns the last evaluated expression. NodeJS for example returns module.exports which you must explicitly set as the result of require().

I think of modules primary as a namespaces. Creating a namespace in NGS has a syntax: ns { ... } .

Combining require() behaviour of returning last evaluated expression and namespace syntax, typical NGS module consists of single top level expression which evaluates to a namespace. The whole module file can look like this:

ns {

  global init

  type Vpc
  type Subnet

  F init(v:Vpc) {
    ...
  }

  F _helper_func(s:Str) { ... }

  MY_CONST = 42

  F ok() {
    echo("OK")
  }

}

Let’s ignore the global for now, it’s about how methods and types’ instances creation are implemented in NGS. Anything defined inside the ns { ... } is exposed as namespace member so usage of the above module could look like this:

{
  m = require('mymodule.ngs')
  vpc = m::Vpc()
  echo(m::MY_CONST)
  m::ok()
}

As you probably guessed, the :: operator is the namespace member access operator.

There is no need to explicitly state what module/namespace exports. That’s the improvement over NodeJS’ require().

How ns works and more options for the curios

ns { … } returns a Hash

As stolen from NodeJS, the namespace syntax (ns { ... }) returns a Hash. In NodeJS, require() typically returns JavaScript Object which is close enough for the purpose of this post.

About :: operator

The namespace member access operator :: is actually a Hash key access operator. It is helpful because the regular syntax for accessing members is not always a good fit for namespaces. The regular member access syntax is dot (.) but the dot syntax is also a function call: myobj.field – is a field/key/attribute access but myobj.func() is equivalent to func(myobj). For example, m::ok() will call the ok function defined in the module, m.ok() will call the function ok in current lexical environment with m as parameter.

As a bonus, since :: is an operator, it is implemented as function call. This means you can define how :: works with types that you define and modify how :: works with existing types.

ns { … } syntax implementation

For simplicity of implementation and absence of obvious reasons against, ns { ... } syntax is just a syntactic sugar for defining anonymous function without parameters and calling it immediately. The though behind this decision was simple: “I need to implement namespaces. Let’s see where I have them already. Oh, namespaces are already implemented in functions. This is so convenient, I can use this mechanism with minimal effort”.

How ns knows what to return?

ns is mostly a syntactic hack:

  1. Inside the ns body, the first statement, before any use-supplied statements is _exports = {} which sets the local variable _exports to an empty Hash.
  2. Any assignment and function definition also set _exports["something"]. MY_CONST = 42 becomes MY_CONST = 42;  _exports["MY_CONST"] = MY_CONST;
  3. Exception to the rule above are variables and functions with names starting with underscore (_). They are not automatically added to _exports. This for example is why _exports itself is not exported.
  4. Last statement, after all user-supplied statements is _exports.

The behavior I just described looks like sane defaults to me. As we all know, the life is usually more complex than hello world examples and customizations are need. Here are two ways to customize the resulting namespace.

  1. return your_expr – since ns is just a function, you can use return at any point to return your own custom namespace.
  2. manipulate _exports however you want towards the end of ns body. For example after _exports .= filterv(Type) only types will be exported. _exports.filterk(/^pub_/) will only export symbols (keys) that have names that start with pub_ .

Improvement suggestions are welcome! Have a nice day!