inets:start() will automatically start the httpc service also!

https://stackoverflow.com/a/64212985/1498178

This should be profile() = default | atom() because the httpc service is automatically started with the default profile (called default) when inets is started.

See also How to get more information about error when starting Inets httpd?

https://stackoverflow.com/a/64212985/1498178

the Function-as-a-Service offering often have multiple fine-grained updateable code modules (functions) running within the same vm, which comes pretty close to the Erlang model.

then add service mesh, which in some cases can do automatic retry at the network layer, and you start to recoup some of the supervisor tree advantages a little more.

really fun article though, talking about the digital matter that is code & how we handle it. great reminder that there's much to explore. and some really great works we could be looking to.

What does this mean?

This sentence is straightforward but I only understood it just now.

rebar.config can specify the dependencies of all the applications in the umbrella project, but they are not necessarily run-time dependencies. Also, the relx example from the rebar.config above shows how to include an app/lib (in this case, recon) in the final production release, even if it is not a run-time dependency.

This guide also expands on it a paragraph below:

The Rebar3 maintainers therefore just decided to keep a clear distinction between the applications that need fetching for the project to build or run (in rebar.config), and the run-time dependencies of each OTP application (in the .app file) which may be part of the default OTP install, and would therefore not be included in rebar.config. Other build tools in the ecosystem let you achieve similar results, but they default to including everything at run-time whereas Rebar3 asks of developers to always be specific in their intent.

restart defines when a terminated child process must be restarted.

• A permanent child process is always restarted.
• A temporary child process is never restarted (even when the supervisor's restart strategy is rest_for_one or one_for_all and a sibling's death causes the temporary process to be terminated).
• A transient child process is restarted only if it terminates abnormally, that is, with another exit reason than normal, shutdown, or {shutdown,Term}. https://erlang.org/doc/man/supervisor.html

Or use the Nix package manager's nix-shell.

• https://toraritte.github.io/posts/2020-07-15-nix-shell-with-specific-path.html
• https://stackoverflow.com/a/62923700/1498178

Q1: So inet and socket are competing socket implementations then?

Q2: inets is higher level abstraction layer on top of inet? (Just as HTTP is higher level than transport protocols.)

Q3 (corollary of Q1 and Q2): inets could be then rewritten to use socket instead? (And used just like gen_tcp with the inet_backend option?)

When to use different programming languages (advice from an Amazon employee):

• Java - enterprise applications
• C# - Microsoft's spin on Java (useful in the Microsoft's ecosystem)
• Ruby - when speed is more important then legibility or debugging
• Python - same as Ruby but also for ML/AI (don't forget to use type hinting to make life a little saner)
• Go/Rust - fresh web service where latency and performance were more important than community/library support
• Haskell/Erlang - for very elegant/mathematical functional approach without a lot of business logic
• Clojure - in situation when you love Lisp (?)
• Kotlin/Scala - languages compiling to JVM bytecode (preferable over Clojure). Kotlin works with Java and has great IntelliJ support
• C - classes of applications (operating systems, language design, low-level programming and hardware)
• C++ - robotics, video games and high frequency trading where the performance gains from no garbage collection make it preferable to Java
• PHP/Hack - testing server changes without rebuilding. PHP is banned at Amazon due to security reasons, but its successor, Hack, runs a lot of Facebook and Slack's backends

We start out with the TL;DR treatise: The mnesia database is not CP, nor AP. And it cannot be CA, because CA doesn’t make any meaningful sense. In short, it is broken with respect to the CAP theorem. https://medium.com/@jlouis666/mnesia-and-cap-d2673a92850

Content-Length

Not mentioned anywhere (not even in the inets User's Guide), but Content-Length is calculated automatically if it is not provided.

See httpc_request.erl#213.

This is a pretty cool trick. So looks like a way to bypass the copying overhead is to make a function that only has constant outputs and doesn't actually compute anything.

I got here from the discord blog on how they optimized their performance and it looks like the trick is to batch messages when sending to remote nodes. Seems kinda obvious though that batching messages would improve performance.

A trick to keep in the back pocket.