paulo-ferraz-oliveira / tcp_echo_livebook.livemd

Last active August 27, 2023 21:10

TCP Echo Server using Livebook (with inputs)

TCP Echo Server using Livebook

Here's an example of a TCP Echo Server using Livebook.

Install the dependencies

Mix.install([{:ranch, "2.0.0"}])

paulo-ferraz-oliveira / gha-tool-versions.md

Last active January 8, 2024 18:42

Read .tool-versions to GitHub env. and use it in between jobs

I recently made a cross-platform GitHub action out of this (using outputs instead of environment variables) Check it out at https://github.com/paulo-ferraz-oliveira/parse-tool-versions/.

The script

In e.g. .github/parse-tool-versions.sh, do:

#!/bin/bash

paulo-ferraz-oliveira / recon_trace_format.md

Last active July 12, 2023 08:31

Shows an (Elixir) example of tracing HTTPoison's :request and extracting from the call and the return value, using Fred Hebert's recon

Tracing in Elixir with `:recon`, and `formatter`

I tend to not remember how this is done, so here goes, for easier copy-paste effect:

:recon_trace.calls(
  {_mod = HTTPoison, _fun = :request, fn ([_, _, _, _, _]) -> :return_trace end},
  _calls = 10,
  [scope: :local,
 formatter: fn (tuple) -&gt;

paulo-ferraz-oliveira / logging_decorator.md

Created May 5, 2023 13:17

Wrap a function in a "timed-performance" log decorator, using Elixir library decorator and Logger

Here's an example of how to do it.

def with_performance_log(options, body, context) do
  quote bind_quoted: [
          context: Macro.escape(context),
          options: Macro.escape(options),
          body: body
        ] do
 module = "#{context.module}"

paulo-ferraz-oliveira / elixir_fprof_profiling.md

Created May 12, 2023 16:11

Profiling in Elixir using :fprof

Something like

  def trace(ms, where) do
    Task.start(fn ->
      # making sure file is writable (otherwise it'll only crash later, after a WHILE)
      :ok = File.write(where, "")
      :ok = :fprof.stop()
      
 {:ok, _} = :fprof.start()

paulo-ferraz-oliveira / elixir_credo_duplicate_use.md

Created May 12, 2023 17:12

An Elixir Credo custom check for making sure you don't have duplicate `use`

Here's an example on how to do it.

defmodule OneUseAlone do
  use Credo.Check,
    base_priority: :high,
    category: :warning,
    explanations: [
      check: """
      Checks if `use` happens more than once in a given module

paulo-ferraz-oliveira / makefile_21.md

Last active July 20, 2024 13:35

Makefile 21st century options

Some Makefile options for the 21st century

SHELL := bash
.ONESHELL:
.SHELLFLAGS := -e -u -c -o pipefail
.DELETE_ON_ERROR:
MAKEFLAGS += --warn-undefined-variables
MAKEFLAGS += --no-builtin-rules

paulo-ferraz-oliveira / common_test_all_0.md

Created August 23, 2023 18:40

Filling your Erlang/OTP's Common Test suites' `:all/0` automatically

Common Test trickery

We can define an Erlang/OTP Common Test suite with

-module(...).

-compile([export_all, nowarn_export_all]).

all() -&gt;

paulo-ferraz-oliveira / gha_plus_rebar3_depup_schedule.md

Last active December 17, 2023 18:28

Schedule your rebar.config version updates with rebar3_depup and GitHub Actions

`rebar3_depup`-based `rebar.config` version updates

... on scheduled GitHub Actions.

How to achieve it?

workflow `.yml`

This is an example scheduled-based workflow to run a .sh at a given time of day.

paulo-ferraz-oliveira / bump_vsn.md

Created September 9, 2023 11:54

Bump a specific dep's version in mix.exs (via AST traversal)

Bump `mix.exs` dep. version

(from: jelly-beam/rebar3_ex_doc#67)

This little Gist shows how to achieve simple AST walk + update to change a module attribute, that defines a version (in the example), in mix.exs.

# up_version.exs
defmodule UpVersion do
  @mix_exs "mix.exs"

Paulo F. Oliveira paulo-ferraz-oliveira