From 4780f7a931c03a3f6849536ee8a89e7e6ee0572a Mon Sep 17 00:00:00 2001
From: Gonzalo <456459+grzuy@users.noreply.github.com>
Date: Mon, 30 Oct 2023 18:09:33 -0300
Subject: [PATCH] docs: explain building from source in README

---
 .github/workflows/ci.yml |  2 +-
 README.md                | 19 +++++++++++++++++++
 lib/candlex/native.ex    |  2 +-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c06aff8..c177466 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
   main:
     runs-on: ubuntu-latest
     env:
-      CANDLE_BUILD: true
+      NATIVE_BUILD: true
     strategy:
       fail-fast: false
       matrix:
diff --git a/README.md b/README.md
index fd7d905..394a2af 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,25 @@ Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_do
 and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
 be found at <https://hexdocs.pm/candlex>.
 
+## Usage
+
+#### `NATIVE_BUILD`
+
+Defaults to `false`. If `true` the native binary is built locally, which may be useful
+if no precompiled binary is available for your target environment. Once set, you
+must run `mix deps.clean candlex --build` explicitly to force to recompile.
+Building has a number of dependencies, see *Building from source* below.
+
+## Building from source
+
+To build the native binary locally you need to set `NATIVE_BUILD=true`.
+Keep in mind that the compilation usually takes time.
+
+You will need the following installed in your system for the compilation:
+
+  * [Git](https://git-scm.com) for fetching candle-core source
+  * [Rust](https://www.rust-lang.org) with cargo to compile rustler NIFs
+
 ## Releasing
 
 To publish a new version of this package:
diff --git a/lib/candlex/native.ex b/lib/candlex/native.ex
index 268e96f..bdceb36 100644
--- a/lib/candlex/native.ex
+++ b/lib/candlex/native.ex
@@ -10,7 +10,7 @@ defmodule Candlex.Native do
     otp_app: :candlex,
     features: Application.compile_env(:candlex, :crate_features, []),
     base_url: "#{source_url}/releases/download/v#{version}",
-    force_build: System.get_env("CANDLE_BUILD") in ["1", "true"],
+    force_build: System.get_env("NATIVE_BUILD") in ["1", "true"],
     mode: mode,
     version: version,
     nif_versions: ["2.16"],