.github: set up elixir ci

Signed-off-by: Nathan Perry <nathan@tailscale.com>
Change-Id: I1d436f03dc140f2d11e1689de2c1b34e6a6a6964

Author: npry

.github/workflows/elixir.yml

@@ -0,0 +1,122 @@
+name: elixir
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - v*
+  pull_request:
+  workflow_dispatch:
+  schedule:
+    # Nightly run; execute daily at 07:37 AM UTC on main (default branch). This is an hour
+    # after the Rust checks.
+    - cron: '37 7 * * *'
+
+permissions:
+  contents: read
+
+env:
+  # cache-busting key -- change it if the build changes in a way that invalidates old
+  # cached state
+  cache_key: init
+
+jobs:
+  build_test:
+    name: compile, test, static checks (elixir ${{ matrix.elixir.label }}, otp ${{ matrix.otp.label }}, rust ${{ matrix.rust_toolchain.label }})
+    runs-on: linux-x86_64-16cpu
+
+    strategy:
+      matrix:
+        elixir:
+          - version: 1.19.5
+            label: latest
+        otp:
+          - version: 28.4.2
+            label: latest
+        rust_toolchain:
+          - version: 1.94.0
+            label: latest
+
+    defaults:
+      run:
+        working-directory: ts_elixir
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Cache mix
+        id: cache-mix
+        uses: actions/cache@v5
+        with:
+          path: |
+            ~/.mix
+            ts_elixir/_build/
+            ts_elixir/deps/
+          key: ${{ runner.os }}-mix-${{ env.cache_key }}-elixir-${{ matrix.elixir.version }}-otp-${{ matrix.otp.version }}-${{ hashFiles('**/mix.lock') }}
+
+      - name: Cache Rust
+        id: cache-rust-elixir
+        uses: actions/cache@v5
+        with:
+          path: |
+            ~/.cargo/bin/
+            ~/.cargo/registry/index/
+            ~/.cargo/registry/cache/
+            ~/.cargo/git/db/
+            ~/.rustup/toolchains
+            target/
+          key: ${{ runner.os }}-elixir-rs-${{ env.cache_key }}-${{ matrix.rust_toolchain.version }}-${{ hashFiles('**/Cargo.lock') }}
+
+      - name: Install elixir
+        id: install-elixir
+        uses: erlef/setup-beam@v1.24.0
+        with:
+          otp-version: ${{ matrix.otp.version }}
+          elixir-version: ${{ matrix.elixir.version }}
+
+      - name: Install Rust toolchain
+        id: install-rust-toolchain
+        if: steps.cache-rust-elixir.outputs.cache-hit != 'true'
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.rust_toolchain.version }}
+
+      - name: Install dependencies
+        run: mix deps.get
+
+      - name: Compile dependencies
+        run: mix deps.compile
+
+      - name: Compile (MIX_ENV=dev)
+        run: mix compile --warnings-as-errors
+
+      - name: Compile (MIX_ENV=prod)
+        run: mix compile --warnings-as-errors
+        env:
+          MIX_ENV: prod
+
+      - name: Format
+        run: mix format --check-formatted
+
+      - name: Test
+        run: mix test
+        env:
+          # TODO(npry): testing tailnet + set TS_RS_TEST_AUTHKEY
+          TS_RS_TEST_NET: 0
+
+      - name: Dialyzer
+        run: mix dialyzer --format github
+
+      - name: Credo
+        run: mix credo list --format oneline
+
+      - name: Docs
+        run: mix docs --warnings-as-errors
+
+      - name: Upload docs
+        uses: actions/upload-artifact@v7
+        with:
+          name: exdoc-${{ github.sha }}
+          path: ts_elixir/doc
+          retention-days: 7

ts_elixir/mix.exs

@@ -56,6 +56,9 @@ defmodule TsElixir.MixProject do
       api_reference: true,
       extras: ["README.md"],
       formatters: ["html"],
+      # The :tailscale* erlang-style modules generate paths like :tailscale.html, which is invalid.
+      # Exclude from ExDoc for now.
+      filter_modules: ~r/Elixir\..*/,
       groups_for_modules: [
         Tcp: [
           Tailscale.Tcp,