Add minimal examples of toolchains in WORKSPACEs

.github/workflows/workflow.yaml

@@ -6,11 +6,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-10.15]
+        os: [ubuntu-latest, macos-11]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
-      - uses: cachix/install-nix-action@v14.1
+      - uses: actions/checkout@v2.4.0
+      - uses: cachix/install-nix-action@v16
         with:
           nix_path: nixpkgs=./nixpkgs.nix
       - name: Configure
@@ -27,3 +27,31 @@ jobs:
             set -euo pipefail
             bazel test //...
           '
+  test-examples:
+    name: Build & Test - Examples
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-11]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2.4.0
+      - uses: cachix/install-nix-action@v16
+        with:
+          nix_path: nixpkgs=./nixpkgs.nix
+      - name: Configure
+        env:
+          BUILDBUDDY_API_KEY: ${{ secrets.BUILDBUDDY_API_KEY }}
+        run: |
+          cat >.bazelrc.local <<EOF
+          common --config=ci
+          build --remote_header=x-buildbuddy-api-key="$BUILDBUDDY_API_KEY"
+          EOF
+      - name: Build & test
+        run: |
+          for dir in $PWD/examples/toolchains/*; do
+              cd "$dir"
+              echo
+              echo Running $(head -n1 README.md)
+              nix-shell --command 'bazel run --config=nix :hello'
+          done

examples/.gitignore

@@ -0,0 +1 @@
+bazel-*

examples/toolchains/cc/.bazelrc

@@ -0,0 +1 @@
+build:nix --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host

examples/toolchains/cc/BUILD

@@ -0,0 +1,6 @@
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "hello",
+    srcs = [ "hello.cc" ]
+)

examples/toolchains/cc/README.md

@@ -0,0 +1,17 @@
+C++ Toolchain Example
+=====================
+
+This is an example C++ project that uses `rules_cc`. It should build and run both with or without Nix installed.
+
+# Usage
+
+To run the example with Nix, issue the following command:
+```
+nix-shell --command 'bazel run --config=nix :hello'
+```
+
+To run the example without Nix, make sure you have Bazel installed, and issue the following command:
+```
+bazel run :hello
+```
+This non-Nix example will look for the C++ toolchain on the PATH.

examples/toolchains/cc/WORKSPACE

@@ -0,0 +1,38 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+http_archive(
+    name = "rules_cc",
+    sha256 = "4dccbfd22c0def164c8f47458bd50e0c7148f3d92002cdb459c2a96a68498241",
+    urls = [
+        "https://github.com/bazelbuild/rules_cc/releases/download/0.0.1/rules_cc-0.0.1.tar.gz",
+    ]
+)
+
+local_repository(
+    name = "io_tweag_rules_nixpkgs",
+    path = "../../../"
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:repositories.bzl", "rules_nixpkgs_dependencies")
+rules_nixpkgs_dependencies()
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl",
+     "nixpkgs_git_repository",
+     "nixpkgs_cc_configure"
+)
+nixpkgs_git_repository(
+    name = "nixpkgs",
+    revision = "21.11",
+    sha256 = "c77bb41cf5dd82f4718fa789d49363f512bb6fa6bc25f8d60902fe2d698ed7cc",
+)
+
+nixpkgs_cc_configure(
+        repository = "@nixpkgs",
+        fail_not_supported = False,
+)
+
+load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies", "rules_cc_toolchains")
+
+rules_cc_dependencies()
+
+rules_cc_toolchains()
+

examples/toolchains/cc/hello.cc

@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main()
+{
+	std::cout << "Hello world!\n";
+}

examples/toolchains/cc/shell.nix

@@ -0,0 +1,6 @@
+{ pkgs ? import (builtins.fetchTarball {
+  url = "https://github.com/NixOS/nixpkgs/archive/21.11.tar.gz";
+  sha256 = "162dywda2dvfj1248afxc45kcrg83appjd0nmdb541hl7rnncf02";
+}) { } }:
+
+pkgs.mkShell { nativeBuildInputs = [ pkgs.bazel_4 ]; }

examples/toolchains/go/.bazelrc

@@ -0,0 +1 @@
+build:nix --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host

examples/toolchains/go/BUILD

@@ -0,0 +1,6 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary")
+
+go_binary(
+    name = "hello",
+    srcs = [ "hello.go" ]
+)

examples/toolchains/go/README.md

@@ -0,0 +1,17 @@
+Go Toolchain Example
+====================
+
+This is an example Go project that uses `rules_go`. It should build and run both with or without Nix installed.
+
+# Usage
+
+To run the example with Nix, issue the following command:
+```
+nix-shell --command 'bazel run --config=nix :hello'
+```
+
+To run the example without Nix, make sure you have Bazel installed, and issue the following command:
+```
+bazel run :hello
+```
+This non-Nix example will download a binary distribution of Go's toolchain from the Internet.

examples/toolchains/go/WORKSPACE

@@ -0,0 +1,38 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+http_archive(
+    name = "io_bazel_rules_go",
+    sha256 = "2b1641428dff9018f9e85c0384f03ec6c10660d935b750e3fa1492a281a53b0f",
+    urls = [
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.29.0/rules_go-v0.29.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.29.0/rules_go-v0.29.0.zip",
+    ],
+)
+load("@io_bazel_rules_go//go:deps.bzl", "go_rules_dependencies")
+
+go_rules_dependencies()
+
+local_repository(
+    name = "io_tweag_rules_nixpkgs",
+    path = "../../../"
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:repositories.bzl", "rules_nixpkgs_dependencies")
+rules_nixpkgs_dependencies()
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_git_repository")
+nixpkgs_git_repository(
+    name = "nixpkgs",
+    revision = "21.11",
+    sha256 = "c77bb41cf5dd82f4718fa789d49363f512bb6fa6bc25f8d60902fe2d698ed7cc",
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:toolchains/go.bzl", "nixpkgs_go_configure")
+nixpkgs_go_configure(
+    sdk_name = "nix_go",
+    repository = "@nixpkgs",
+    fail_not_supported = False,
+)
+
+load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
+go_rules_dependencies()
+go_register_toolchains(version = "1.17.1")

examples/toolchains/go/hello.go

@@ -0,0 +1,7 @@
+package main
+
+import "fmt"
+
+func main() {
+    fmt.Println("Hello world!")
+}

examples/toolchains/go/shell.nix

@@ -0,0 +1,6 @@
+{ pkgs ? import (builtins.fetchTarball {
+  url = "https://github.com/NixOS/nixpkgs/archive/21.11.tar.gz";
+  sha256 = "162dywda2dvfj1248afxc45kcrg83appjd0nmdb541hl7rnncf02";
+}) { } }:
+
+pkgs.mkShell { nativeBuildInputs = [ pkgs.bazel_4 ]; }

examples/toolchains/python/.bazelrc

@@ -0,0 +1 @@
+build:nix --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host

examples/toolchains/python/BUILD

@@ -0,0 +1,5 @@
+py_binary(
+    name = "hello",
+    srcs = [ "hello.py"],
+    main = "hello.py",
+)

examples/toolchains/python/README.md

@@ -0,0 +1,13 @@
+Python Toolchain Example
+========================
+
+This is an example Python project with modules that uses `rules_python`. Providing Python modules without Nix is currently not supported.
+
+# Usage
+
+To run the example with Nix, issue the following command:
+```
+nix-shell --command 'bazel run --config=nix :hello'
+```
+
+To specify Python version or modules, change the `python3_attribute_path` parameter in the `nixpkgs_python_configure` call in the `WORKSPACE` file.

examples/toolchains/python/WORKSPACE

@@ -0,0 +1,22 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+local_repository(
+    name = "io_tweag_rules_nixpkgs",
+    path = "../../.."
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:repositories.bzl", "rules_nixpkgs_dependencies")
+rules_nixpkgs_dependencies()
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_git_repository")
+nixpkgs_git_repository(
+    name = "nixpkgs",
+    revision = "21.11",
+    sha256 = "c77bb41cf5dd82f4718fa789d49363f512bb6fa6bc25f8d60902fe2d698ed7cc",
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_python_configure")
+nixpkgs_python_configure(
+    repository = "@nixpkgs",
+    python3_attribute_path = "python39.withPackages(ps: with ps; [ numpy opencv4 ])"
+)

examples/toolchains/python/hello.py

@@ -0,0 +1,4 @@
+import cv2
+import numpy
+
+print("Hello world!")

examples/toolchains/python/shell.nix

@@ -0,0 +1,6 @@
+{ pkgs ? import (builtins.fetchTarball {
+  url = "https://github.com/NixOS/nixpkgs/archive/21.11.tar.gz";
+  sha256 = "162dywda2dvfj1248afxc45kcrg83appjd0nmdb541hl7rnncf02";
+}) { } }:
+
+pkgs.mkShell { nativeBuildInputs = [ pkgs.bazel_4 ]; }