Use Javascript action instead of composite action'

.bazelversion

@@ -0,0 +1 @@
+7.4.1

.github/workflows/ci.yaml

@@ -134,6 +134,23 @@ jobs:
             exit 1
           fi
           echo "SUCCESS"
+      - name: Execute with output
+        id: sample
+        uses: ./
+        with:
+          derivation-path: ./tests/integration_tests
+          pure: false
+          run: |-
+            echo "what=thing" >> "$GITHUB_OUTPUT"
+      - name: Confirm that output was propagated
+        shell: bash
+        run: |-
+          actual='${{ steps.sample.outputs.what }}'
+          if [[ "$actual" != 'thing' ]]; then
+            echo >&2 "The output from \`sample\` was wrong. Wanted \`thing\` but got \`${actual}\`"
+            exit 1
+          fi
+
 
   all_ci_tests:
     runs-on: ubuntu-latest

.gitignore

@@ -1,3 +1,4 @@
 bazel-*
 
 .direnv
+node_modules/

BUILD.bazel

@@ -1,3 +1,5 @@
+load("@cgrindel_bazel_starlib//updatesrc:defs.bzl", "updatesrc_diff_and_update")
+
 # exports_files(["flake.lock"])
 
 filegroup(
@@ -8,3 +10,29 @@ filegroup(
     ],
     visibility = ["//:__subpackages__"],
 )
+
+genrule(
+    name = "dist",
+    cmd = """
+    set -euo pipefail
+    # provide a writable home dir
+    export HOME="$$(pwd)/NOHOME"
+    mkdir "$$HOME"
+    # index.js should not be a symlink
+    cat index.js > i.js && mv i.js index.js
+    BUN=$(location @bun//:bin/bun)
+    $$BUN install --no-save
+    $$BUN build --target=node --outfile=$@ $(location index.js)
+    """,
+    srcs = ["package.json", "bun.lockb", "index.js"],
+    tags = ["requires-network"],
+    tools = ["@nodejs//:bin/npm", "@bun//:bin/bun"],
+    outs = ["generated/bundle.mjs"],
+    visibility = ["//:__subpackages__"],
+)
+
+updatesrc_diff_and_update(
+    name = "update",
+    srcs = ["dist/bundle.mjs"],
+    outs = [":dist"],
+)

MODULE.bazel

@@ -13,3 +13,26 @@ bazel_dep(
     version = "0.18.1",
     dev_dependency = True,
 )
+
+nix_repo = use_extension("@rules_nixpkgs_core//extensions:repository.bzl", "nix_repo")
+nix_repo.file(
+    name = "nixpkgs",
+    file = ":nixpkgs.nix",
+    file_deps = [":flake.lock"],
+)
+use_repo(nix_repo, "nixpkgs")
+
+nix_pkg = use_extension("@rules_nixpkgs_core//extensions:package.bzl", "nix_pkg")
+nix_pkg.attr(
+    name = "nodejs",
+    # keep this in sync with action.yaml
+    attr = "nodejs_20",
+    repo = "@nixpkgs",
+)
+use_repo(nix_pkg, "nodejs")
+
+nix_pkg.attr(
+    attr = "bun",
+    repo = "@nixpkgs",
+)
+use_repo(nix_pkg, "bun")

action.yaml

@@ -32,18 +32,10 @@ inputs:
     description: Enable debug output written to stderr.
     default: false
 
+outputs:
+  outputs:
+    description: The outputs of the nix-shell-run
+
 runs:
-  using: composite
-  steps:
-    - shell: bash
-      env:
-        RNS_CWD: ${{ inputs.working-directory }}
-        RNS_OPTS: ${{ inputs.options }}
-        RNS_RUN: ${{ inputs.run }}
-        RNS_PURE: ${{ inputs.pure }}
-        RNS_DERIVATION_PATH: ${{ inputs.derivation-path }}
-        RNS_VERBOSE: ${{ inputs.verbose }}
-        # If the client specifies an empty string for the flags, we need to set the RNS_SHELL_FLAGS 
-        # env variable to the special value false.
-        RNS_SHELL_FLAGS: ${{ inputs.shell-flags == '' && 'false' || inputs.shell-flags }}
-      run: ${GITHUB_ACTION_PATH}/tools/run_nix_shell.sh
+  using: node20                 # keep this in sync with @nodejs in MODULE.bazel
+  main: dist/bundle.mjs