build-contexts input

.github/workflows/ci.yml

@@ -388,6 +388,27 @@ jobs:
             docker:10.180.0.1
             foo:10.0.0.1
 
+  build-contexts:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          version: v0.8.0
+      -
+        name: Build
+        uses: ./
+        with:
+          context: ./test
+          file: ./test/buildcontext.Dockerfile
+          build-contexts: |
+            alpine=docker-image://debian:stable-slim
+          tags: name/app:latest
+
   multi:
     runs-on: ubuntu-latest
     strategy:

README.md

@@ -202,10 +202,11 @@ Following inputs can be used as `step.with` keys
 | `add-hosts`         | List/CSV | List of [customs host-to-IP mapping](https://docs.docker.com/engine/reference/commandline/build/#add-entries-to-container-hosts-file---add-host) (e.g., `docker:10.180.0.1`) |
 | `allow`             | List/CSV | List of [extra privileged entitlement](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#allow) (e.g., `network.host,security.insecure`) |
 | `builder`           | String   | Builder instance (see [setup-buildx](https://github.com/docker/setup-buildx-action) action) |
-| `build-args`        | List     | List of build-time variables |
+| `build-args`        | List     | List of [build-time variables](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#build-arg) |
+| `build-contexts`    | List     | List of additional [build contexts](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#build-context) (e.g., `name=path`) |
 | `cache-from`        | List     | List of [external cache sources](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#cache-from) (e.g., `type=local,src=path/to/dir`) |
 | `cache-to`          | List     | List of [cache export destinations](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#cache-to) (e.g., `type=local,dest=path/to/dir`) |
-| `cgroup-parent`¹    | String   | Optional [parent cgroup](https://docs.docker.com/engine/reference/commandline/build/#use-a-custom-parent-cgroup---cgroup-parent) for the container used in the build |
+| `cgroup-parent`     | String   | Optional [parent cgroup](https://docs.docker.com/engine/reference/commandline/build/#use-a-custom-parent-cgroup---cgroup-parent) for the container used in the build |
 | `context`           | String   | Build's context is the set of files located in the specified [`PATH` or `URL`](https://docs.docker.com/engine/reference/commandline/build/) (default [Git context](#git-context)) |
 | `file`              | String   | Path to the Dockerfile. (default `{context}/Dockerfile`) |
 | `labels`            | List     | List of metadata for an image |
@@ -214,27 +215,17 @@ Following inputs can be used as `step.with` keys
 | `no-cache`          | Bool     | Do not use cache when building the image (default `false`) |
 | `outputs`           | List     | List of [output destinations](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#output) (format: `type=local,dest=path`) |
 | `platforms`         | List/CSV | List of [target platforms](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#platform) for build |
-| `pull`              | Bool     | Always attempt to pull a newer version of the image (default `false`) |
+| `pull`              | Bool     | Always attempt to pull all referenced images (default `false`) |
 | `push`              | Bool     | [Push](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#push) is a shorthand for `--output=type=registry` (default `false`) |
-| `secrets`           | List     | List of secrets to expose to the build (e.g., `key=string`, `GIT_AUTH_TOKEN=mytoken`) |
-| `secret-files`      | List     | List of secret files to expose to the build (e.g., `key=filename`, `MY_SECRET=./secret.txt`) |
-| `shm-size`¹         | String   | Size of [`/dev/shm`](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#-size-of-devshm---shm-size) (e.g., `2g`) |
-| `ssh`               | List     | List of SSH agent socket or keys to expose to the build |
+| `secrets`           | List     | List of [secrets](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#secret) to expose to the build (e.g., `key=string`, `GIT_AUTH_TOKEN=mytoken`) |
+| `secret-files`      | List     | List of [secret files](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#secret) to expose to the build (e.g., `key=filename`, `MY_SECRET=./secret.txt`) |
+| `shm-size`          | String   | Size of [`/dev/shm`](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#-size-of-devshm---shm-size) (e.g., `2g`) |
+| `ssh`               | List     | List of [SSH agent socket or keys](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#ssh) to expose to the build |
 | `tags`              | List/CSV | List of tags |
 | `target`            | String   | Sets the target stage to build |
-| `ulimit`¹           | List     | [Ulimit](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#-set-ulimits---ulimit) options (e.g., `nofile=1024:1024`) |
+| `ulimit`            | List     | [Ulimit](https://github.com/docker/buildx/blob/master/docs/reference/buildx_build.md#-set-ulimits---ulimit) options (e.g., `nofile=1024:1024`) |
 | `github-token`      | String   | GitHub Token used to authenticate against a repository for [Git context](#git-context) (default `${{ github.token }}`) |
 
-> ¹ `cgroup-parent`, `shm-size` and `ulimit` are only available using `moby/buildkit:master`
-> as builder image atm:
-> ```yaml
-> - name: Set up Docker Buildx
->   uses: docker/setup-buildx-action@v1
->   with:
->   driver-opts: |
->     image=moby/buildkit:master
-> ```
-
 ### outputs
 
 Following outputs are available

action.yml

@@ -16,6 +16,9 @@ inputs:
   build-args:
     description: "List of build-time variables"
     required: false
+  build-contexts:
+    description: "List of additional build contexts (e.g., name=path)"
+    required: false
   builder:
     description: "Builder instance"
     required: false
@@ -55,7 +58,7 @@ inputs:
     description: "List of target platforms for build"
     required: false
   pull:
-    description: "Always attempt to pull a newer version of the image"
+    description: "Always attempt to pull all referenced images"
     required: false
     default: 'false'
   push:

src/context.ts

@@ -17,6 +17,7 @@ export interface Inputs {
   addHosts: string[];
   allow: string[];
   buildArgs: string[];
+  buildContexts: string[];
   builder: string;
   cacheFrom: string[];
   cacheTo: string[];
@@ -71,6 +72,7 @@ export async function getInputs(defaultContext: string): Promise<Inputs> {
     addHosts: await getInputList('add-hosts'),
     allow: await getInputList('allow'),
     buildArgs: await getInputList('build-args', true),
+    buildContexts: await getInputList('build-contexts', true),
     builder: core.getInput('builder'),
     cacheFrom: await getInputList('cache-from', true),
     cacheTo: await getInputList('cache-to', true),
@@ -115,6 +117,11 @@ async function getBuildArgs(inputs: Inputs, defaultContext: string, buildxVersio
   await asyncForEach(inputs.buildArgs, async buildArg => {
     args.push('--build-arg', buildArg);
   });
+  if (buildx.satisfies(buildxVersion, '>=0.8.0')) {
+    await asyncForEach(inputs.buildContexts, async buildContext => {
+      args.push('--build-context', buildContext);
+    });
+  }
   await asyncForEach(inputs.cacheFrom, async cacheFrom => {
     args.push('--cache-from', cacheFrom);
   });

test/buildcontext.Dockerfile

@@ -0,0 +1,3 @@
+# syntax=docker/dockerfile-upstream:master
+FROM alpine
+RUN cat /etc/*release