Add dockerfile for cross.

This uses the installs Docker from the official sources using the latest Ubuntu image stable, and installs the latest stable Rust version internally. Cross is installed from the latest git (locked), which when tagged will work well with our releases. It exports the environment variable `CROSS_CONTAINER_IN_CONTAINER` so everything should work as expected.

Replaces #667.

.github/workflows/ci.yml

@@ -207,6 +207,7 @@ jobs:
             - { target: thumbv7em-none-eabi,              os: ubuntu-latest,                    std: 1 }
             - { target: thumbv7em-none-eabihf,            os: ubuntu-latest,                    std: 1 }
             - { target: thumbv7m-none-eabi,               os: ubuntu-latest,                    std: 1 }
+            - { target: cross,                            os: ubuntu-latest }
 
   build:
     name: target (${{ matrix.pretty }},${{ matrix.os }})
@@ -283,7 +284,7 @@ jobs:
           IMAGE: ${{ steps.build-docker-image.outputs.image }}
         shell: bash
       - name: Test Image
-        if: steps.prepare-meta.outputs.has-image
+        if: steps.prepare-meta.outputs.has-image && steps.prepare-meta.outputs.test-variant == 'default'
         run: ./ci/test.sh
         env:
           TARGET: ${{ matrix.target }}
@@ -300,6 +301,13 @@ jobs:
           target: ${{ matrix.target }}
           image: ${{ steps.build-docker-image.outputs.image }}
 
+      - name: Test Cross Image
+        if: steps.prepare-meta.outputs.has-image && steps.prepare-meta.outputs.test-variant == 'cross'
+        run: ./ci/test-cross-image.sh
+        env:
+          TARGET: 'aarch64-unknown-linux-gnu'
+        shell: bash
+
       - name: Login to GitHub Container Registry
         if: steps.prepare-meta.outputs.has-image
         uses: docker/login-action@v1

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - #890 - support rootless docker via the `CROSS_ROOTLESS_CONTAINER_ENGINE` environment variable.
+- #878 - added an image `ghcr.io/cross-rs/cross` containing cross.
 
 ### Changed
 

ci/test-cross-image.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC2086
+
+set -x
+set -eo pipefail
+
+if [[ -z "${TARGET}" ]]; then
+    export TARGET="aarch64-unknown-linux-gnu"
+fi
+if [[ -z "${CROSS_TARGET_CROSS_IMAGE}" ]]; then
+    CROSS_TARGET_CROSS_IMAGE="ghcr.io/cross-rs/cross:main"
+fi
+
+main() {
+    docker run --rm -e TARGET \
+        -v /var/run/docker.sock:/var/run/docker.sock \
+        "${CROSS_TARGET_CROSS_IMAGE}" sh -c '
+#!/usr/bin/env sh
+td="$(mktemp -d)"
+git clone --depth 1 https://github.com/cross-rs/rust-cpp-hello-word "${td}"
+cd "${td}"
+cross run --target "${TARGET}"
+'
+}
+
+main "${@}"

docker/Dockerfile.cross

@@ -0,0 +1,22 @@
+FROM ubuntu:20.04 as rust
+ARG DEBIAN_FRONTEND=noninteractive
+COPY docker/lib.sh docker/cross.sh /
+COPY ./ /project
+RUN /cross.sh /project
+
+# we build our images in 2 steps, to ensure we have a compact
+# image, since we want to add our current subdirectory
+FROM ubuntu:20.04
+COPY --from=rust /root/.cargo /root/.cargo
+COPY --from=rust /root/.rustup /root/.rustup
+
+# need some basic devtools, and requirements for docker
+RUN apt-get update && apt-get install --assume-yes --no-install-recommends \
+    ca-certificates \
+    curl \
+    git
+
+RUN curl -fsSL https://get.docker.com | sh
+
+ENV CROSS_CONTAINER_IN_CONTAINER=1 \
+    PATH=/root/.cargo/bin:$PATH

docker/cross.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC1090,SC1091
+
+set -x
+set -euo pipefail
+
+. lib.sh
+
+main() {
+    local project_dir="${1}"
+
+    install_packages ca-certificates curl gcc libc6-dev
+
+    cd "${project_dir}"
+    curl --proto "=https" --tlsv1.2 --retry 3 -sSfL https://sh.rustup.rs | sh -s -- -y
+    source "${HOME}"/.cargo/env
+    cargo install --path . --locked
+
+    purge_packages
+
+    rm -rf "${0}"
+}
+
+main "${@}"

xtask/src/build_docker_image.rs

@@ -144,7 +144,8 @@ pub fn build_docker_image(
         }
     }
     let gha = std::env::var("GITHUB_ACTIONS").is_ok();
-    let docker_root = metadata.workspace_root.join("docker");
+    let root = metadata.workspace_root;
+    let docker_root = root.join("docker");
     let cross_toolchains_root = docker_root.join("cross-toolchains").join("docker");
     let targets = targets
         .into_iter()
@@ -237,7 +238,11 @@ pub fn build_docker_image(
             docker_build.args(&["--build-arg", arg]);
         }
 
-        docker_build.arg(".");
+        if target.needs_workspace_root_context() {
+            docker_build.arg(&root);
+        } else {
+            docker_build.arg(".");
+        }
 
         if !dry_run && (force || !push || gha) {
             let result = docker_build.run(msg_info, false);

xtask/src/ci.rs

@@ -69,6 +69,11 @@ pub fn ci(args: CiJob, metadata: CargoMetadata) -> cross::Result<()> {
             if target.has_ci_image() {
                 gha_output("has-image", "true")
             }
+            if target.is_default_test_image() {
+                gha_output("test-variant", "default")
+            } else {
+                gha_output("test-variant", &target.triplet)
+            }
         }
         CiJob::Check { ref_type, ref_name } => {
             let version = semver::Version::parse(&cross_meta.version)?;

xtask/src/util.rs

@@ -129,6 +129,16 @@ impl ImageTarget {
             .iter()
             .any(|m| m.builds_image() && m.target == self.triplet && m.sub == self.sub)
     }
+
+    /// Determine if this target uses the default test script
+    pub fn is_default_test_image(&self) -> bool {
+        self.triplet != "cross"
+    }
+
+    /// Determine if this target needs to interact with the project root.
+    pub fn needs_workspace_root_context(&self) -> bool {
+        self.triplet == "cross"
+    }
 }
 
 impl std::str::FromStr for ImageTarget {