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 cross-rs#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.default-test
         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.default-test
+        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

@@ -7,6 +7,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased] - ReleaseDate
 
+### Added
+
+- #878 - added a dockerfile containing cross.
+
 ### Changed
 
 - #869 - ensure cargo configuration environment variable flags are passed to the docker container.

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 +1,21 @@
+FROM ubuntu:20.04 as rust
+ARG DEBIAN_FRONTEND=noninteractive
+COPY lib.sh cross.sh /
+RUN /cross.sh
+
+# 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 +1,23 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC1090,SC1091
+
+set -x
+set -euo pipefail
+
+. lib.sh
+
+main() {
+    install_packages ca-certificates curl gcc libc6-dev
+
+    # since we can't share outside the current docker context,
+    # we need to install from git, rather than from path
+    curl --proto "=https" --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
+    source "$HOME"/.cargo/env
+    cargo install cross --git https://github.com/cross-rs/cross --locked
+
+    purge_packages
+
+    rm -rf "${0}"
+}
+
+main "${@}"

xtask/src/ci.rs

@@ -69,6 +69,9 @@ 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("default-test", "true")
+            }
         }
         CiJob::Check { ref_type, ref_name } => {
             let version = semver::Version::parse(&cross_meta.version)?;

xtask/src/util.rs

@@ -129,6 +129,11 @@ 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"
+    }
 }
 
 impl std::str::FromStr for ImageTarget {