chore: split pre-commit tool image from devcontainer

.devcontainer/devcontainer-bake.hcl

@@ -2,6 +2,8 @@ variable "devcontainer_layers" {
   default = [
     "docker-client",
     "useradd",
+    "pre-commit-base",
+    "pre-commit-tool-image",
     "pre-commit"
   ]
 }

.devcontainer/initialize

@@ -16,4 +16,6 @@ devcontainer_definition_files_arr=(
 DEVCONTAINER_DEFINITION_FILES="${devcontainer_definition_files_arr[*]}"
 export DEVCONTAINER_DEFINITION_FILES
 export DEVCONTAINER_BUILD_ADDITIONAL_ARGS="$*"
-curl https://raw.githubusercontent.com/rcwbr/devcontainer-cache-build/0.4.0/devcontainer-cache-build-initialize | bash
+# curl https://raw.githubusercontent.com/rcwbr/devcontainer-cache-build/0.4.0/devcontainer-cache-build-initialize | bash
+# DEVCONTAINER_CACHE_BUILD_IMAGE=ghcr.io/rcwbr/devcontainer-cache-build:19-fix-handling-of-empty-target-outputs-b4767c26dfddada604ed9539bddc5d4c47042ad4
+curl https://raw.githubusercontent.com/rcwbr/devcontainer-cache-build/test/19/devcontainer-cache-build-initialize | bash # TODO revert

devcontainer-bake.hcl

@@ -52,6 +52,5 @@ target "layer" {
 }
 
 group "default" {
-  // Target the last layer as default
-  targets = [devcontainer_layers[length(devcontainer_layers) - 1]]
+  targets = devcontainer_layers
 }

pre-commit/Dockerfile

@@ -1,11 +1,7 @@
-# hadolint ignore=DL3006
-FROM common_context AS common_context
-
 # Set base_context in the downstream Bake file
 # hadolint ignore=DL3006
 FROM base_context
-ARG USER=root
-# Assume root role for installs
+# Act as root in this image
 USER root
 # Install git (if not already available) to spoof pre-commit environment
 SHELL [ "/bin/bash", "-c" ]
@@ -23,19 +19,13 @@ RUN DEBIAN_FRONTEND=noninteractive \
 
 # Prep folder for pre-commit
 ENV DEVCONTAINER_PRE_COMMIT=/opt/devcontainers/pre-commit
-RUN \
-  mkdir -p "$DEVCONTAINER_PRE_COMMIT" \
-  && chmod a+rx "$DEVCONTAINER_PRE_COMMIT" \
-  && chown -R $USER:$USER "$DEVCONTAINER_PRE_COMMIT"
-# Apply spoof pre-commit executable
-COPY pre-commit/pre-commit /usr/local/bin
-USER ${USER}
 # Create a temp repo and install the hooks from the config
 # Load the config file from the downstream context
 # hadolint ignore=DL3003,SC1091
 RUN \
   --mount=type=bind,from=local_context,source=.pre-commit-config.yaml,target=/tmp/.pre-commit-config.yaml \
-  python -m venv "$DEVCONTAINER_PRE_COMMIT/venv" \
+  mkdir -p "$DEVCONTAINER_PRE_COMMIT" \
+  && python -m venv "$DEVCONTAINER_PRE_COMMIT/venv" \
   && source "$DEVCONTAINER_PRE_COMMIT/venv/bin/activate" \
   && mkdir "$DEVCONTAINER_PRE_COMMIT/tmp_repo" \
   && cd "$DEVCONTAINER_PRE_COMMIT/tmp_repo" \
@@ -45,7 +35,3 @@ RUN \
   && pre-commit install-hooks \
   && cd "$DEVCONTAINER_PRE_COMMIT" \
   && rm -rf "$DEVCONTAINER_PRE_COMMIT/tmp_repo"
-
-COPY --from=common_context on_create_command /opt/devcontainers/on_create_command
-# Include pre-commit initialization in config for devcontainers onCreateCommand
-COPY pre-commit/on_create_command /opt/devcontainers/on_create_command

pre-commit/caller.Dockerfile

@@ -0,0 +1,15 @@
+# hadolint ignore=DL3006
+FROM common_context AS common_context
+
+# hadolint ignore=DL3006
+FROM base_context
+ARG USER=root
+USER $USER
+ARG DEVCONTAINER_PRE_COMMIT_IMAGE
+# Burn the pre-commit image ref into the image for use in the caller script
+ENV DEVCONTAINER_PRE_COMMIT_IMAGE=$DEVCONTAINER_PRE_COMMIT_IMAGE
+# Apply pre-commit caller executable
+COPY pre-commit/pre-commit /usr/local/bin
+COPY --from=common_context on_create_command /opt/devcontainers/on_create_command
+# Include pre-commit initialization in config for devcontainers onCreateCommand
+COPY pre-commit/on_create_command /opt/devcontainers/on_create_command

pre-commit/devcontainer-bake.hcl

@@ -1,14 +1,40 @@
 variable "USER" {
   default = "root"
 }
+variable "DEVCONTAINER_REGISTRY" {
+  default = ""
+}
+variable "DEVCONTAINER_IMAGE" {
+  default = ""
+}
+variable "PRE_COMMIT_TOOL_IMAGE" {
+  default = "type=registry,name=${DEVCONTAINER_REGISTRY}:${DEVCONTAINER_IMAGE}-pre-commit"
+}
 
-target "pre-commit" {
+target "pre-commit-base" {
+  dockerfile-inline = "FROM base_context"
+}
+
+target "pre-commit-tool-image" {
   dockerfile = "pre-commit/Dockerfile"
+  contexts = {
+    local_context = BAKE_CMD_CONTEXT
+    base_context  = "target:pre-commit-base"
+  }
+  output = ["${PRE_COMMIT_TOOL_IMAGE}"]
+}
+
+target "pre-commit" {
+  dockerfile = "pre-commit/caller.Dockerfile"
   contexts = {
     local_context  = BAKE_CMD_CONTEXT
     common_context = "common"
+    base_context   = "target:pre-commit-base"
+    // Tool context is unused; referenced only to establish it as a dep
+    tool_context   = "target:pre-commit-tool-image"
   }
   args = {
     USER = "${USER}"
+    DEVCONTAINER_PRE_COMMIT_IMAGE = "${PRE_COMMIT_TOOL_IMAGE}"
   }
 }

pre-commit/pre-commit

@@ -1,3 +1,19 @@
 #!/bin/bash
 
-PATH="$DEVCONTAINER_PRE_COMMIT/venv/bin:$PATH" "$DEVCONTAINER_PRE_COMMIT/venv/bin/pre-commit" "$@"
+set -e
+
+export PRE_COMMIT_ARGS=($@)
+docker run \
+  --rm \
+  -it \
+  --name pre-commit \
+  --user root \
+  --entrypoint bash \
+  -v "$(pwd):$(pwd)" \
+  -w "$(pwd)" \
+  -e DEVCONTAINER_PRE_COMMIT \
+  -e PRE_COMMIT_ARGS \
+  "$DEVCONTAINER_PRE_COMMIT_IMAGE" \
+  -c 'git config --global --add safe.directory "$(pwd)" && PATH="$DEVCONTAINER_PRE_COMMIT/venv/bin:$PATH" "$DEVCONTAINER_PRE_COMMIT/venv/bin/pre-commit" "${PRE_COMMIT_ARGS[@]}"'
+
+sudo chown -R $USER:$USER $(pwd)