refactor: 使用 buildx 跨平台构建并发布镜像

DEPLOY.md

@@ -15,11 +15,21 @@ Use `publish.sh` — it reads the current version from this file, bumps the mino
 ./publish.sh 2.0    # publish an explicit version instead
 ```
 
+## Cross-building
+
+The dev machine is an Apple Silicon Mac (arm64) while the target server is
+Ubuntu 22.04 x86_64, so images are cross-built with `docker buildx` for
+`linux/amd64` and pushed straight to the registry (`--push`). Requires a
+buildx builder with amd64 support (OrbStack / Docker Desktop provide one by
+default, e.g. via QEMU emulation).
+
 ## Build & push (manual)
 
 ```sh
-docker build --build-arg VERSION=1.10 -t 192.168.2.212:3000/tigeren/metube:1.10 .
-docker push 192.168.2.212:3000/tigeren/metube:1.10
+docker buildx build --platform linux/amd64 \
+  --build-arg VERSION=1.10 \
+  -t 192.168.2.212:3000/tigeren/metube:1.10 \
+  --push .
 ```
 
 ## Run

Dockerfile

@@ -1,4 +1,6 @@
-FROM node:lts-alpine AS builder
+# Pin the UI builder to the build host platform: its output is just static
+# files, so there is no need to run node under QEMU when cross-building.
+FROM --platform=$BUILDPLATFORM node:lts-alpine AS builder
 
 WORKDIR /metube
 COPY ui ./

publish.sh

@@ -5,7 +5,8 @@
 #   - The version recorded in DEPLOY.md (checked into git) is the current
 #     online version.
 #   - Publishing bumps the minor number of that version, updates DEPLOY.md,
-#     builds the image with --build-arg VERSION=<new> and pushes it.
+#     cross-builds the image for the target platform (buildx) with
+#     --build-arg VERSION=<new> and pushes it to the registry.
 #
 # Usage:
 #   ./publish.sh            # bump minor of the current version (e.g. 1.10 -> 1.11)
@@ -16,8 +17,13 @@ cd "$(dirname "$0")"
 
 DEPLOY_FILE="DEPLOY.md"
 
-# Current image reference (with tag), taken from the build command in DEPLOY.md
-CURRENT_REF=$(grep -oP '(?<=-t )\S+:[0-9]+\.[0-9]+' "$DEPLOY_FILE" | head -1)
+# Deployment target platform (Ubuntu 22.04 x86_64). The local dev machine is
+# Apple Silicon (arm64), so builds go through `docker buildx`.
+PLATFORM="linux/amd64"
+
+# Current image reference (with tag), taken from the build command in DEPLOY.md.
+# Written with POSIX sed so it works with macOS's BSD userland (no GNU grep -P).
+CURRENT_REF=$(sed -n 's/.*-t \([^ ]*:[0-9][0-9]*\.[0-9][0-9]*\).*/\1/p' "$DEPLOY_FILE" | head -1)
 if [[ -z "$CURRENT_REF" ]]; then
   echo "Error: could not find an image reference like '-t <registry>/<image>:<major>.<minor>' in $DEPLOY_FILE" >&2
   exit 1
@@ -46,11 +52,24 @@ fi
 
 echo "Publishing $IMAGE:$NEW_VERSION (current: $CURRENT_VERSION)"
 
-# Record the new version as the current online version
-sed -i "s/VERSION=${CURRENT_VERSION}\b/VERSION=${NEW_VERSION}/g; s/:${CURRENT_VERSION}\b/:${NEW_VERSION}/g" "$DEPLOY_FILE"
+# Record the new version as the current online version. BSD sed has no `\b`,
+# so require a non-digit (or end of line) after the version to avoid matching
+# e.g. 1.1 inside 1.10.
+sed -i '' \
+  -e "s/VERSION=${CURRENT_VERSION}\([^0-9.]\)/VERSION=${NEW_VERSION}\1/g" \
+  -e "s/VERSION=${CURRENT_VERSION}\$/VERSION=${NEW_VERSION}/g" \
+  -e "s/:${CURRENT_VERSION}\([^0-9.]\)/:${NEW_VERSION}\1/g" \
+  -e "s/:${CURRENT_VERSION}\$/:${NEW_VERSION}/g" \
+  "$DEPLOY_FILE"
 
-docker build --build-arg "VERSION=$NEW_VERSION" -t "$IMAGE:$NEW_VERSION" .
-docker push "$IMAGE:$NEW_VERSION"
+# Cross-build from the local machine (e.g. Apple Silicon) for the deployment
+# target platform and push directly to the registry in one buildx invocation.
+docker buildx build \
+  --platform "$PLATFORM" \
+  --build-arg "VERSION=$NEW_VERSION" \
+  -t "$IMAGE:$NEW_VERSION" \
+  --push \
+  .
 
 echo
 echo "Published $IMAGE:$NEW_VERSION"