build: set build_version dynamically (#6013)

Set BUILD_VERSION to the content of the version descriptor (version.txt)
if it changed in the last commit, assuming that the last commit was a
release preparation commit that updated the version descriptor.

Close #4928

.github/workflows/cd.yml

@@ -48,6 +48,13 @@ jobs:
             exit 1
           fi
 
+          . scripts/build-metadata.sh
+
+          if [ -z "${BUILD_DATE}" ]; then
+            echo "[ERROR] BUILD_DATE is empty"
+            exit 1
+          fi
+
           if [ -z "${BUILD_REVISION}" ]; then
             echo "[ERROR] BUILD_REVISION is empty"
             exit 1
@@ -58,8 +65,12 @@ jobs:
             exit 1
           fi
 
+          echo "Build date (GH Actions workflow): ${BUILD_DATE}"
+          echo "Build revision (GH Actions workflow): ${BUILD_REVISION}"
+          echo "Build version (GH Actions workflow): ${BUILD_VERSION}"
+
           {
-            echo "BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ')"
+            echo "BUILD_DATE=${BUILD_DATE}"
             echo "BUILD_REVISION=${BUILD_REVISION}"
             echo "BUILD_VERSION=${BUILD_VERSION}"
           } >> "${GITHUB_ENV}"

.github/workflows/ci.yml

@@ -25,6 +25,9 @@ jobs:
       CONTAINER_IMAGE_BUILD_REVISION: ${{ steps.set-container-image-build-metadata.outputs.CONTAINER_IMAGE_BUILD_REVISION }}
       CONTAINER_IMAGE_BUILD_VERSION: ${{ steps.set-container-image-build-metadata.outputs.CONTAINER_IMAGE_BUILD_VERSION }}
     steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+
       - name: Set build metadata
         id: set-container-image-build-metadata
         run: |
@@ -39,6 +42,13 @@ jobs:
             exit 1
           fi
 
+          . scripts/build-metadata.sh
+
+          if [ -z "${BUILD_DATE}" ]; then
+            echo "[ERROR] BUILD_DATE is empty"
+            exit 1
+          fi
+
           if [ -z "${BUILD_REVISION}" ]; then
             echo "[ERROR] BUILD_REVISION is empty"
             exit 1
@@ -49,11 +59,9 @@ jobs:
             exit 1
           fi
 
-          BUILD_DATE=$(date -u +'%Y-%m-%dT%H:%M:%SZ')
+          echo "Build date (GH Actions workflow): ${BUILD_DATE}"
-
+          echo "Build revision (GH Actions workflow): ${BUILD_REVISION}"
-          echo "Build date: ${BUILD_DATE}"
+          echo "Build version (GH Actions workflow): ${BUILD_VERSION}"
-          echo "Build revision: ${BUILD_REVISION}"
-          echo "Build version: ${BUILD_VERSION}"
 
           {
             echo "BUILD_DATE=${BUILD_DATE}"

Makefile

@@ -82,6 +82,9 @@ info: ## Gather information about the runtime environment
 	echo "whoami: $$(whoami)"; \
 	echo "pwd: $$(pwd)"; \
 	echo "IMAGE:" $(IMAGE); \
+	echo "Build date: ${BUILD_DATE}"; \
+	echo "Build revision: ${BUILD_REVISION}"; \
+	echo "Build version: ${BUILD_VERSION}"; \
 	echo "SUPER_LINTER_TEST_CONTAINER_URL:" $(SUPER_LINTER_TEST_CONTAINER_URL); \
 	echo "ls -ahl: $$(ls -ahl)"; \
 	docker images; \

docs/run-linter-locally.md

@@ -100,11 +100,12 @@ directory, do the following:
 1. Run the build process:
 
     ```bash
-    make
+    . ./scripts/build-metadata.sh && make
     ```
 
-To avoid invalidating the build cache, and reuse it, you can set build metadata
+To avoid invalidating the build cache because of changing values of build
-to arbitrary values before running `make`:
+arguments, you can set build arguments to arbitrary values before running
+`make`, instead of sourcing `scripts/build-metadata.sh`:
 
 ```bash
 BUILD_DATE=2023-12-12T09:32:05Z \

scripts/build-metadata.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+GetBuildDate() {
+  date -u +'%Y-%m-%dT%H:%M:%SZ'
+}
+
+GetBuildRevision() {
+  git rev-parse HEAD
+}
+
+GetBuildVersion() {
+  local VERSION_FILE_PATH="version.txt"
+  local BUILD_REVISION="${1}"
+  # Get the version from the version descriptor if changed in the last commit.
+  # This assumes that the last commit was a "release preparation" commit that
+  # updated the version descriptor
+  if git diff-tree --no-commit-id --name-only -r "${BUILD_REVISION}" | grep -q "${VERSION_FILE_PATH}"; then
+    cat "${VERSION_FILE_PATH}"
+  else
+    GetBuildRevision
+  fi
+}
+
+BUILD_DATE="${BUILD_DATE:-"$(GetBuildDate)"}"
+export BUILD_DATE
+BUILD_REVISION="${BUILD_REVISION:-"$(GetBuildRevision)"}"
+export BUILD_REVISION
+BUILD_VERSION="${BUILD_VERSION:-"$(GetBuildVersion "${BUILD_REVISION}")"}"
+export BUILD_VERSION
+
+echo "Build date: ${BUILD_DATE}"
+echo "Build revision: ${BUILD_REVISION}"
+echo "Build version: ${BUILD_VERSION}"