feat: enable hermetic library generation

.github/scripts/hermetic_library_generation.sh

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+#!/bin/bash
+set -e
+# This script should be run at the root of the repository.
+# This script is used to, when a pull request changes the generation
+# configuration (generation_config.yaml by default):
+# 1. Find whether the last commit in this pull request contains changes to
+# the generation configuration and exit early if it doesn't have such a change
+# since the generation result would be the same.
+# 2. Compare generation configurations in the current branch (with which the
+# pull request associated) and target branch (into which the pull request is
+# merged);
+# 3. Generate changed libraries using library_generation image;
+# 4. Commit the changes to the pull request, if any.
+# 5. Edit the PR body with generated pull request description, if applicable.
+
+# The following commands need to be installed before running the script:
+# 1. git
+# 2. gh
+# 3. docker
+
+# The parameters of this script is:
+# 1. target_branch, the branch into which the pull request is merged.
+# 2. current_branch, the branch with which the pull request is associated.
+# 3. [optional] generation_config, the path to the generation configuration,
+# the default value is generation_config.yaml in the repository root.
+while [[ $# -gt 0 ]]; do
+key="$1"
+case "${key}" in
+  --target_branch)
+    target_branch="$2"
+    shift
+    ;;
+  --current_branch)
+    current_branch="$2"
+    shift
+    ;;
+  --generation_config)
+    generation_config="$2"
+    shift
+    ;;
+  *)
+    echo "Invalid option: [$1]"
+    exit 1
+    ;;
+esac
+shift
+done
+
+if [ -z "${target_branch}" ]; then
+  echo "missing required argument --target_branch"
+  exit 1
+fi
+
+if [ -z "${current_branch}" ]; then
+  echo "missing required argument --current_branch"
+  exit 1
+fi
+
+if [ -z "${generation_config}" ]; then
+  generation_config=generation_config.yaml
+  echo "Using default generation config: ${generation_config}"
+fi
+
+workspace_name="/workspace"
+baseline_generation_config="baseline_generation_config.yaml"
+message="chore: generate libraries at $(date)"
+
+git checkout "${target_branch}"
+git checkout "${current_branch}"
+# if the last commit doesn't contain changes to generation configuration,
+# do not generate again as the result will be the same.
+change_of_last_commit="$(git diff-tree --no-commit-id --name-only HEAD~1..HEAD -r)"
+if [[ ! ("${change_of_last_commit}" == *"${generation_config}"*) ]]; then
+    echo "The last commit doesn't contain any changes to the generation_config.yaml, skipping the whole generation process." || true
+    exit 0
+fi
+# copy generation configuration from target branch to current branch.
+git show "${target_branch}":"${generation_config}" > "${baseline_generation_config}"
+config_diff=$(diff "${generation_config}" "${baseline_generation_config}" || true)
+
+# parse image tag from the generation configuration.
+image_tag=$(grep "gapic_generator_version" "${generation_config}" | cut -d ':' -f 2 | xargs)
+
+# run hermetic code generation docker image.
+docker run \
+  --rm \
+  -u "$(id -u):$(id -g)" \
+  -v "$(pwd):${workspace_name}" \
+  gcr.io/cloud-devrel-public-resources/java-library-generation:"${image_tag}" \
+  --baseline-generation-config-path="${workspace_name}/${baseline_generation_config}" \
+  --current-generation-config-path="${workspace_name}/${generation_config}"
+
+
+# commit the change to the pull request.
+if [[ $(basename $(pwd)) == "google-cloud-java" ]]; then
+  git add java-* pom.xml gapic-libraries-bom/pom.xml versions.txt
+else
+  # The image leaves intermediate folders and files it works with. Here we remove them
+  rm -rdf output googleapis "${baseline_generation_config}"
+  git add --all -- ':!pr_description.txt'
+fi
+changed_files=$(git diff --cached --name-only)
+if [[ "${changed_files}" == "" ]]; then
+    echo "There is no generated code change with the generation config change ${config_diff}."
+    echo "Skip committing to the pull request."
+    exit 0
+fi
+
+echo "Configuration diff:"
+echo "${config_diff}"
+git commit -m "${message}"
+git push
+# set pr body if pr_description.txt is generated.
+if [[ -f "pr_description.txt" ]]; then
+  pr_num=$(gh pr list -s open -H "${current_branch}" -q . --json number | jq ".[] | .number")
+  gh pr edit "${pr_num}" --body "$(cat pr_description.txt)"
+fi

.github/scripts/update_generation_config.sh

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+#!/bin/bash
+set -e
+# This script should be run at the root of the repository.
+# This script is used to update googleapis_commitish, gapic_generator_version,
+# and libraries_bom_version in generation configuration at the time of running
+# and create a pull request.
+
+# The following commands need to be installed before running the script:
+# 1. git
+# 2. gh
+# 3. jq
+
+# Utility functions
+# Get the latest released version of a Maven artifact.
+function get_latest_released_version() {
+    local group_id=$1
+    local artifact_id=$2
+    latest=$(curl -s "https://search.maven.org/solrsearch/select?q=g:${group_id}+AND+a:${artifact_id}&core=gav&rows=500&wt=json" | jq -r '.response.docs[] | select(.v | test("^[0-9]+(\\.[0-9]+)*$")) | .v' | sort -V | tail -n 1)
+    echo "${latest}"
+}
+
+# Update a key to a new value in the generation config.
+function update_config() {
+    local key_word=$1
+    local new_value=$2
+    local file=$3
+    echo "Update ${key_word} to ${new_value} in ${file}"
+    sed -i -e "s/^${key_word}.*$/${key_word}: ${new_value}/" "${file}"
+}
+
+# The parameters of this script is:
+# 1. base_branch, the base branch of the result pull request.
+# 2. repo, organization/repo-name, e.g., googleapis/google-cloud-java
+# 3. [optional] generation_config, the path to the generation configuration,
+# the default value is generation_config.yaml in the repository root.
+while [[ $# -gt 0 ]]; do
+key="$1"
+case "${key}" in
+  --base_branch)
+    base_branch="$2"
+    shift
+    ;;
+  --repo)
+    repo="$2"
+    shift
+    ;;
+  --generation_config)
+    generation_config="$2"
+    shift
+    ;;
+  *)
+    echo "Invalid option: [$1]"
+    exit 1
+    ;;
+esac
+shift
+done
+
+if [ -z "${base_branch}" ]; then
+  echo "missing required argument --base_branch"
+  exit 1
+fi
+
+if [ -z "${repo}" ]; then
+  echo "missing required argument --repo"
+  exit 1
+fi
+
+if [ -z "${generation_config}" ]; then
+  generation_config="generation_config.yaml"
+  echo "Use default generation config: ${generation_config}"
+fi
+
+current_branch="generate-libraries-${base_branch}"
+title="chore: Update generation configuration at $(date)"
+
+# try to find a open pull request associated with the branch
+pr_num=$(gh pr list -s open -H "${current_branch}" -q . --json number | jq ".[] | .number")
+# create a branch if there's no open pull request associated with the
+# branch; otherwise checkout the pull request.
+if [ -z "${pr_num}" ]; then
+  git checkout -b "${current_branch}"
+else
+  gh pr checkout "${pr_num}"
+fi
+
+mkdir tmp-googleapis
+# use partial clone because only commit history is needed.
+git clone --filter=blob:none https://github.com/googleapis/googleapis.git tmp-googleapis
+pushd tmp-googleapis
+git pull
+latest_commit=$(git rev-parse HEAD)
+popd
+rm -rf tmp-googleapis
+update_config "googleapis_commitish" "${latest_commit}" "${generation_config}"
+
+# update gapic-generator-java version to the latest
+latest_version=$(get_latest_released_version "com.google.api" "gapic-generator-java")
+update_config "gapic_generator_version" "${latest_version}" "${generation_config}"
+
+# update libraries-bom version to the latest
+latest_version=$(get_latest_released_version "com.google.cloud" "libraries-bom")
+update_config "libraries_bom_version" "${latest_version}" "${generation_config}"
+
+git add "${generation_config}"
+changed_files=$(git diff --cached --name-only)
+if [[ "${changed_files}" == "" ]]; then
+    echo "The latest generation config is not changed."
+    echo "Skip committing to the pull request."
+    exit 0
+fi
+git commit -m "${title}"
+if [ -z "${pr_num}" ]; then
+  git remote add remote_repo https://cloud-java-bot:"${GH_TOKEN}@github.com/${repo}.git"
+  git fetch -q --unshallow remote_repo
+  git push -f remote_repo "${current_branch}"
+  gh pr create --title "${title}" --head "${current_branch}" --body "${title}" --base "${base_branch}"
+else
+  git push
+  gh pr edit "${pr_num}" --title "${title}" --body "${title}"
+fi

.github/workflows/hermetic_library_generation.yaml

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+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# GitHub action job to test core java library features on
+# downstream client libraries before they are released.
+name: Hermetic library generation upon generation config change through pull requests
+on:
+  pull_request:
+
+jobs:
+  library_generation:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        token: ${{ secrets.CLOUD_JAVA_BOT_TOKEN }}
+    - name: Generate changed libraries
+      shell: bash
+      run: |
+        set -x
+        [ -z "$(git config user.email)" ] && git config --global user.email "cloud-java-bot@google.com"
+        [ -z "$(git config user.name)" ] && git config --global user.name "cloud-java-bot"
+        bash .github/scriptes/hermetic_library_generation.sh \
+          --target_branch ${{ github.base_ref }} \
+          --current_branch ${{ github.head_ref }}
+      env:
+        GH_TOKEN: ${{ secrets.CLOUD_JAVA_BOT_TOKEN }}

.github/workflows/update_generation_config.yaml

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+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# GitHub action job to test core java library features on
+# downstream client libraries before they are released.
+name: Update generation configuration
+on:
+  schedule:
+  - cron: '0 2 * * *'
+  workflow_dispatch:
+
+jobs:
+  update-generation-config:
+    runs-on: ubuntu-22.04
+    env:
+      # the branch into which the pull request is merged
+      base_branch: main
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        token: ${{ secrets.CLOUD_JAVA_BOT_TOKEN }}
+    - name: Update params in generation config to latest
+      shell: bash
+      run: |
+        set -x
+        [ -z "$(git config user.email)" ] && git config --global user.email "cloud-java-bot@google.com"
+        [ -z "$(git config user.name)" ] && git config --global user.name "cloud-java-bot"
+        bash .github/scripts/update_generation_config.sh \
+          --base_branch "${base_branch}"\
+          --repo ${{ github.repository }}
+      env:
+        GH_TOKEN: ${{ secrets.CLOUD_JAVA_BOT_TOKEN }}

generation_config.yaml

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+gapic_generator_version: 2.42.0
+googleapis_commitish: 6f289d775912966eb0cf04bda91e5e355c998d30
+libraries_bom_version: 26.38.0
+libraries:
+  - api_shortname: pubsub
+    name_pretty: Cloud Pub/Sub
+    api_reference: https://cloud.google.com/java/docs/reference/google-cloud-pubsub/latest/com.google.cloud.pubsub.v1
+    product_documentation: https://cloud.google.com/pubsub/docs/
+    client_documentation: https://cloud.google.com/java/docs/reference/google-cloud-pubsub/latest
+    api_description: is designed to provide reliable, many-to-many, asynchronous messaging between applications. Publisher applications can send messages to a topic and other applications can subscribe to that topic to receive the messages. By decoupling senders and receivers, Google Cloud Pub/Sub allows developers to communicate between independently written applications.
+    issue_tracker: https://issuetracker.google.com/savedsearches/559741
+    release_level: stable
+    language: java
+    repo: googleapis/java-pubsub
+    repo_short: java-pubsub
+    distribution_name: com.google.cloud:google-cloud-pubsub
+    codeowner_team: '@googleapis/api-pubsub'
+    api_id: pubsub.googleapis.com
+    library_type: GAPIC_COMBO
+    requires_billing: true
+    recommended_package: com.google.cloud.pubsub.v1
+    GAPICs:
+      - proto_path: google/pubsub/v1