feat: generate proto-only library (#2046)

* feat: generate non-gapic library

* change parameter to `proto_only`

* add doc for `proto_only`

* change comments

* add proto-only library in integration test

library_generation/README.md

@@ -91,6 +91,17 @@ Use `--grpc_version` to specify the value.
 
 Note that if specified, the version should be compatible with gapic-generator-java.
 
+### proto_only (optional)
+Whether this is a proto-only library (no `gapic-*` directory in the generated 
+library).
+The default value is `false`.
+
+When set to `true`, the GAPIC generator will not be invoked.
+Therefore, GAPIC options (`transport`, `rest_numeric_enums`) and 
+`gapic_additional_protos` will be ignored.
+
+Use `--proto_only` to specify the value.
+
 ### gapic_additional_protos (optional)
 Additional protos that pass to the generator.
 The default value is `google/cloud/common_resources.proto`.

library_generation/generate_library.sh

@@ -29,6 +29,10 @@ case $key in
     grpc_version="$2"
     shift
     ;;
+  --proto_only)
+    proto_only="$2"
+    shift
+    ;;
   --gapic_additional_protos)
     gapic_additional_protos="$2"
     shift
@@ -69,6 +73,10 @@ if [ -z "${grpc_version}" ]; then
   grpc_version=$(get_grpc_version "${gapic_generator_version}")
 fi
 
+if [ -z "${proto_only}" ]; then
+  proto_only="false"
+fi
+
 if [ -z "${gapic_additional_protos}" ]; then
   gapic_additional_protos="google/cloud/common_resources.proto"
 fi
@@ -120,43 +128,46 @@ fi
 ###################### Section 2 #####################
 ## generate gapic-*/, part of proto-*/, samples/
 ######################################################
-"$protoc_path"/protoc --experimental_allow_proto3_optional \
-"--plugin=protoc-gen-java_gapic=${script_dir}/gapic-generator-java-wrapper" \
-"--java_gapic_out=metadata:${destination_path}/java_gapic_srcjar_raw.srcjar.zip" \
-"--java_gapic_opt=$(get_gapic_opts)" \
-${proto_files} ${gapic_additional_protos}
+if [[ "${proto_only}" == "false" ]]; then
+  "$protoc_path"/protoc --experimental_allow_proto3_optional \
+  "--plugin=protoc-gen-java_gapic=${script_dir}/gapic-generator-java-wrapper" \
+  "--java_gapic_out=metadata:${destination_path}/java_gapic_srcjar_raw.srcjar.zip" \
+  "--java_gapic_opt=$(get_gapic_opts)" \
+  ${proto_files} ${gapic_additional_protos}
 
-unzip -o -q "${destination_path}/java_gapic_srcjar_raw.srcjar.zip" -d "${destination_path}"
-# Sync'\''d to the output file name in Writer.java.
-unzip -o -q "${destination_path}/temp-codegen.srcjar" -d "${destination_path}/java_gapic_srcjar"
-# Resource name source files.
-proto_dir=${destination_path}/java_gapic_srcjar/proto/src/main/java
-if [ ! -d "${proto_dir}" ]; then
-  # Some APIs don'\''t have resource name helpers, like BigQuery v2.
-  # Create an empty file so we can finish building. Gating the resource name rule definition
-  # on file existences go against Bazel'\''s design patterns, so we'\''ll simply delete all empty
-  # files during the final packaging process (see java_gapic_pkg.bzl)
-  mkdir -p "${proto_dir}"
-  touch "${proto_dir}"/PlaceholderFile.java
-fi
-
-# move java_gapic_srcjar/src/main to gapic-*/src.
-mv_src_files "gapic" "main"
-# remove empty files in gapic-*/src/main/java
-remove_empty_files "gapic"
-# move java_gapic_srcjar/src/test to gapic-*/src
-mv_src_files "gapic" "test"
-if [ "${include_samples}" == "true" ]; then
-  # move java_gapic_srcjar/samples/snippets to samples/snippets
-  mv_src_files "samples" "main"
+  unzip -o -q "${destination_path}/java_gapic_srcjar_raw.srcjar.zip" -d "${destination_path}"
+  # Sync'\''d to the output file name in Writer.java.
+  unzip -o -q "${destination_path}/temp-codegen.srcjar" -d "${destination_path}/java_gapic_srcjar"
+  # Resource name source files.
+  proto_dir=${destination_path}/java_gapic_srcjar/proto/src/main/java
+  if [ ! -d "${proto_dir}" ]; then
+    # Some APIs don't have resource name helpers, like BigQuery v2.
+    # Create an empty file so we can finish building. Gating the resource name rule definition
+    # on file existences go against Bazel's design patterns, so we'll simply delete all empty
+    # files during the final packaging process (see java_gapic_pkg.bzl)
+    mkdir -p "${proto_dir}"
+    touch "${proto_dir}"/PlaceholderFile.java
+  fi
+  # move java_gapic_srcjar/src/main to gapic-*/src.
+  mv_src_files "gapic" "main"
+  # remove empty files in gapic-*/src/main/java
+  remove_empty_files "gapic"
+  # move java_gapic_srcjar/src/test to gapic-*/src
+  mv_src_files "gapic" "test"
+  if [ "${include_samples}" == "true" ]; then
+    # move java_gapic_srcjar/samples/snippets to samples/snippets
+    mv_src_files "samples" "main"
+  fi
 fi
 ##################### Section 3 #####################
 # generate proto-*/
 #####################################################
 "$protoc_path"/protoc "--java_out=${destination_path}/java_proto.jar" ${proto_files}
-# move java_gapic_srcjar/proto/src/main/java (generated resource name helper class)
-# to proto-*/src/main
-mv_src_files "proto" "main"
+if [[ "${proto_only}" == "false" ]]; then
+  # move java_gapic_srcjar/proto/src/main/java (generated resource name helper class)
+  # to proto-*/src/main
+  mv_src_files "proto" "main"
+fi
 # unzip java_proto.jar to proto-*/src/main/java
 unzip_src_files "proto"
 # remove empty files in proto-*/src/main/java

library_generation/test/generate_library_integration_test.sh

@@ -64,6 +64,7 @@ grep -v '^ *#' < "${proto_path_list}" | while IFS= read -r line; do
   # parse GAPIC options from proto_path/BUILD.bazel
   pushd "${output_folder}"
   proto_build_file_path="${proto_path}/BUILD.bazel"
+  proto_only=$(get_proto_only_from_BUILD "${proto_build_file_path}")
   gapic_additional_protos=$(get_gapic_additional_protos_from_BUILD "${proto_build_file_path}")
   transport=$(get_transport_from_BUILD "${proto_build_file_path}")
   rest_numeric_enums=$(get_rest_numeric_enums_from_BUILD "${proto_build_file_path}")
@@ -77,6 +78,7 @@ grep -v '^ *#' < "${proto_path_list}" | while IFS= read -r line; do
   -d "${destination_path}" \
   --gapic_generator_version "${gapic_generator_version}" \
   --protobuf_version "${protobuf_version}" \
+  --proto_only "${proto_only}" \
   --gapic_additional_protos "${gapic_additional_protos}" \
   --transport "${transport}" \
   --rest_numeric_enums "${rest_numeric_enums}" \

library_generation/test/resources/proto_path_list.txt

@@ -9,6 +9,7 @@ google/cloud/kms/v1 google-cloud-kms-v1-java
 google/cloud/redis/v1 google-cloud-redis-v1-java
 google/example/library/v1 google-cloud-example-library-v1-java
 google/devtools/containeranalysis/v1 google-cloud-devtools-containeranalysis-v1-java
+google/firestore/bundle google-cloud-firestore-bundle-v1-java
 # google/iam/v1 google-iam-v1-java
 google/iam/credentials/v1 google-cloud-iam-credentials-v1-java
 google/logging/v2 google-cloud-logging-v2-java

library_generation/test/test_utilities.sh

@@ -126,6 +126,18 @@ execute_tests() {
 }
 
 ############# Utility functions used in `generate_library_integration_tests.sh` #############
+get_proto_only_from_BUILD() {
+  local build_file=$1
+  local proto_only
+  proto_only=$(__get_config_from_BUILD \
+    "${build_file}" \
+    "java_gapic_library(" \
+    "java_gapic_library" \
+    "true" \
+    "false"
+  )
+  echo "${proto_only}"
+}
 
 # Apart from proto files in proto_path, additional protos are needed in order
 # to generate GAPIC client libraries.

library_generation/utilities.sh

@@ -11,7 +11,14 @@ extract_folder_name() {
 
 remove_empty_files() {
   local category=$1
+  local file_num
   find "${destination_path}/${category}-${folder_name}/src/main/java" -type f -size 0 | while read -r f; do rm -f "${f}"; done
+  # remove the directory if the directory has no files.
+  file_num=$(find "${destination_path}/${category}-${folder_name}" -type f | wc -l | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')
+  if [[ "${file_num}" == 0 ]]; then
+    rm -rf "${destination_path}/${category}-${folder_name}"
+  fi
+
   if [ -d "${destination_path}/${category}-${folder_name}/src/main/java/samples" ]; then
       mv "${destination_path}/${category}-${folder_name}/src/main/java/samples" "${destination_path}/${category}-${folder_name}"
   fi