genai: improve code generation command (#144)

Use the cached directory for the right version of the pb.go files.
This ensures that the generated code matches the version of
cloud.google.com/go/ai in the go.mod file, rather than whatever
happens to be checked out in the google-cloud-go repo.

genai/client.go

@@ -12,23 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// For the following go:generate line to work, do the following:
-// Install the protoveener tool:
+// For the following go:generate line to work, install the protoveener tool:
 //    git clone https://github.com/googleapis/google-cloud-go
 //    cd google-cloud-go
 //    go install ./internal/protoveneer/cmd/protoveneer
 //
-// Set the environment variable GOOGLE_CLOUD_GO to the path to the above repo on your machine.
-// For example:
-//     export GOOGLE_CLOUD_GO=$HOME/repos/google-cloud-go
-//
-// Ensure that the working directory of that repo is at the version of cloud.google.com/go/ai in
-// this repo's go.mod file. For example, if the go.mod contains
-//   cloud.google.com/go/ai v0.6.0
-// then from the root of the google-cloud-go repo, run
-//   git switch -d ai/v0.6.0
-
-//go:generate protoveneer -license license.txt config.yaml $GOOGLE_CLOUD_GO/ai/generativelanguage/apiv1beta/generativelanguagepb
+//go:generate ./generate.sh
 
 package genai
 

genai/generate.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+# Copyright 2023 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.
+
+version=$(awk '$1 == "cloud.google.com/go/ai" {print $2}' ../go.mod)
+
+if [[ $version = '' ]]; then
+  echo >&2 "could not get version of cloud.google.com/go/ai from ../go.mod"
+  exit 1
+fi
+
+dir=~/go/pkg/mod/cloud.google.com/go/ai@$version/generativelanguage/apiv1beta/generativelanguagepb
+
+if [[ ! -d $dir ]]; then
+  echo >&2 "$dir does not exist or is not a directory"
+  exit 1
+fi
+
+echo "generating from $dir"
+protoveneer -license license.txt config.yaml $dir
+