GoogleCloudPlatform · coryan · Feb 8, 2021 · Feb 8, 2021 · devbww · Feb 8, 2021
@@ -33,6 +33,7 @@ https://cloud.google.com/run/docs/quickstarts/build-and-deploy
 [quickstart-local]: /examples/site/howto_local_development/README.md
 [quickstart-container]: /examples/site/howto_create_container/README.md
 [quickstart-cloud-run]: /examples/site/howto_deploy_to_cloud_run/README.md
+[quickstart-pubsub]: /examples/site/howto_deploy_cloud_event/README.md
 
 > :warning: This is not ready for production. Expect breaking changes.
 > We're sharing our progress with the developer community and appreciate

@@ -0,0 +1,188 @@
+# How-to Guide: Deploy a C++ Pub/Sub function to Cloud Run
+
+[repository-gh]: https://github.com/GoogleCloudPlatform/functions-framework-cpp
+[howto-create-container]: /examples/site/howto_create_container/README.md
+[cloud-run-quickstarts]: https://cloud.google.com/run/docs/quickstarts
+[gcp-quickstarts]: https://cloud.google.com/gcp/getting-started
+[buildpacks]: https://buildpacks.io
+[docker-install]: https://store.docker.com/search?type=edition&offering=community
+[pack-install]: https://buildpacks.io/docs/install-pack/
+[hello-world-pubsub]: /examples/site/hello_world_pubsub/hello_world_pubsub.cc
+[gcloud-eventarc-create]: https://cloud.google.com/sdk/gcloud/reference/beta/eventarc/triggers/create
+
+## Pre-requisites
+
+This guide assumes you are familiar with Google Cloud, and that you have a GCP
+project with Cloud Run enabled. If needed, consult:
+* the [GCP quickstarts][gcp-quickstarts] to setup a GCP project
+* the [cloud run quickstarts][cloud-run-quickstarts] to setup Cloud Run in your
+  project
+
+This guide also assumes that you have installed [Docker][docker-install] and
+the [pack tool][pack-install] on your workstation.
+
+In this guide we will be using the [Pub/Sub hello word][hello-world-pubsub] function:
+
+```cc
+namespace gcf = ::google::cloud::functions;
+
+// Use Boost.Archive to decode Pub/Sub message payload
+std::string decode_base64(std::string const& base64);
+
+void hello_world_pubsub(gcf::CloudEvent event) {  // NOLINT
+  if (event.data_content_type().value_or("") != "application/json") {
+    std::cerr << "Error: expected application/json data\n";
+    return;
+  }
+  auto const payload = nlohmann::json::parse(event.data().value_or("{}"));
+  auto name = decode_base64(payload["message"]["data"].get<std::string>());
+  BOOST_LOG_TRIVIAL(info) << "Hello " << (name.empty() ? "World" : name);
+}
+```
+
+## Getting the code for this example
+
+This example is included in the Functions Framework for C++
+[source code repository][repository]. Download this code as usual:
+
+```shell
+cd $HOME
+git clone https://github.com/GoogleCloudPlatform/functions-framework-cpp
+```
+
+The rest of this guide will assume you are issuing commands in the framework's
+clone:
+
+```shell
+cd $HOME/functions-framework-cpp
+```
+
+## Setting up the buildpacks builder
+
+We will be using a [buildpacks][buildpacks] builder to create the container
+image deployed to Cloud Run. The first time your run these commands it can take
+several minutes, maybe as long as an hour, depending on your workstation's
+performance.
+
+```sh
+docker build -t gcf-cpp-develop -f build_scripts/Dockerfile .
+docker build -t gcf-cpp-runtime --target gcf-cpp-runtime -f build_scripts/Dockerfile build_scripts
+pack create-builder gcf-cpp-builder:bionic --config pack/builder.toml
+pack trust-builder gcf-cpp-builder:bionic
+pack set-default-builder gcf-cpp-builder:bionic
+```
+
+## Building a Docker image
+
+Set the `GOOGLE_CLOUD_PROJECT` shell variable to the project id of your GCP
+project, and create a docker image with your function:
+
+```shell
+GOOGLE_CLOUD_PROJECT=... # put the right value here
+pack build \
+   --builder gcf-cpp-builder:bionic \
+   --env FUNCTION_SIGNATURE_TYPE=cloudevent \
+   --env TARGET_FUNCTION=hello_world_pubsub \
+   --path examples/site/hello_world_pubsub \
+   "gcr.io/${GOOGLE_CLOUD_PROJECT}/gcf-cpp-hello-world-pubsub"
+```
+
+Push this new container image to Google Container Registry:
+
+```shell
+docker push "gcr.io/${GOOGLE_CLOUD_PROJECT}/gcf-cpp-hello-world-pubsub:latest"
+```
+
+## Deploy to Cloud Run
+
+To deploy this image in Cloud Run use this command. You need to select
+a Cloud Run region for your deployment. We will use `us-central1` in this
+guide:
+
+```shell
+gcloud run deploy gcf-cpp-hello-world-pubsub \
+    --project="${GOOGLE_CLOUD_PROJECT}" \
+    --image="gcr.io/${GOOGLE_CLOUD_PROJECT}/gcf-cpp-hello-world-pubsub:latest" \
+    --region="us-central1" \
+    --platform="managed" \
+    --allow-unauthenticated
+```
+
+Verify unauthenticated requests are allowed:
+
+```shell
+gcloud run services get-iam-policy gcf-cpp-hello-world-pubsub \
+     --project="${GOOGLE_CLOUD_PROJECT}" \
+     --region="us-central1" \
+     --platform="managed"
+```
+
+The result should include `allUsers`.
+
+> :warning: It is possible your organization has disabled unauthenticated
+> requests to Cloud Run. If this is the case the rest of this guide will not
+> work, as `eventarc` only supports unauthenticated connections at this time.
+
+## Setup a Pub/Sub trigger
+
+An eventarc trigger receives events from Pub/Sub and forward them to your
+function in the correct format. For simplicity, this guide will create create a
+new topic as part of setting up the trigger. If you prefer to use an existing
+topic read about the the `--topic-transport` option in the
+[gcloud documentation][gcloud-eventarc-create]. Once you have decided how to
+proceed run this command (maybe with an addition `--topic-transport` option):
+
+```shell
+gcloud beta eventarc triggers create gcf-cpp-hello-world-pubsub-trigger \
+    --project="${GOOGLE_CLOUD_PROJECT}" \
+    --location="us-central1" \
+    --destination-run-service="gcf-cpp-hello-world-pubsub" \
+    --destination-run-region="us-central1" \
+    --matching-criteria="type=google.cloud.pubsub.topic.v1.messagePublished"
+```
+
+Find out what topic is used to this new trigger:
+
+```shell
+TOPIC=$(gcloud beta eventarc triggers describe gcf-cpp-hello-world-pubsub-trigger \
+    --project="${GOOGLE_CLOUD_PROJECT}" \
+    --location="us-central1" \
+    --format="value(transport.pubsub.topic)")
+```
+
+## Publish a Pub/Sub and verify your function receives it
+
+Use the following `gcloud` to publish a message
+
+```shell
+gcloud pubsub topics publish "${TOPIC}" --message="Event"
+```
+
+CloudEvent functions produce no responses, but you can examine their log
+to verify the Pub/Sub message was received:
+
+```shell
+gcloud logging read \
+    --project="${GOOGLE_CLOUD_PROJECT}" \
+    --format="value(textPayload)" \
+    "resource.type=cloud_run_revision AND resource.labels.service_name=gcf-cpp-hello-world-pubsub AND logName:stdout"
+# Output: Hello Event
+```
+
+## Cleanup
+
+Delete the Cloud Run deployment:
+
+```sh
+gcloud run services delete gcf-cpp-hello-world-pubsub \
+    --project="${GOOGLE_CLOUD_PROJECT}" \
+    --region="us-central1" \
+    --platform="managed"
+```
+
+And the container image:
+
+```shell
+gcloud container images delete \
+    "gcr.io/${GOOGLE_CLOUD_PROJECT}/gcf-cpp-hello-world-pubsub:latest"
+```