examples

Testing the Functions Framework Examples

These notes describe how to build and test these examples when developing the Functions Framework for C++. The main audience for these notes are developers of this project.

• If you are looking for examples on how to use the Functions Framework for C++, the How-to Guides should help you get started.
• If you are looking for more detailed instructions to configure the CI environment, please see the Configuring the CI Environment guide.
• If you are a developer in the project and want to test how your changes affect the examples, this is the document you should read.

Create the Development and Runtime Docker Images

These notes assume the reader is familiar with GCP, the Google Cloud SDK command-line tool, and with the docker(1) command-line tool.

To compile the examples you will need a Docker image with the development tools and core dependencies pre-compiled. To create this image run this command:

docker build -t ci-build-image --target gcf-cpp-ci -f build_scripts/Dockerfile .

The runtime image is contains just the minimal components to execute a program using the framework:

docker build -t ci-run-image --target gcf-cpp-runtime -f build_scripts/Dockerfile build_scripts

Create the buildpack builder

We use buildpacks to compile the functions into runnable Docker images. First create a builder:

pack builder create gcf-cpp-builder:bionic --config ci/pack/builder.toml
pack config trusted-builders add gcf-cpp-builder:bionic

To avoid using the --builder gcf-cpp-builder:bionic option in each command we make this builder the default:

pack config default-builder gcf-cpp-builder:bionic

Creating a Docker image for the examples

Compile any HTTP example using:

pack build "my-image" \
  --env GOOGLE_FUNCTION_TARGET=$EXAMPLE_FUNCTION_NAME \
  --env GOOGLE_FUNCTION_SIGNATURE_TYPE=http \
  --path examples/$EXAMPLE_DIRECTORY

for example:

pack build "hello-world" \
  --env GOOGLE_FUNCTION_TARGET=HelloWorld \
  --env GOOGLE_FUNCTION_SIGNATURE_TYPE=http \
  --path examples/hello_world

and then run the image as usual:

ID=$(docker run --detach --publish 8080:8080 hello-world)
curl http://localhost:8080/
docker kill ${ID}

Deploying to Cloud Run

This example assumes that GOOGLE_CLOUD_PROJECT is set to a GCP project with the right services enabled:

GOOGLE_CLOUD_PROJECT=...          # use a real project
GOOGLE_CLOUD_REGION=us-central1   # use a different region if desired 

Create the Docker image, with a tag suitable for deployment to Cloud Run:

pack build "gcr.io/${GOOGLE_CLOUD_PROJECT}/hello-world" \
  --env GOOGLE_FUNCTION_TARGET=HelloWorld \
  --env GOOGLE_FUNCTION_SIGNATURE_TYPE=http \
  --path examples/hello_world

Push this image to Google Container Registry:

docker push gcr.io/${GOOGLE_CLOUD_PROJECT}/hello-world:latest

Deploy this application to Cloud Run:

gcloud run deploy gcf-cpp-hello \
    "--project=${GOOGLE_CLOUD_PROJECT}" \
    "--image=gcr.io/${GOOGLE_CLOUD_PROJECT}/hello-world:latest" \
    "--region=${GOOGLE_CLOUD_REGION}" \
    "--platform=managed" \
    "--no-allow-unauthenticated"

Fetch the service URL:

SERVICE_URL=$(gcloud run services list \
    "--project=${GOOGLE_CLOUD_PROJECT}" \
    "--platform=managed" \
    '--format=csv[no-heading](URL)' \
    "--filter=SERVICE:gcf-cpp-hello")

Test by sending a request using curl:

curl -H "Authorization: Bearer $(gcloud auth print-identity-token)" "${SERVICE_URL}"