README
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Building, Testing, and Optimizing Code on the Google Cloud
This example demonstrates a web app that sends messages from a user to their friends. It demonstrates the use of Google Cloud Build for building and testing portable Go code with an application that can be run locally, in unit tests, in App Engine Flex, and a Docker container.
Project Setup
The prerequisites for running the example locally are
If you prefer not to install gcloud and Docker locally you can use Google Cloud Shell.
To run this example, you will need to create a Google Cloud project with billing enabled. You will also need to enable the following APIs
Set your project as the default in your local development environment with the command
PROJECT_ID=[Your project id]
gcloud config set project $PROJECT_ID
Get the example code and artifacts with the command
git clone https://github.com/GoogleCloudPlatform/golang-samples.git
cd go/src/github.com/GoogleCloudPlatform/golang-samples/getting-started/devflowapp
Local development, mocks, and unit testing
You can run locally and unit test using a mock of the MessageService
interface.
Running locally
To use a mock database when running the app locally, run::
export MESSAGE_SERVICE=mock
go get -d -v ./...
go run devflowapp.go
Check that the application successfully responds to a HTTP request:
curl -I http://localhost:8080
You can also use Curl to send a message to your friend a message, like
curl "http://localhost:8080/send?user=Friend1&friend=Friend2&text=We+miss+you!"
Your friend can also check their messages with a URL like:
curl "http://localhost:8080/messages?user=Friend2"
With a mock service we lose the messages as soon as the app is stopped. Unset the environment variable for use of mocks with the command
unset MESSAGE_SERVICE
Unit tests
To run unit tests use the two commands, for each of the main and services packages:
go test
go test -v github.com/GoogleCloudPlatform/golang-samples/getting-started/devflowapp/services
Check that the tests pass. The Go httptest package is used to simulate HTTP requests and writers in some of the unit tests.
To use Cloud Build, run the build and execute unit tests using Cloud Build
gcloud builds submit --config build/cb-unittest.yaml .
View the build and test results in the cloud console under the Cloud Build menu.
Database
Setup
This section is based on the instructions at Using Cloud SQL with Go.
Create a Second Generation Cloud SQL instance using the commands below, naming the instance 'devflowapp'.
INSTANCE_NAME=devflowapp
MACHINE_TYPE=db-n1-standard-1
REGION=us-central1
gcloud sql instances create $INSTANCE_NAME --tier=$MACHINE_TYPE \
--region=$REGION
To set the root password, use the cloud console or the command
gcloud sql users set-password root % --instance devflowapp --password [PASSWORD]
To see the connection details for your instance use the command
gcloud sql instances describe $INSTANCE_NAME
Look for the connectionName, which as the form
$PROJECT:$REGION:$INSTANCE_NAME.
Also, look for the IP address of the instance.
Connect to the your Cloud SQL instance with the command in the Cloud Shell
INSTANCE_NAME=devflowapp
gcloud sql connect $INSTANCE_NAME --user=root
Execute the statements in data/database_setup.sql.
Working with the Database in a Local Development Environment (Optional)
To install the Cloud SQL proxy locally follow Using Cloud SQL with Go, for example on Mac, use the commands
curl -o cloud_sql_proxy https://dl.google.com/cloudsql/cloud_sql_proxy.darwin.386
chmod +x cloud_sql_proxy
Start the proxy with the commands
PROJECT_ID=[your project]
REGION=[your region]
CONNECTION_NAME=$PROJECT_ID:$REGION:$INSTANCE_NAME
./cloud_sql_proxy -instances="$CONNECTION_NAME"=tcp:3306
Run the web app in a separate terminal
DBPASSWORD=[your password]
DBUSER=proxyuser
DBHOST=127.0.0.1
DATABASE=messagesdb
export MYSQL_CONNECTION="$DBUSER:$DBPASSWORD@tcp($DBHOST:3306)/$DATABASE"
go run devflowapp.go
You can now use the same Curl commands as above to send your friend a message.
Packaging in a Docker Container
The devflowapp example can package your application in a Docker container based on the golang image, with the commands
docker build -f Dockerfile -t devflowapp-image .
docker run -itd --rm --name devflowapp \
-p 8080:8080 \
--env MESSAGE_SERVICE=mock \
devflowapp-image
This will run the container with the mock messaging service. We will describe how to configure the app to connect to Cloud SQL below.
Check that the application is running OK use the same Curl commands as above.
Stop the app with the command
docker stop devflowapp
Build the Docker container with Cloud Build:
gcloud builds submit --config build/cb-docker.yaml .
Run in Docker, test that it works, and stop it
gcloud auth configure-docker
PROJECT_ID=[your project]
docker run -itd --rm -p 8080:8080 \
--name devflowapp \
--env MESSAGE_SERVICE=mock \
gcr.io/$PROJECT_ID/devflowapp
docker ps
curl -I http://localhost:8080
docker stop devflowapp
Deploy the app to App Engine Flexible
If you have not used App Engine in your project before you will need to enable it. You can do that with the command
gcloud app create --region=us-central
To deploy the app to Flex with the database dependency mocked out use the command
gcloud app deploy app-mock.yaml
Check that the app is being served by App Engine with the command
gcloud app browse
To run the app together with the Cloud SQL database follow steps as in Using Cloud SQL for MySQL for Flex. You can do this by editing the app.yaml file then filling in the text for the password and the project id. Then redeploy the app using the command
gcloud app deploy .
To do the equivalent operation in Cloud Build, follow the steps in Deploying artifacts. In particular, you will need to grant App Engine Admin role to the Cloud Build service account.
You will want to avoid leaving the project id and password in the app configuration file, especially if you are adding the file to a code repository. Revert the values back to their original symbols by editing app.yaml. To deploy with Cloud Build, set the strings as environment variables using the command
DB_PASSWORD=[user db password]
gcloud builds submit \
--substitutions=_DB_PASSWORD=$DB_PASSWORD \
--config build/cb-deploy.yaml .
The build/cb-deploy.yaml file contains a custom build step with shell commands to replace the connection string settings in app.yaml with user defined substitutions.
Check that the app is being served by App Engine by pointing your browser at $PROJECT_ID.appspot.com.
curl -I $PROJECT_ID.appspot.com
Integration and Load Testing
An integration test uses Curl to make sure that the application is properly configured to talk to the database and test cases for sending and retrieving messages are working ok end-to-end.
gcloud builds submit --config build/cb-e2etest.yaml .
More
For more on Google Cloud Build see the recording of the Cloud Build documentation page. Also see the Go Bookshelf example app for the use of a number of storage options with Go.
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