This repo contains the Go source code for a simple web app that can be deployed to App Engine Standard. It is a demonstration of how to connect to a SQL Server instance in Cloud SQL. The application is the "Tabs vs Spaces" web app used in the Building Stateful Applications With Kubernetes and Cloud SQL session at Cloud Next '19.

1. If you haven't already, set up a Go Development Environment by following the Go setup guide and create a project.

2. Create a Cloud SQL for SQL Server instance by following these instructions. Note the connection string, database user, and database password that you create.

3. Create a database for your application by following these instructions. Note the database name.

4. Set up Application Default Credentials and ensure you have added the 'Cloud SQL Client' role to your IAM principal.

To run this application locally, download and install the cloud_sql_proxy by following the instructions here.

Instructions are provided below for using the proxy with a TCP connection or a Unix Domain Socket. On Linux or Mac OS you can use either option, but on Windows the proxy currently requires a TCP connection.

To run the sample locally with a TCP connection, set environment variables and launch the proxy as shown below.

Use these terminal commands to initialize environment variables:

export INSTANCE_HOST='127.0.0.1'
export DB_PORT='1433'
export DB_USER='<YOUR_DB_USER_NAME>'
export DB_PASS='<YOUR_DB_PASSWORD>'
export DB_NAME='<YOUR_DB_NAME>'

Then use this command to launch the proxy in the background:

./cloud-sql-proxy <PROJECT-ID>:<INSTANCE-REGION>:<INSTANCE-NAME> --port=1433 &

Use these PowerShell commands to initialize environment variables:

$env:INSTANCE_HOST="127.0.0.1"
$env:DB_PORT="1433"
$env:DB_USER="<YOUR_DB_USER_NAME>"
$env:DB_PASS="<YOUR_DB_PASSWORD>"
$env:DB_NAME="<YOUR_DB_NAME>"

Then use this command to launch the proxy in a separate PowerShell session:

Start-Process -filepath "C:\<path to proxy exe>" -ArgumentList "<PROJECT-ID>:<INSTANCE-REGION>:<INSTANCE-NAME> --port=1433"

To test the application locally, follow these steps after the proxy is running:

• Install dependencies: go get ./...
• Run the application: go run cloudsql.go
• Navigate to http://127.0.0.1:8080 in a web browser to verify your application is running correctly.

To run the sample on GAE-Standard, create an App Engine project by following the setup for these instructions.

First, update app.standard.yaml with the correct values to pass the environment variables into the runtime. Your app.standard.yaml file should look like this:

runtime: go116
env_variables:
  INSTANCE_CONNECTION_NAME: <PROJECT-ID>:<INSTANCE-REGION>:<INSTANCE-NAME>
  DB_USER: <YOUR_DB_USER_NAME>
  DB_PASS: <YOUR_DB_PASSWORD>
  DB_NAME: <YOUR_DB_NAME>

Note: Saving credentials in environment variables is convenient, but not secure - consider a more secure solution such as Cloud KMS to help keep secrets safe.

Next, the following command will deploy the application to your Google Cloud project:

gcloud app deploy cmd/app/app.standard.yaml

To run the sample on GAE-Flex, create an App Engine project by following the setup for these instructions.

First, update app.flexible.yaml with the correct values to pass the environment variables into the runtime. Your app.flexible.yaml file should look like this:

runtime: custom
env: flex

env_variables:
  INSTANCE_CONNECTION_NAME: <PROJECT-ID>:<INSTANCE-REGION>:<INSTANCE-NAME>
  DB_USER: <YOUR_DB_USER_NAME>
  DB_PASS: <YOUR_DB_PASSWORD>
  DB_NAME: <YOUR_DB_NAME>

beta_settings:
  cloud_sql_instances: <PROJECT-ID>:<INSTANCE-REGION>:<INSTANCE-NAME>

Note: Saving credentials in environment variables is convenient, but not secure - consider a more secure solution such as Cloud Secret Manager to help keep secrets safe.

Next, the following command will deploy the application to your Google Cloud project:

gcloud app deploy app.flexible.yaml

To deploy the service to Cloud Functions run the following command:

gcloud functions deploy votes --gen2 --runtime go120 --trigger-http \
  --allow-unauthenticated \
  --entry-point Votes \
  --region <INSTANCE_REGION> \
  --set-env-vars INSTANCE_CONNECTION_NAME=<PROJECT_ID>:<INSTANCE_REGION>:<INSTANCE_NAME> \
  --set-env-vars DB_USER=$DB_USER \
  --set-env-vars DB_PASS=$DB_PASS \
  --set-env-vars DB_NAME=$DB_NAME

Take note of the URL output at the end of the deployment process to view your function!