your-diary / gcp_samples

1. About

Sample Go projects to access GCP via SDK.

2. Prerequisites

Nothing.

3. ./cloud_functions/ project

3.1 About

This project creates a REST API which receives a JSON of the form {"content": <string>} and uploads its content as <timestamp>.txt to Cloud Storage. A signed URL (i.e. a public URL with expiration date) to access the object uploaded in Cloud Storage is returned.

3.2 Architecture

3.3 Usage

1. Access IAM & Admin console.

   1. Select IAM in the sidebar.

   2. Click the edit icon for the principal whose value of Name field is Compute Engine default service account.

   3. Select ADD ANOTHER ROLE to add Service Account Token Creator role.

2. Access Cloud Storage console to created a bucket named test-bucket-001-a.

3. Access Cloud Functions console to create a function with the following settings.

   • Function name: function-1

   • Environment: 2nd gen

   • Region: us-central1

   • Runtime: Go 1.20

4. Upload this project to deploy a function.

   $ gcloud functions deploy function-1 --source . --gen2 --region us-central1

5. Privately test the API. (At this time, the API is not public so we need Authorization header.)

   $ curl <URL> \
       -H "Authorization: bearer $(gcloud auth print-identity-token)" \
       -H "Content-Type: application/json" \
       -d '{"content": "hello"}'

   {
       "status": "success",
       "url": "https://..."
   }

   $ curl <returned URL>

6. Access API Gateway console and select CREATE GATEWAY to create a gateway. For API Spec, upload ./cloud_functions/openapi.yaml.

7. Now the API is public via API Gateway URL. Call the API.

   $ curl <URL> \
       -H "Content-Type: application/json" \
       -d '{"content": "hello"}'

   {
       "status": "success",
       "url": "https://..."
   }

   $ curl <returned URL>

3.4 References

• GoogleCloudPlatform / functions-framework-go

• GoogleCloudPlatform / golang-samples

4. ./cloud_run/ project

4.1 About

This project deploys a very simple Docker container to Cloud Run.

4.2 Architecture

4.3 Usage

1. Interactively build and deploy Dockerfile. Allow unauthenticated invocations to issue a public URL.

   $ gcloud run deploy

   Allow unauthenticated invocations to [cloudrun] (y/N)?  y
   

2. Check the public URL of the deployment.

   $ gcloud run services list

3. Call the API.

   $ curl <URL>

   Working.
   

5. ./compute_engine/ project

5.1 About

This project creates a REST API which receives a JSON of the form {"content": <string>} and uploads its content as <timestamp>.txt to Cloud Storage. A signed URL (i.e. a public URL with expiration date) to access the object uploaded in Cloud Storage is returned. In addition, every request is logged to SQL (PostgresSQL) and Firestore.

5.2 Architecture

5.3 Usage

1. Access Firestore console.

   1. If this is the very first time you visit the console, you may be requested to select Native mode or Datastore mode. Select Native.

   2. You don't have to manually create any collection as it will be automatically created when accessed via SDK.

2. Access SQL console.

   1. Select CREATE INSTANCE.

   2. Choose PostgresSQL.

   3. Create an instance named test-sql-001.

   4. Select Connections in the sidebar.

   5. Select ADD NETWORK to add a network and specify your IP address plus assign Private IP.

3. Create a database in the SQL instance.

   1. Connect.

      $ PGPASSWORD=<password> psql -h <URL> -p 5432 -U postgres

   2. Create a database named test.

      CREATE DATABASE test;
      

   3. Check the result by listing all the databases.

      \list
      

   4. Optionally change the password.

      ALTER USER postgres PASSWORD '<new password>';
      

4. Access Compute Engine console.

   1. Select CREATE INSTANCE to create an instance named instance-2. Select Allow full access to all Cloud APIs for Access scopes. (To edit the value of Access scopes after creating the instance, first it shall be stopped.)

   2. Create a SSH key.

      $ gcloud compute ssh instance-2

   3. Connect to the instance via SSH.

      $ ssh gcp

   4. Install some packages.

      $ sudo apt update
      $ sudo apt install rsync screen

   5. Install Go by following the official instructions.

      $ curl -L -O 'https://go.dev/dl/go1.20.2.linux-amd64.tar.gz'
      $ sudo tar -C /usr/local -xzf go1.20.2.linux-amd64.tar.gz
      $ echo 'export PATH=$PATH:/usr/local/go/bin' >> ~/.profile

5. Access VPC network console.

   1. Select Firewall in the sidebar.

   2. Select CREATE FIREWALL RULE to create a rule which opens 8080 port.

6. Send this project to the instance.

   $ rsync -auv ./compute_engine gcp:./

7. Run the server.

   1. Connect to the instance.

      $ ssh gcp

   2. Build.

      $ cd compute_engine/
      $ go build main.go

   3. Write a config file (see below for the details).

      $ vi config.json

   4. Run the server.

      $ screen -d -m ./main
      $ screen -ls

8. Call the API.

   $ curl <URL>:8080 -d '{"content": "hello"}'

   {
       "status": "success",
       "url": "https://..."
   }

   $ curl <returned URL>

5.4 Configurations

Configurations are read from config.json.

Example:

{
    "port": 8080,
    "cloud_storage": {
        "bucket_name": "test-bucket-001-a"
    },
    "firestore": {
        "project_id": "my-project-xyz",
        "collection_name": "test_collection_001"
    },
    "postgres": {
        "user": "postgres",
        "password": "password",
        "host": "10.xxx.xx.xxx",
        "port": 5432,
        "database_name": "test",
        "table_name": "test_table"
    }
}

5.5 References

• GoogleCloudPlatform / golang-samples