Function deployment and testing in GCP - Commands & Configuration

Introduction

Deploying a function means putting your code into the cloud so it can run when needed. Testing the function ensures it works correctly after deployment.

When you want to run small pieces of code in response to events without managing servers

When you need to quickly update your code and see the changes live

When you want to test if your cloud function responds correctly to HTTP requests

When you want to automate tasks triggered by cloud storage or messaging events

When you want to save costs by running code only when it is needed

Config File - main.py

main.py

def hello_world(request):
    return 'Hello, World!'

This is a simple Python function named hello_world that returns a greeting message. It accepts a request object because it will be triggered by HTTP requests.

Commands

This command deploys the function named 'hello_world' using Python 3.9 runtime. It sets the function to trigger on HTTP requests and allows anyone to call it. The region is set to us-central1.

Terminal

gcloud functions deploy hello_world --runtime python39 --trigger-http --allow-unauthenticated --region us-central1

Expected Output

Deploying function (may take a while)...

Deploying function (may take a while)...done.

availableMemoryMb: 256

entryPoint: hello_world

httpsTrigger:

  url: https://us-central1-your-project.cloudfunctions.net/hello_world

ingressSettings: ALLOW_ALL

labels:

  deployment-tool: cli-gcloud

name: projects/your-project/locations/us-central1/functions/hello_world

runtime: python39

serviceAccountEmail: [e-mail]

sourceUploadUrl: https://storage.googleapis.com/gcf-upload-us-central1/...

status: ACTIVE

timeout: 60s

updateTime: '2024-06-01T12:00:00Z'

versionId: '1'

→

--runtime - Specifies the language runtime version

→

--trigger-http - Sets the function to be triggered by HTTP requests

→

--allow-unauthenticated - Allows public access to the function

This command calls the deployed function 'hello_world' to test if it responds correctly.

Terminal

gcloud functions call hello_world --region us-central1

Expected Output

executionId: abcdef123456

result: Hello, World!

→

--region - Specifies the region where the function is deployed

This command sends an HTTP GET request to the function's URL to test it from outside the cloud console.

Terminal

curl https://us-central1-your-project.cloudfunctions.net/hello_world

Expected Output

Hello, World!

Key Concept

If you remember nothing else from this pattern, remember: deploy your function with the right trigger and test it immediately to confirm it works.

Common Mistakes

Forgetting to add --allow-unauthenticated flag when deploying HTTP functions

The function will reject public requests and appear unreachable

Always include --allow-unauthenticated if you want public access or configure IAM permissions properly

Calling the function without specifying the correct region

The call will fail because the CLI looks in the wrong location

Use --region flag matching the deployment region when calling the function

Not testing the function after deployment

You might miss errors or misconfigurations that prevent the function from working

Always run a test call or HTTP request to verify the function works as expected

Summary

Deploy the function with gcloud specifying runtime, trigger, and access flags.

Test the function using gcloud call command to check the response.

Use curl to send HTTP requests and verify the function works from outside the cloud console.

Practice

1. What does deploying a Cloud Function in GCP mean?

easy

A. Uploading your code to the cloud so it can run when needed

B. Writing code on your local computer only

C. Deleting old versions of your code

D. Running your code only on your personal device

Solution

1. Step 1: Understand deployment meaning

   Deployment means putting your code on the cloud so it can be accessed and run remotely.

2. Step 2: Compare options

   Only Uploading your code to the cloud so it can run when needed describes uploading code to the cloud to run on demand, which matches deployment.

3. Final Answer:

   Uploading your code to the cloud so it can run when needed -> Option A

4. Quick Check:

   Deploy = Upload code to cloud [OK]

Hint: Deployment means putting code on cloud to run [OK]

Common Mistakes:

• Confusing deployment with local coding
• Thinking deployment deletes code
• Assuming deployment runs code only locally

2. Which command correctly deploys a Cloud Function named helloWorld with runtime python39 and trigger HTTP?

easy

A. gcloud functions run helloWorld --runtime python39 --trigger-http

B. gcloud deploy function helloWorld --runtime python39 --trigger-http

C. gcloud functions create helloWorld --runtime python39 --trigger-http

D. gcloud functions deploy helloWorld --runtime python39 --trigger-http

Solution

1. Step 1: Recall correct deploy syntax

   The correct command starts with 'gcloud functions deploy' followed by the function name and flags.

2. Step 2: Check options

   Only gcloud functions deploy helloWorld --runtime python39 --trigger-http uses 'gcloud functions deploy' with correct flags for runtime and trigger.

3. Final Answer:

   gcloud functions deploy helloWorld --runtime python39 --trigger-http -> Option D

4. Quick Check:

   Deploy command = 'gcloud functions deploy' [OK]

Hint: Deploy uses 'gcloud functions deploy' command [OK]

Common Mistakes:

• Using 'create' instead of 'deploy'
• Using 'run' instead of 'deploy'
• Wrong command order or missing flags

3. Given this deployment command:

gcloud functions deploy greetUser --runtime nodejs18 --trigger-http --allow-unauthenticated

What is the effect of the --allow-unauthenticated flag?

medium

A. Only authenticated users can call the function

B. Anyone can call the function without signing in

C. The function will not be deployed

D. The function will require a password to run

Solution

1. Step 1: Understand the flag meaning

   The flag '--allow-unauthenticated' means the function can be called by anyone without login.

2. Step 2: Match options

   Anyone can call the function without signing in correctly states that anyone can call the function without signing in.

3. Final Answer:

   Anyone can call the function without signing in -> Option B

4. Quick Check:

   Allow unauthenticated = open access [OK]

Hint: Allow unauthenticated means open access [OK]

Common Mistakes:

• Thinking it restricts access
• Confusing with authentication required
• Assuming it blocks deployment

4. You deployed a function but get an error when testing it. Which of these is a common cause?

medium

A. The function name in the deploy command does not match the code's exported function

B. You used the correct runtime but forgot to deploy

C. The function was deployed with the correct trigger and runs fine

D. You tested the function before writing any code

Solution

1. Step 1: Identify common deployment error

   If the deployed function name does not match the exported function in code, it causes errors on test.

2. Step 2: Evaluate options

   The function name in the deploy command does not match the code's exported function correctly points out this mismatch as a common cause of errors.

3. Final Answer:

   The function name in the deploy command does not match the code's exported function -> Option A

4. Quick Check:

   Name mismatch causes test errors [OK]

Hint: Match deploy name with exported function name [OK]

Common Mistakes:

• Ignoring function name mismatch
• Assuming deployment without code causes errors
• Testing before code exists

5. You want to deploy a function that triggers on new files in a Cloud Storage bucket named my-bucket. Which command correctly sets this trigger?

hard

A. gcloud functions deploy processFile --runtime python39 --trigger-http

B. gcloud functions deploy processFile --runtime python39 --trigger-topic my-bucket

C. gcloud functions deploy processFile --runtime python39 --trigger-resource my-bucket --trigger-event google.storage.object.finalize

D. gcloud functions deploy processFile --runtime python39 --trigger-bucket my-bucket

Solution

1. Step 1: Identify correct trigger for Cloud Storage

   Cloud Storage triggers use '--trigger-resource' with bucket name and '--trigger-event' with event type like 'google.storage.object.finalize'.

2. Step 2: Check options

   gcloud functions deploy processFile --runtime python39 --trigger-resource my-bucket --trigger-event google.storage.object.finalize correctly uses '--trigger-resource my-bucket' and '--trigger-event google.storage.object.finalize'. Others use wrong triggers.

3. Final Answer:

   gcloud functions deploy processFile --runtime python39 --trigger-resource my-bucket --trigger-event google.storage.object.finalize -> Option C

4. Quick Check:

   Storage trigger = resource + event flags [OK]

Hint: Use --trigger-resource and --trigger-event for storage triggers [OK]

Common Mistakes:

• Using --trigger-http for storage events
• Using --trigger-topic instead of resource/event
• Using non-existent --trigger-bucket flag