Google cloud functions context

Google cloud functions context DEFAULT
// Copyright Google LLC//// Licensed under the Apache License, Version (the "License");// you may not use this file except in compliance with the License.// You may obtain a copy of the License at//// http://www.apache.org/licenses/LICENSE//// Unless required by applicable law or agreed to in writing, software// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.// See the License for the specific language governing permissions and// limitations under the License.packagecom.google.cloud.functions;importjava.util.Collections;importjava.util.Map;/** An interface for event function context. */publicinterfaceContext {/** * Returns event ID. * * @return event ID*/StringeventId();/** * Returns event timestamp. * * @return event timestamp*/Stringtimestamp();/** * Returns event type. * * @return event type*/StringeventType();/** * Returns event resource. * * @return event resource*/Stringresource();/** * Returns additional attributes from this event. For CloudEvents, the entries in this map will * include the * <ahref="https://github.com/cloudevents/spec/blob/v/spec.md#required-attributes">required * attributes</a> and may include * <ahref="https://github.com/cloudevents/spec/blob/v/spec.md#required-attributes">optional * attributes</a> and * <ahref="https://github.com/cloudevents/spec/blob/v/spec.md#extension-context-attributes"> * extension attributes</a>. * * <p>The map returned by this method may be empty but is never null.</p> * * @return additional attributes form this event.*/ default Map<String, String>attributes() {returnCollections.emptyMap(); }}
Sours: https://github.com/GoogleCloudPlatform/functions-framework-java/blob/master/functions-framework-api/src/main/java/com/google/cloud/functions/Context.java

Background Functions

This is part of a Google Cloud Functions Tutorial Series. Check out the series for all the articles.

In an earlier part of the series, we covered writing Foreground Functions that were based on HTTP Triggers. In this post, we are going to look at writing background functions that can be supported by events raised by two specific event providers that are supported in Google Cloud Functions: Cloud Pub/Sub and Google Cloud Storage.

This post will not be a tutorial for Cloud Pub/Sub and Google Cloud Storage. Please refer to their respective documentation on the same.

First up, it is important to understand a few points about Background functions:

  • Unlike HTTP Trigger or Foreground functions that you invoke directly, Background functions cannot be invoked directly.
  • They will be invoked as part of event triggers that occur in supported Google Cloud Platform Event Providers.
  • Two Google Cloud Platform Event Providers are supported by Background Functions : Cloud Pub/Sub and Google Cloud Storage. These Event Providers are available in GA and not in Beta. Note that over time, Cloud Functions will support more Event Providers and some of them are already being supported in Beta and/or Alpha like Cloud Firestore, BigQuery and Compute Engine.
  • Cloud Pub/Sub is a global message queue that is part of the Google Cloud Platform. It works on the fundamental messaging concepts like Queues, Topics, Messages, Subscribers and Subscriptions.
  • Google Cloud Storage is a distributed and global blob store. You can upload and store your files, blobs into directories or buckets.
  • A Background Google Cloud Function based on Cloud Pub/Sub will get triggered when a message is published to a Pub/Sub Topic. It other words, our Background Google Cloud Function will have a subscription i.e. it subscribes to messages published on a specific Pub/Sub Topic.
  • A Background Google Cloud Function based on Cloud Storage will get triggered by multiple actions that can happen in Cloud Storage Buckets. For e.g. you can listen to metadata changes, file uploads, file deletes and more. Each of these events can trigger your Background Cloud Function.

Background Cloud Function Parameters

The Background Cloud Functions will be triggered as a result of the message being published to a Pub/Sub Topic or file changes in specific Google Cloud Storage buckets.

You have a choice of using Node.js 6 or Node.js 8 runtimes with Google Cloud Functions. The sections below will indicate the key differences in terms of method signatures and other points. Note that Node.js 8 brings new features to the table like and and so it completely depends which runtime you want to go with. Keep in mind that at the time of writing Node.js 8 is in Beta.

Node.js 6

The function signature of Background Cloud Functions will take 2 parameters:

A skeletal outline for your Background function will look like this:

exports.yourfunction = (event, callback) => { // Extract information from event object

// Your function logic callback(); //Invoke the callback to indicate that your
//function is complete}

The object will contain the following properties, which can be of interest in your function logic. This is taken from the official documentation:

The property will have a specific schema depending on whether the event is from the Cloud Pub/Sub event or from Google Cloud Storage event.

Node.js 8

The function signature of Background Cloud Functions will take 2 parameters:

A skeletal outline for your Background function will look like this:

exports.yourfunction = (data, context, callback) => { // Extract information from event object

// Your function logic callback(); //Invoke the callback to indicate that your
//function is complete}

Compared to the function signature for Node.js 6 where you had to extract both the and from the object, in Node.js 8 function signature, the first parameter is the object, the 2nd parameter is , which is provided as a separate parameter as shown above.

We will cover more on this in the respective sections for two Event Provider triggered functions.

Let us take a look at writing our first Cloud Function based on the Cloud Pub/Sub Event Provider. A skeletal template for the same (taken from the default code that appears) is shown below. We are covering this for Node.js 6 version for now.

Note that the object that we mentioned has the property that will contain the message that was published to the Pub/Sub Topic. This message is encoded in base64 format, so you will need to decode the same in your code. Similarly, take a look at the other attributes that you might be interested in your function logic.

Let us go ahead and write a Google Cloud Function based on Pub/Sub now.

The first step is to be logged into the Cloud Console with your Cloud Project selected. Click on Cloud Functions from the main menu and click on Create Function. This will lead to the Cloud Function creation dialog as shown below:

Let us look at the form parameters:

  • Name : Give it some name. For e.g. pubsubfunction1, etc.
  • Memory : You can select MB or MB, since this is more of a test function.
  • Trigger: Select Cloud Pub/Sub topic this time.
  • In the Topic dropdown, click on new Topic. We are going to use a new topic over here. This will bring up a Topic form as shown below, where you can provide the topic name. Click on CREATE.
  • Runtime : Go with Node.js 6
  • Go with other defaults for Inline Source Editor, function to invoke, etc. We are going to use the standard code template pre-filled with us since our intent is to understand the mechanics of the whole process.
  • Click on Create button to create the function.

On successful function creation, you will be led to the function screen as shown below:

Once you click on the function, this will lead to the Function details screen. Click on the Trigger tab as shown below. Notice the Trigger type and Pub/Sub topic name.

Click on Source tab. This will lead to the source for your Cloud Function as shown below:

index.js

exports.helloPubSub = (event, callback) => {
const pubsubMessage = event.data;
console.log(Buffer.from(pubsubMessage.data, ‘base64’).toString());
callback();
};

The code is straightforward:

  • Notice that our function signature takes two parameters as explained before i.e. and
  • The property will contain the contents of the message published.
  • The message data is in base64 format. So the code decodes it into plain text and uses to log the message. This will be eventually visible in the Stackdriver logs.
  • Finally we indicate that we are done with our function execution by invoking the method.

Let us test our function now. Click on the Testing tab and enter the sample data as shown below. Keep in mind that we are base64 encoding our data to simulate how the message will be published to the Pub/Sub topic.

Click on the Test the function button. This will invoke our Cloud function and you can see that in the logs below.

But keep in mind that we simply used the testing message to simulate a message that was being published to the Pub/Sub topic. How about actually using Pub/Sub in Cloud Console and publish the message to the topic from there. That should then invoke our function because it has a subscription to any message published on that topic. Let’s do that.

Click on Pub/Sub from the Cloud Console main menu. In the list of topics, you should find the topic that we created while creating the Cloud Function. You will also notice that there is already a subscription present for our Topic, which means that the messages that are published to this topic will be sent to the subscribers to that topic. And it is no surprise that the subscription is one of our Cloud Function, which will get invoked when a message is published to that topic.

Click on the ellipsis at the end and it will bring up a list of options as shown below. Select Publish message since we want to publish a message to this topic.

In the Publish message form, enter the message that you want to send and click on Publish button.

This will publish the message to the topic. This in turn should invoke our Cloud Function. Since we are logging the message that is received via the statements in our Cloud Function code, we can visit the Stackdriver Logging and we find that our function did get invoked successfully.

This completes the task of writing our first Cloud Function based on Pub/Sub Event Provider.

Node.js 8

So far we used the Node.js 6 runtime. In case we wanted to use the Node.js 8 runtime, we would do the following:

  1. While creating the function , simply select Node.js 8 runtime.
  2. The index.js code that will be provided as a template is shown below. Note that as we explained earlier the parameters are and , there is no parameter here. Since we are only interested in extracting out the data published, we continue to the use the attribute on the object as shown below:
exports.helloPubSub = (data, context, callback) => {

const pubsubMessage = event.data;
console.log(Buffer.from(pubsubMessage, ‘base64’).toString());
callback();};

Let us take a look at writing our first Cloud Function based on the Cloud Storage Provider. A skeletal template for the same (taken from the default code that appears) is shown below. We are covering this for Node.js 6 version for now.

/**
* Triggered from a change to a Cloud Storage bucket.
*
* @param {!Object} event Event payload and metadata.
* @param {!Function} callback Callback function to signal completion.
*/exports.helloGCS = (event, callback) => {
console.log(`Processing file: ${event.data.name}`);
callback();
};

Note that the object that we mentioned has the property that will contain information on the Google Cloud Storage Event. It contains information on Bucket name, Content-type and other metadata too. Similarly, take a look at the other attributes that you might be interested in your function logic.

Do note that always call the callback() function or return a Promise from your function to indicate that your function processing is complete.

Let us go ahead and write a Google Cloud Function based on Cloud Storage now.

The first step is to be logged into the Cloud Console with your Cloud Project selected. Click on Cloud Functions from the main menu and click on Create Function. This will lead to the Cloud Function creation dialog as shown below:

Let us look at the form parameters:

  • Name : Give it some name. For e.g. gcs-function1, etc.
  • Memory : You can select MB or MB, since this is more of a test function.
  • Trigger: Select Cloud Storage bucket this time.
  • In Bucket field, click on Browse and create a unique Bucket name that we will be monitoring for any file uploads, metadata changes, etc.
  • In the Event Type, select the Finalize/Create event. This event is created when the file has been successfully created and written to the Google Cloud Storage Bucket that we are monitoring.
  • Runtime: Select Node.js 6.
  • In the Source tab, please delete the source code present and replace it with the one shown below for the index.js file.
exports.helloGCSGeneric = (event, callback) => {const file = event.data;
const context = event.context;console.log(` Event ${context.eventId}`);
console.log(` Event Type: ${context.eventType}`);
console.log(` Bucket: ${file.bucket}`);
console.log(` File: ${file.name}`);
console.log(` Metageneration: ${file.metageneration}`);
console.log(` Created: ${file.timeCreated}`);
console.log(` Updated: ${file.updated}`);callback();};

Ensure that the function name that you export is .

  • Click on Create button to create the function.

On successful function creation, you will be led to the function screen as shown below:

Click on the function to view the function details (Trigger tab) as shown below. Note the Trigger type and our Bucket name that we specified.

Let us test the function now via Google Cloud Storage service in the Cloud Console. Navigate to Cloud Storage in the Cloud Console. You should see a screen as shown below:

Click on the specific bucket that we created. This will lead you to a screen as shown below:

Go ahead and click on Upload Files button. Select any file from your local machine and upload it.

Once the file is successfully uploaded, we are tracking for all changes that are happening in the gcs-function-bucket1, so our function should get invoked and we should see the required output in the Stackdriver Logging service as shown below:

This completes our task of writing a Google Cloud Function based on Google Cloud Storage.

Node.js 8

So far we used the Node.js 6 runtime. In case we wanted to use the Node.js 8 runtime, we would do the following:

  1. While creating the function , simply select Node.js 8 runtime.
  2. In the index.js code that is provided for the function, use the following:
exports.helloGCSGeneric = (data, context, callback) => {
const gcsEvent = data;
console.log(`Processing file: ${gcsEvent.name}`); console.log(`Event ${context.eventId}`);
console.log(`Event Type: ${context.eventType}`);
console.log(`Bucket: ${gcsEvent.bucket}`);
console.log(`Metageneration: ${gcsEvent.metageneration}`);
console.log(`Created: ${gcsEvent.timeCreated}`);
console.log(`Updated: ${gcsEvent.updated}`);

};

As a best practice, always remember to invoke the from your function. This will indicate that your function processing is complete and the service can calculate the time that it has taken your function to run. If you do not invoke the callback, your function will be considered as running till it times out, which is not something that you want to do.

There are multiple ways in you can invoke the . They are listed below:

  • A method without parameters or value indicates success. For e.g. you can indicate success like the following style too
  • If you wish to return a failure from your function, which will get logged in Stackdriver logging as an ERROR, you can do so by specifying an object as the first parameter or even a value there. For e.g. or

You don’t have to always specify a to denote function completion. You could return a too or alternately return a discrete value from your function or throw an Error object from your code. Cloud Functions will handle that as a callback for you. In this case, do remember to omit the callback parameter from the function signature.

Here is an example of throwing an Error object from your code or returning a discrete value. Both of these techniques are valid ways to indicate function completion.

exports.somefunction = (event) => { //Your function logic if (some_condition === true) {
return "a value";
} else {
throw new Error('An error message');
}};

A final way of not using the callback is to wrap your function using the keyword (which causes your function to implicitly return a Promise).

This completes our section on writing Background Cloud Functions.

Proceed to the next part : Monitoring Cloud Functions or go back to the Google Cloud Functions Tutorial Home Page.

Sours: https://rominirani.com/google-cloud-functions-tutorial-writing-background-functions-ef27ddde5
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Functions Framework for Python

PyPI version

Python unit CIPython lint CIPython conformace CI

An open source FaaS (Function as a service) framework for writing portable Python functions -- brought to you by the Google Cloud Functions team.

The Functions Framework lets you write lightweight functions that run in many different environments, including:

The framework allows you to go from:

defhello(request): return"Hello world!"

To:

curl http://my-url # Output: Hello world!

All without needing to worry about writing an HTTP server or complicated request handling logic.

Features

  • Spin up a local development server for quick testing
  • Invoke a function in response to a request
  • Automatically unmarshal events conforming to the CloudEvents spec
  • Portable between serverless platforms

Installation

Install the Functions Framework via :

pip install functions-framework

Or, for deployment, add the Functions Framework to your file:

Quickstarts

Quickstart: Hello, World on your local machine

Create an file with the following contents:

defhello(request): return"Hello world!"

Your function is passed a single parameter, , which is a Flask object.

Run the following command:

functions-framework --target=hello

Open http://localhost/ in your browser and see Hello world!.

Quickstart: Set up a new project

Create a file with the following contents:

defhello(request): return"Hello world!"

Now install the Functions Framework:

pip install functions-framework

Use the command to start the built-in local development server:

functions-framework --target hello --debug * Serving Flask app "hello" (lazy loading) * Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Debug mode: on * Running on http:/// (Press CTRL+C to quit)

(You can also use if you potentially have multiple language frameworks installed).

Send requests to this function using from another terminal window:

curl localhost # Output: Hello world!

Quickstart: Error handling

The framework includes an error handler that is similar to the function, which allows you to handle specific error types with a decorator:

[email protected]_framework.errorhandler(ZeroDivisionError)defhandle_zero_division(e): return"I'm a teapot", deffunction(request): 1/0return"Success",

This function will catch the and return a different response instead.

Quickstart: Pub/Sub emulator

  1. Create a file with the following contents:

    defhello(event, context): print("Received", context.event_id)
  2. Start the Functions Framework on port

    functions-framework --target=hello --signature-type=event --debug --port=
  3. In a second terminal, start the Pub/Sub emulator on port

    export PUBSUB_PROJECT_ID=my-project gcloud beta emulators pubsub start \ --project=$PUBSUB_PROJECT_ID \ --host-port=localhost

    You should see the following after the Pub/Sub emulator has started successfully:

  4. In a third terminal, create a Pub/Sub topic and attach a push subscription to the topic, using as its push endpoint. Publish some messages to the topic. Observe your function getting triggered by the Pub/Sub messages.

    export PUBSUB_PROJECT_ID=my-project export TOPIC_ID=my-topic export PUSH_SUBSCRIPTION_ID=my-subscription $(gcloud beta emulators pubsub env-init) git clone https://github.com/googleapis/python-pubsub.git cd python-pubsub/samples/snippets/ pip install -r requirements.txt python publisher.py $PUBSUB_PROJECT_ID create $TOPIC_ID python subscriber.py $PUBSUB_PROJECT_ID create-push $TOPIC_ID$PUSH_SUBSCRIPTION_ID http://localhost python publisher.py $PUBSUB_PROJECT_ID publish $TOPIC_ID

    You should see the following after the commands have run successfully:

    And in the terminal where the Functions Framework is running:

For more details on extracting data from a Pub/Sub event, see https://cloud.google.com/functions/docs/tutorials/pubsub#functions_helloworld_pubsub_tutorial-python

Quickstart: Build a Deployable Container

  1. Install Docker and the tool.

  2. Build a container from your function using the Functions buildpacks:

  3. Start the built container:

  4. Send requests to this function using from another terminal window:

Run your function on serverless platforms

Google Cloud Functions

This Functions Framework is based on the Python Runtime on Google Cloud Functions.

On Cloud Functions, using the Functions Framework is not necessary: you don't need to add it to your file.

After you've written your function, you can simply deploy it from your local machine using the command-line tool. Check out the Cloud Functions quickstart.

Cloud Run/Cloud Run on GKE

Once you've written your function and added the Functions Framework to your file, all that's left is to create a container image. Check out the Cloud Run quickstart for Python to create a container image and deploy it to Cloud Run. You'll write a when you build your container. This allows you to specify exactly what goes into your container (including custom binaries, a specific operating system, and more). Here is an example that calls Functions Framework.

If you want even more control over the environment, you can deploy your container image to Cloud Run on GKE. With Cloud Run on GKE, you can run your function on a GKE cluster, which gives you additional control over the environment (including use of GPU-based instances, longer timeouts and more).

Container environments based on Knative

Cloud Run and Cloud Run on GKE both implement the Knative Serving API. The Functions Framework is designed to be compatible with Knative environments. Just build and deploy your container to a Knative environment.

Configure the Functions Framework

You can configure the Functions Framework using command-line flags or environment variables. If you specify both, the environment variable will be ignored.

Command-line flagEnvironment variableDescription
The host on which the Functions Framework listens for requests. Default:
The port on which the Functions Framework listens for requests. Default:
The name of the exported function to be invoked in response to requests. Default:
The signature used when writing your function. Controls unmarshalling rules and determines which arguments are used to invoke your function. Default: ; accepted values: , or
The path to the file containing your function. Default: (in the current working directory)
A flag that allows to run functions-framework to run in debug mode, including live reloading. Default:
A flag that allows for testing the function build from the configuration without creating a server. Default:

Enable Google Cloud Functions Events

The Functions Framework can unmarshall incoming Google Cloud Functions event payloads to and objects. These will be passed as arguments to your function when it receives a request. Note that your function must use the -style function signature:

defhello(event, context): print(event) print(context)

To enable automatic unmarshalling, set the function signature type to using the command-line flag or the environment variable. By default, the HTTP signature will be used and automatic event unmarshalling will be disabled.

For more details on this signature type, see the Google Cloud Functions documentation on background functions.

See the running example.

Enable CloudEvents

The Functions framework can also unmarshall incoming CloudEvents payloads to the object. This will be passed as a cloudevent to your function when it receives a request. Note that your function must use the -style function signature:

defhello(cloudevent): print(f"Received event with ID: {cloudevent['id']}")

To enable automatic unmarshalling, set the function signature type to using the command-line flag or the environment variable. By default, the HTTP signature type will be used and automatic event unmarshalling will be disabled.

For more details on this signature type, check out the Google Cloud Functions documentation on background functions.

Advanced Examples

More advanced guides can be found in the directory. You can also find examples on using the CloudEvent Python SDK here.

Contributing

Contributions to this library are welcome and encouraged. See CONTRIBUTING for more information on how to get started.

Sours: https://github.com/GoogleCloudPlatform/functions-framework-python

Google Cloud Functions (Serverless)

The extension scans your project for a class that directly implements the Google Cloud , or interface. It must find a class in your project that implements one of these interfaces or it will throw a build time failure. If it finds more than one function classes, a build time exception will also be thrown.

Sometimes, though, you might have a few related functions that share code and creating multiple maven modules is just an overhead you don&#;t want to do. The extension allows you to bundle multiple functions in one project and use configuration or an environment variable to pick the function you want to deploy.

To configure the name of the function, you can use the following configuration property:

The property tells Quarkus which function to deploy. This can be overridden with an environment variable too.

The CDI name of the function class must match the value specified within the property. This must be done using the annotation.

The HttpFunction

  1. The annotation allows to name the CDI bean to be used by the property, this is optional.

  2. The function must be a CDI bean

  3. This is a regular Google Cloud Function implementation, so it needs to implement .

  4. Injection works inside your function.

  5. This is standard Google Cloud Function implementation, nothing fancy here.

The BackgroundFunction

This is triggered by a Storage event, you can use any events supported by Google Cloud instead.

  1. The annotation allows to name the CDI bean to be used by the property, this is optional.

  2. The function must be a CDI bean

  3. This is a regular Google Cloud Function implementation, so it needs to implement .

  4. Injection works inside your function.

  5. This is standard Google Cloud Function implementation, nothing fancy here.

  6. This is the class the event will be deserialized to.

The RawBackgroundFunction

This is triggered by a PubSub event, you can use any events supported by Google Cloud instead.

  1. The annotation allows to name the CDI bean to be used by the property, this is optional.

  2. The function must be a CDI bean

  3. This is a regular Google Cloud Function implementation, so it needs to implement .

  4. Injection works inside your function.

  5. This is standard Google Cloud Function implementation, nothing fancy here.

Sours: https://quarkus.io/guides/gcp-functions

Functions context cloud google

What Are Google Cloud Functions?

Google cloud functions

Google Cloud’s event-driven serverless compute platform. GCF is priced according to how long your function runs, how many times it’s invoked, and how many resources you provision for the function

In support of GCF’s “no lock-in” value prop, the Functions Framework lets you write lightweight functions that run in many different environments, including: Cloud Functions, your local development machine, Cloud Run, and Knative-based environments.

Use open source FaaS (function as a service) framework to run functions across multiple environments and prevent lock-in. Supported environments include Cloud Functions, local development environment, on-premises, Cloud Run, Cloud Run for Anthos, and other Knative-based serverless environments.

Cloud Functions event sources include HTTP for web, mobile, or backend applications, Cloud Storage, Cloud Pub/Sub, Cloud Firestore, Firebase (Realtime Database, Storage, Analytics, Auth), and Stackdriver Logging.

Creating a response to an event is done with a trigger. Binding a function to a trigger allows you to capture and act on events.

GCF supports the following trigger types:  HTTP, Cloud Pub/Sub, and other sources like Firebase.

HTTP events trigger HTTP functions, and all other event types trigger background functions.

HTTP Functions pass the ExpressJS parameters (request, response).

Background Functions pass the parameters (data, context, callback).

Google Cloud Functions Runtimes

Google Cloud Functions supports Node.js, Python, and Go, with Java coming soon.

GCF has two main types of functions: HTTP and Background.

Invoke HTTP functions from standard HTTP requests. These HTTP requests wait for the response and support handling of common HTTP request methods like GET, PUT, POST, DELETE and OPTIONS.

Background functions are invoked directly by events from your Cloud infrastructure, such as messages on a Pub/Sub topic, or changes in a Cloud Storage bucket.

Sours: https://www.triggermesh.com/faq/what-are-google-cloud-functions
Google Cloud Functions - Serverless in GCP

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