Cloud Functions cambió de nombre a Cloud Run Functions. Para obtener más información, consulta la entrada de blog sobre Cloud Run Functions.

Se usó la API de Cloud Translation para traducir esta página.

Diferencias entre el permiso global y el de función

Crea un objeto pesado solo una vez por instancia de la función y lo comparte en todas las invocaciones de la función que alcanzan la instancia determinada.

Explora más

Para obtener documentación en la que se incluye esta muestra de código, consulta lo siguiente:

Muestra de código

C#

Para autenticarte en funciones de Cloud Run, configura las credenciales predeterminadas de la aplicación. Si deseas obtener más información, consulta Configura la autenticación para un entorno de desarrollo local.

using Google.Cloud.Functions.Framework;
using Microsoft.AspNetCore.Http;
using System.Linq;
using System.Threading.Tasks;

namespace Scopes;

public class Function : IHttpFunction
{
    // Global (server-wide) scope.
    // This computation runs at server cold-start.
    // Warning: Class variables used in functions code must be thread-safe.
    private static readonly int GlobalVariable = HeavyComputation();

    // Note that one instance of this class (Function) is created per invocation,
    // so calling HeavyComputation in the constructor would not have the same
    // benefit.

    public async Task HandleAsync(HttpContext context)
    {
        // Per-function-invocation scope.
        // This computation runs every time this function is called.
        int functionVariable = LightComputation();

        await context.Response.WriteAsync(
            $"Global: {GlobalVariable}; function: {functionVariable}",
            context.RequestAborted);
    }

    private static int LightComputation()
    {
        int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
        return numbers.Sum();
    }

    private static int HeavyComputation()
    {
        int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
        return numbers.Aggregate((current, next) => current * next);
    }
}

Go


// h is in the global (instance-wide) scope.
var h string

// init runs during package initialization. So, this will only run during an
// an instance's cold start.
func init() {
	h = heavyComputation()
	functions.HTTP("ScopeDemo", ScopeDemo)
}

// ScopeDemo is an example of using globally and locally
// scoped variables in a function.
func ScopeDemo(w http.ResponseWriter, r *http.Request) {
	l := lightComputation()
	fmt.Fprintf(w, "Global: %q, Local: %q", h, l)
}

Java


import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;

public class Scopes implements HttpFunction {
  // Global (instance-wide) scope
  // This computation runs at instance cold-start.
  // Warning: Class variables used in functions code must be thread-safe.
  private static final int INSTANCE_VAR = heavyComputation();

  @Override
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    // Per-function scope
    // This computation runs every time this function is called
    int functionVar = lightComputation();

    var writer = new PrintWriter(response.getWriter());
    writer.printf("Instance: %s; function: %s", INSTANCE_VAR, functionVar);
  }

  private static int lightComputation() {
    int[] numbers = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    return Arrays.stream(numbers).sum();
  }

  private static int heavyComputation() {
    int[] numbers = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    return Arrays.stream(numbers).reduce((t, x) -> t * x).getAsInt();
  }
}

Node.js

const functions = require('@google-cloud/functions-framework');

// TODO(developer): Define your own computations
const {lightComputation, heavyComputation} = require('./computations');

// Global (instance-wide) scope
// This computation runs once (at instance cold-start)
const instanceVar = heavyComputation();

/**
 * HTTP function that declares a variable.
 *
 * @param {Object} req request context.
 * @param {Object} res response context.
 */
functions.http('scopeDemo', (req, res) => {
  // Per-function scope
  // This computation runs every time this function is called
  const functionVar = lightComputation();

  res.send(`Per instance: ${instanceVar}, per function: ${functionVar}`);
});

PHP


use Psr\Http\Message\ServerRequestInterface;

function scopeDemo(ServerRequestInterface $request): string
{
    // Heavy computations should be cached between invocations.
    // The PHP runtime does NOT preserve variables between invocations, so we
    // must write their values to a file or otherwise cache them.
    // (All writable directories in Cloud Functions are in-memory, so
    // file-based caching operations are typically fast.)
    // You can also use PSR-6 caching libraries for this task:
    // https://packagist.org/providers/psr/cache-implementation
    $cachePath = sys_get_temp_dir() . '/cached_value.txt';

    $response = '';
    if (file_exists($cachePath)) {
        // Read cached value from file, using file locking to prevent race
        // conditions between function executions.
        $response .= 'Reading cached value.' . PHP_EOL;
        $fh = fopen($cachePath, 'r');
        flock($fh, LOCK_EX);
        $instanceVar = stream_get_contents($fh);
        flock($fh, LOCK_UN);
    } else {
        // Compute cached value + write to file, using file locking to prevent
        // race conditions between function executions.
        $response .= 'Cache empty, computing value.' . PHP_EOL;
        $instanceVar = _heavyComputation();
        file_put_contents($cachePath, $instanceVar, LOCK_EX);
    }

    // Lighter computations can re-run on each function invocation.
    $functionVar = _lightComputation();

    $response .= 'Per instance: ' . $instanceVar . PHP_EOL;
    $response .= 'Per function: ' . $functionVar . PHP_EOL;

    return $response;
}

Python

import time

import functions_framework


# Placeholder
def heavy_computation():
    return time.time()


# Placeholder
def light_computation():
    return time.time()


# Global (instance-wide) scope
# This computation runs at instance cold-start
instance_var = heavy_computation()


@functions_framework.http
def scope_demo(request):
    """
    HTTP Cloud Function that declares a variable.
    Args:
        request (flask.Request): The request object.
        <http://flask.pocoo.org/docs/1.0/api/#flask.Request>
    Returns:
        The response text, or any set of values that can be turned into a
        Response object using `make_response`
        <http://flask.pocoo.org/docs/1.0/api/#flask.Flask.make_response>.
    """

    # Per-function scope
    # This computation runs every time this function is called
    function_var = light_computation()
    return f"Instance: {instance_var}; function: {function_var}"

Ruby

# Global (instance-wide) scope.
# This block runs on cold start, before any function is invoked.
#
# Note: It is usually best to run global initialization in an on_startup block
# instead at the top level of the Ruby file. This is because top-level code
# could be executed to verify the function during deployment, whereas an
# on_startup block is run only when an actual function instance is starting up.
FunctionsFramework.on_startup do
  instance_data = perform_heavy_computation

  # To pass data into function invocations, the best practice is to set a
  # key-value pair using the Ruby Function Framework's built-in "set_global"
  # method. Functions can call the "global" method to retrieve the data by key.
  # (You can also use Ruby global variables or "toplevel" local variables, but
  # they can make it difficult to isolate global data for testing.)
  set_global :my_instance_data, instance_data
end

FunctionsFramework.http "tips_scopes" do |_request|
  # Per-function scope.
  # This method is called every time this function is called.
  invocation_data = perform_light_computation

  # Retrieve the data computed by the on_startup block.
  instance_data = global :my_instance_data

  "instance: #{instance_data}; function: #{invocation_data}"
end

¿Qué sigue?

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