Environment variables

Demonstrates how to use environment variables within a Cloud Function.

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Code sample


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

namespace EnvironmentVariables
    public class Function : IHttpFunction
        public async Task HandleAsync(HttpContext context)
            string foo = Environment.GetEnvironmentVariable("FOO")
                ?? "Specified environment variable is not set.";
            await context.Response.WriteAsync(foo);


#include <google/cloud/functions/http_request.h>
#include <google/cloud/functions/http_response.h>
#include <cstdlib>

namespace gcf = ::google::cloud::functions;

gcf::HttpResponse env_vars(gcf::HttpRequest /*request*/) {  // NOLINT
  char const* value = std::getenv("FOO");
  if (value == nullptr) value = "FOO environment variable is not set";
  return gcf::HttpResponse{}.set_payload(value);


// Package tips contains tips for writing Cloud Functions in Go.
package tips

import (

// EnvVar is an example of getting an environment variable in a Go function.
func EnvVar(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "FOO: %q", os.Getenv("FOO"))


import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import java.io.BufferedWriter;
import java.io.IOException;

public class EnvVars implements HttpFunction {

  // Returns the environment variable "foo" set during function deployment.
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    BufferedWriter writer = response.getWriter();
    String foo = System.getenv("FOO");
    if (foo == null) {
      foo = "Specified environment variable is not set.";


exports.envVar = (req, res) => {
  // Sends 'bar' as response


use Psr\Http\Message\ServerRequestInterface;

function envVar(ServerRequestInterface $request): string
    return getenv('FOO') . PHP_EOL;


import os

def env_vars(request):
    return os.environ.get('FOO', 'Specified environment variable is not set.')


require "functions_framework"

FunctionsFramework.http "env_vars" do |_request|
  ENV["FOO"] || "Specified environment variable is not set."

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