import functions_framework
import ddtrace
import logging
from datadog import initialize, statsd
import os

ddtrace.patch(logging=True)
file_path = "/shared-volume/logs/app.log" # This is the path to the shared volume
os.makedirs(os.path.dirname(file_path), exist_ok=True)
FORMAT = ('%(asctime)s %(levelname)s [%(name)s] [%(filename)s:%(lineno)d] '
          '[dd.service=%(dd.service)s dd.env=%(dd.env)s dd.version=%(dd.version)s dd.trace_id=%(dd.trace_id)s dd.span_id=%(dd.span_id)s] '
          '- %(message)s')

logging.basicConfig(level=logging.DEBUG, filename=file_path, format=FORMAT, force=True)
ddlogs = []
initialize(**{'statsd_port': 8125})

@ddtrace.tracer.wrap()
@functions_framework.http
def hello_http(request):
  log = request.args.get("log")
  statsd.increment("ninja.run.func.sent", tags=["runtime:python"])
  if log != None:
    with ddtrace.tracer.trace('sending-test-logs') as span:
      span.set_tag('logs', 'TEST')
      logging.debug(log)
      ddlogs.append(log)
  return "Welcome to Datadog!💜"

Flask
functions-framework
ddtrace
datadog

package gcfv2;

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

import com.timgroup.statsd.NonBlockingStatsDClientBuilder;
import com.timgroup.statsd.StatsDClient;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class HelloworldApplication implements HttpFunction {
  private static final StatsDClient Statsd = new NonBlockingStatsDClientBuilder().hostname("localhost").build();
  protected static final Logger logger4 = LogManager.getLogger();

  public static void createLogFile() {
    File directory = new File("shared-volume/logs");
    if (!directory.exists()) {
      directory.mkdirs(); // Create directory if it doesn't exist
    }
    else {
      try {
        File logFile = new File("shared-volume/logs/app.log");
        if (!logFile.exists()){
          logFile.createNewFile();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

  public void service(final HttpRequest request, final HttpResponse response) throws Exception {
    createLogFile();
    Statsd.incrementCounter("ninja.run.func.sent");
    final BufferedWriter writer = response.getWriter();
    logger4.info("Hello GCP!");
    writer.write("Hello Datadog!!");
  }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>functions</groupId>
  <artifactId>functions-hello-world</artifactId>
  <version>1.0.0-SNAPSHOT</version>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <artifactId>libraries-bom</artifactId>
        <groupId>com.google.cloud</groupId>
        <scope>import</scope>
        <type>pom</type>
        <version>26.32.0</version>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <properties>
    <maven.compiler.target>17</maven.compiler.target>
    <maven.compiler.source>17</maven.compiler.source>
  </properties>

  <dependencies>
    <!-- Required for Function primitives -->
    <dependency>
      <groupId>com.google.cloud.functions</groupId>
      <artifactId>functions-framework-api</artifactId>
      <version>1.1.4</version>
    </dependency>
    <dependency>
      <groupId>com.google.cloud.functions.invoker</groupId>
      <artifactId>java-function-invoker</artifactId>
      <version>1.4.0</version>
    </dependency>
    <dependency>
      <groupId>com.datadoghq</groupId>
      <artifactId>java-dogstatsd-client</artifactId>
      <version>4.4.3</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.19.0</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>2.19.0</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <!--
          Google Cloud Functions Framework Maven plugin

          This plugin allows you to run Cloud Functions Java code
          locally. Use the following terminal command to run a
          given function locally:

          mvn function:run -Drun.functionTarget=your.package.yourFunction
        -->
        <groupId>com.google.cloud.functions</groupId>
        <artifactId>function-maven-plugin</artifactId>
        <version>0.11.0</version>
        <configuration>
          <functionTarget>functions.HelloWorld</functionTarget>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.2.4</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

# Download Datadog Java Agent
FROM maven:3.8.3-openjdk-17 AS build

# Set working directory
WORKDIR /

# Download the required Maven dependency
RUN mvn dependency:get -Dartifact=com.google.cloud.functions.invoker:java-function-invoker:1.4.0 \
    && mvn dependency:copy -Dartifact=com.google.cloud.functions.invoker:java-function-invoker:1.4.0 -DoutputDirectory=/

FROM openjdk:17-jdk

# Set the working directory in the container
WORKDIR /
ADD 'https://dtdg.co/latest-java-tracer' dd-java-agent.jar
COPY --from=build java-function-invoker-1.4.0.jar java-function-invoker.jar

# Copy the JAR file into the container
COPY target/functions-hello-world-1.0.0-SNAPSHOT.jar helloworld.jar
ENV JAVA_OPTS=-javaagent:dd-java-agent.jar

# Expose the port (Cloud Run automatically assigns the actual port via $PORT)
ENV PORT=8080
EXPOSE 8080 8125/udp

ENTRYPOINT ["java","-javaagent:/dd-java-agent.jar", "-jar", "/java-function-invoker.jar","--classpath", "/helloworld.jar","--target", "functions.HelloWorld"]

package helloworld

import (
  "fmt"
  "github.com/sirupsen/logrus"
  dd_logrus "gopkg.in/DataDog/dd-trace-go.v1/contrib/sirupsen/logrus"
  "html/template"
  "net/http"
  "os"
  "path/filepath"

  "github.com/DataDog/datadog-go/v5/statsd"
  "github.com/GoogleCloudPlatform/functions-framework-go/functions"
  "gopkg.in/DataDog/dd-trace-go.v1/ddtrace"
  "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
)

const logDir = "/shared-volume/logs"
var ddlogs []string
var logFile *os.File
var logCounter int

var dogstatsdClient *statsd.Client
const homeTemplate = `
<!DOCTYPE html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Datadog Test</title>
</head>
<body>
    <h1>Welcome to Datadog!💜</h1>
    <form action="" method="get">
        <input type="text" name="log" placeholder="Enter Log">
        <button>Add Log</button>
    </form>
    <h3>Logs Sent to Datadog:</h3>
    <ul>
    {{range .}}
        <li>{{.}}</li>
    {{end}}
    </ul>
</body>
`

func init() {
  logrus.SetFormatter(&logrus.JSONFormatter{})
  logrus.AddHook(&dd_logrus.DDContextLogHook{})
  err := os.MkdirAll(logDir, 0755)
  if err != nil {
    panic(err)
  }
  logFilePath := filepath.Join(logDir, "maincontainer.log")
  logrus.Println("Saving logs in ", logFilePath)
  logFileLocal, err := os.OpenFile(logFilePath, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
  if err != nil {
    panic(err)
  }

  logrus.SetOutput(logFileLocal)
  logFile = logFileLocal

  logrus.Print("Main container started...")
  dogstatsdClient, err = statsd.New("127.0.0.1:8125")
  if err != nil {
    panic(err)
  }

  tracer.Start()
  functions.HTTP("HelloHTTP", helloHTTP)
}

// helloHTTP is an HTTP Cloud Function with a request parameter.
func helloHTTP(w http.ResponseWriter, r *http.Request) {
  span := tracer.StartSpan("maincontainer", tracer.ResourceName("/helloHTTP"))
  logrus.Printf("Yay!! Main container works %v", span)
  err := dogstatsdClient.Incr("ninja.run.func.sent", []string{"runtime:go"}, 1)
  if err != nil {
    logrus.Error("Error incrementing counter:", err)
  }
  defer span.Finish()
  sent_log := r.URL.Query().Get("log")
  if sent_log != "" {
    logCounter++
    writeLogsToFile(fmt.Sprintf("received request %d", logCounter), span.Context())
    writeLogsToFile(sent_log, span.Context())
    ddlogs = append(ddlogs, sent_log)
  }

  tmpl, err := template.New("home").Parse(homeTemplate)
  if err != nil {
    logrus.Error("Error parsing template:", err)
  }
  tmpl.Execute(w, ddlogs)
}

func writeLogsToFile(log_msg string, context ddtrace.SpanContext) {
  span := tracer.StartSpan(
    "writeLogToFile",
    tracer.ResourceName("/writeLogsToFile"),
    tracer.ChildOf(context))
  defer span.Finish()
  _, err := logFile.WriteString(log_msg + "\n")
  if err != nil {
    logrus.Println("Error writing to log file:", err)
  }
}

module example.com/gcf

require (
	github.com/DataDog/datadog-go/v5 v5.5.0
	github.com/GoogleCloudPlatform/functions-framework-go v1.9.0
	github.com/sirupsen/logrus v1.9.3
	gopkg.in/DataDog/dd-trace-go.v1 v1.68.0
)

using Google.Cloud.Functions.Framework;
using StatsdClient;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using System.IO;
using System.Text.Json;
using System.Threading.Tasks;
using Datadog.Trace;
using Serilog;
using Serilog.Formatting.Compact;
using Serilog.Sinks.File;

namespace HelloHttp;

public class Function : IHttpFunction
{
   public DogStatsdService _dsd;

   public Function() {
        var dogstatsdConfig = new StatsdConfig
       {
           StatsdServerName = "127.0.0.1",
           StatsdPort = 8125,
       };

       _dsd = new DogStatsdService();
       _dsd.Configure(dogstatsdConfig);

        string directoryPath = "/shared-volume/logs";
        string filePath = Path.Combine(directoryPath, "app.log");
               // Create the directory if it doesn't exist
        if (!Directory.Exists(directoryPath))
        {
            Directory.CreateDirectory(directoryPath);
        }

        // Create a file if it doesn't exist
        if (!File.Exists(filePath))
        {
            File.WriteAllText(filePath, "Hello, this is the content of the file.");
        }
       Log.Logger = new LoggerConfiguration()
           .WriteTo.File(new RenderedCompactJsonFormatter(), "/shared-volume/logs/app.log")
           .CreateLogger();
   }

   public async Task HandleAsync(HttpContext context)
   {
       using (var scope = Tracer.Instance.StartActive("test-function-dotnet"))
       {
           _dsd.Increment("ninja.run.func.sent", tags: new[] {"runtime:dotnet"});
           Log.Information("Hello Datadog Cloud Run Functions! 💜");
           await context.Response.WriteAsync("Hello Datadog Cloud Run Functions! 💜");
       }
   }
}

<Project Sdk="Microsoft.NET.Sdk">
 <PropertyGroup>
   <OutputType>Exe</OutputType>
   <TargetFramework>net8.0</TargetFramework>
 </PropertyGroup>

 <ItemGroup>
   <PackageReference Include="Google.Cloud.Functions.Hosting" Version="2.0.0" />
   <PackageReference Include="Datadog.Trace.Bundle" Version="2.56.0" />
   <PackageReference Include="StatsdClient" Version="2.0.68" />
   <PackageReference Include="DogStatsD-CSharp-Client" Version="8.0.0" />
    <PackageReference Include="Serilog" Version="4.1.0" />
    <PackageReference Include="Serilog.Formatting.Compact" Version="3.0.0" />
    <PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
 </ItemGroup>
</Project>