Introduction

This repository contains an example about how to use opentelemetry for tracing when we have a bunch of distributed applications

Content

The repository contains the following applications:

• App1.WebApi is a NET 8 API with 2 endpoints.

  • The /http endpoint makes an HTTP request to the App2 "/dummy" endpoint.
  • The /publish-message endpoint queues a message into a Rabbit queue named "sample".

• App2.RabbitConsumer.Console is a NET 8 console application.

  • Dequeues messages from the Rabbit "sample" queue and makes a HTTP request to the App3 "/sql-to-event" endpoint with the content of the message.

• App3.WebApi is a NET 8 Minimal API with 2 endpoints

  • The /dummy endpoint returns a fixed "Ok" response.
  • The /sql-to-event endpoint receives a message via HTTP POST, stores it in a MSSQL Server and afterwards publishes the message as an event into a RabbitMq queue named "sample_2".

• App4.RabbitConsumer.HostedService is a NET 8 Worker Service.

  • A Hosted Service reads the messages from the Rabbitmq "sample_2" queue and stores it into a Redis cache database.

OpenTelemetry .NET Client

The apps are using the following package versions:

  <PackageReference Include="OpenTelemetry" Version="1.8.0" />
  <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.8.1" />
  <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.8.0" />
  <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.8.0" />
  <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.8.1" />
  <PackageReference Include="OpenTelemetry.Instrumentation.SqlClient" Version="1.8.0-beta.1" />
  <PackageReference Include="ZiggyCreatures.FusionCache.OpenTelemetry" Version="1.0.0" />

External Dependencies

• Jaeger
• MSSQL Server
• RabbitMq
• Redis Cache

How to run the apps

Using docker-compose

The repository contains a docker-compose file that starts up the 4 apps and also the external dependencies.
There is a little caveat in the docker-compose:

• You can control the order of service startup and shutdown with the depends_on option. However, for startup Compose does not wait until a container is “ready” only until it’s running.
  That's a problem because both App3 and App4 need to wait for the rabbitMq container to be ready. To avoid this problem the docker-compose is overwriting the "entrypoint" for both apps and executing a shell script that makes both apps sleep 30 seconds before starting up.

Without using the docker-compose

If you don't want to use the docker-compose file, you can use docker to start the dependencies one by one.

• Run a Jaeger image:

docker run -d --name jaeger \
  -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
  -e COLLECTOR_OTLP_ENABLED=true \
  -p 6831:6831/udp \
  -p 6832:6832/udp \
  -p 5778:5778 \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  -p 14250:14250 \
  -p 14268:14268 \
  -p 14269:14269 \
  -p 9411:9411 \
  jaegertracing/all-in-one:latest

• Run a Rabbitmq image:

docker run -d --name some-rabbit \
  -p 15672:15672 \
  -p 5672:5672 \
  rabbitmq:3.13.1-management

• Run a MSSQL Server

docker run -e "ACCEPT_EULA=Y" \
  -e "SA_PASSWORD=Pass@Word1" \
  -p 1433:1433 \
  -d mcr.microsoft.com/mssql/server:2019-GA-ubuntu-16.04

• Run a Redis immage:

docker run -d --name some-redis \
  -p "6379:6379" \
  redis:7.2.4

Output

If you open Jaeger, you are going to see something like this

Changelog

04/15/2024

• Updated apps to .NET 8.
• Updated OpenTelemetry packages to the latest available version. This update also addresses several known security vulnerabilities.
• Updated System.Data.SqlClient to the latest available version to mitigate known security vulnerabilities.
• From this point forward, App 1 will function as a .NET 8 API that utilizes Controllers, while App 3 will operate as a minimal API without controllers.
• Deleted Startup.cs from both App 1 and App 3.
• App 1 and App 3 now employ the newer WebApplication.CreateBuilder method for application construction, replacing the previous WebHost.CreateDefaultBuilder method.
• App 4 now utilizes the newer Host.CreateApplicationBuilder method to construct a Host, replacing the previous Host.CreateDefaultBuilder method.
• Implemented the C# 12 primary constructor feature across all apps.
• Updated Dockerfile base image from Bullseye distro (Debian 11) to Bookworm distro (Debian 12).
• App 4 now employs the FusionCache library with a Redis Backplane, replacing the use of IDistributedCache.
• Updated the docker-compose file to utilize the latest image versions of RabbitMQ, Redis, and Jaeger.

09/24/2023

• Updated apps to .NET 7.
• Updated OpenTelemetry packages to the latest version.
• Fix breaking changes on the apps due to the OpenTelemetry packages upgrade.
• Removed the OpenTelemetry.Exporter.Jaeger NuGet package from the apps because it has been deprecated. It has been replaced by the OpenTelemetry.Exporter.OpenTelemetryProtocol package.
• Updated the RabbitMQ.Client NuGet package to the latest version.
• Updated the docker-compose file to use the newest image versions of rabbitmq, redis and jaeger. Also the jaeger image is configured so can it can receive OpenTelemetry trace data via the OpenTelemetry Protocol.