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 NET6 Web 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 NET6 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 NET6 Web 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 NET6 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="1.2.0-rc1" />
<PackageReference Include="OpenTelemetry.Exporter.Jaeger" Version="1.2.0-rc1" />
<PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.0.0-rc8" />
<PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.0.0-rc8" />
<PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.0.0-rc8" />
<PackageReference Include="OpenTelemetry.Instrumentation.SqlClient" Version="1.0.0-rc8" />
<PackageReference Include="OpenTelemetry.Instrumentation.StackExchangeRedis" Version="1.0.0-rc8" />External Dependencies
- Jaeger
- MSSQL Server
- RabbitMq
- Redis Cache
How to run the apps
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.
If you don't want to use the compose file you can use docker to start the dependencies manually, you can ran the following commands:
- docker run -d --name jaeger -e COLLECTOR_ZIPKIN_HTTP_PORT=19411 -p 5775:5775/udp -p 6831:6831/udp -p 6832:6832/udp -p 5778:5778 -p 16686:16686 -p 14268:14268 -p 19411:19411 jaegertracing/all-in-one
- docker run -d --hostname my-rabbit --name some-rabbit -p 8082:15672 -p 5672:5672 rabbitmq:3.6.15-management
- 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
- docker run -d --name some-redis -p "6379:6379" redis:6.2.1
Output
If you open jaeger you are going to see something like this
