Observe tracing using Jaeger

The sample shop service will be used in this guide. Follow the steps given below to observe tracing for BI application in Jaeger.

Step 1 - Set up Jaeger

You can configure BI project to support distributed tracing with Jaeger. This section focuses on configuring Jaeger with Docker as a quick installation.

Tip

There are many possible ways to deploy Jaeger. For more information, see Jaeger Deployment. The easiest option is to use executable binaries listed in Downloads.

Install Jaeger via Docker and start the Docker container by executing the command below.

$ docker run -d -p 13133:13133 -p 16686:16686 -p 4317:4317 jaegertracing/opentelemetry-all-in-one

Step 2 - Import Ballerina Jaeger extension

Create the sample shop service. To include the Jaeger extension into the executable, the ballerinax/jaeger module needs to be imported into your Ballerina project main.bal file.

import ballerinax/jaeger as _;

Jaeger extension has an Opentelemetry GRPC Span Exporter which will push tracing data as batches to the Jaeger server endpoint (default - http://localhost:4317) in opentelemetry format.

Step 3 - Enable observability for the project

Observability can be enabled in a BI project by adding the following section to the Ballerina.toml file by navigating to the file explorer view.

[build-options]
observabilityIncluded=true

Step 4 - Configure Ballerina runtime configurations

Tracing can be enabled in your BI project using configurations similar to the following. Navigate to file explorer and add the following to the Config.toml file.

[ballerina.observe]
tracingEnabled=true
tracingProvider="jaeger"

[ballerinax.jaeger]
agentHostname="localhost"
agentPort=4317
samplerType="const"
samplerParam=1.0
reporterFlushInterval=2000
reporterBufferSize=1000

The table below provides the descriptions of each configuration option and possible values that can be assigned.

Configuration key	Description	Default value	Possible values
ballerinax.jaeger. agentHostname	Hostname of the Jaeger agent	localhost	IP or hostname of the Jaeger agent. If it is running on the same node as BI, it can be localhost.
ballerinax.jaeger. agentPort	Port of the Jaeger agent	4317	The port on which the Jaeger agent is listening.
ballerinax.jaeger. samplerType	Type of the sampling methods used in the Jaeger tracer.	const	const, probabilistic, or ratelimiting.
ballerinax.jaeger. samplerParam	It is a floating value. Based on the sampler type, the effect of the sampler param varies	1.0	For const 0 (no sampling) or 1 (sample all spans), for probabilistic 0.0 to 1.0, for ratelimiting any positive integer (rate per second).
ballerinax.jaeger. reporterFlushInterval	The Jaeger client will be sending the spans to the agent at this interval.	2000	Any positive integer value.
ballerinax.jaeger. reporterBufferSize	Queue size of the Jaeger client.	1000	Any positive integer value.

Step 5 - Run the BI service

When observability is enabled, the BI runtime collects tracing data and traces will be published to Jaeger.

Run the BI service and you will see an output as follows.

Compiling source

Running executable

ballerina: started publishing traces to Jaeger on localhost:4317

Step 6 - Send requests

Send requests to http://localhost:8090/shop/products.

Example cURL commands:

$ curl -X GET http://localhost:8090/shop/products

$ curl -X POST http://localhost:8090/shop/product \
-H "Content-Type: application/json" \
-d '{
    "id": 4, 
    "name": "Laptop Charger", 
    "price": 50.00
}'

$ curl -X POST http://localhost:8090/shop/order \
-H "Content-Type: application/json" \
-d '{
    "productId": 1, 
    "quantity": 1
}'

$ curl -X GET http://localhost:8090/shop/order/0

Step 7 - View distributed tracing on the Jaeger server

Go to http://localhost:16686 and load the web UI of Jaeger to make sure it is functioning properly. You can select the service for which you need tracing information find traces.

The image below is the sample tracing information you can see in Jaeger.