How can I differentiate between different span types in Jaeger?

Custom Span Types in Jaeger: A Guide for APM Users

Jaeger is a powerful tool for tracing and monitoring the performance of your applications. One essential aspect of tracing is the ability to categorize and differentiate spans based on their type. In this article, we'll explore how you can define and use custom span types in Jaeger.

Understanding Span Types

In Jaeger, "span types" refer to the different categories or classifications of spans. Spans represent individual units of work or operations within a distributed system and are essential for understanding the flow of requests and the performance of your applications.

While Jaeger doesn't have an explicit predefined set of span types like some other tracing systems, it allows you to define and use span types based on your application's specific needs.

Here are some common examples of span types that you might encounter in Jaeger:

HTTP Request: Spans related to incoming HTTP requests and their processing.
Database Query: Spans associated with database queries and their execution.
RPC (Remote Procedure Call): Spans related to remote procedure calls between different services or microservices.
Cache Operation: Spans that involve caching operations, such as cache reads or writes.
Internal Processing: Spans for internal processing or computation within a service.
Messaging: Spans related to messaging systems, such as message queue processing.
External Service: Spans for interactions with external services or APIs.
Error or Exception: Spans that capture error or exception handling within your application.
Custom: You can define custom span types to categorize spans based on your application's specific logic or requirements.

The exact set of span types used in your Jaeger implementation may vary depending on your application architecture and the level of granularity you need for tracing.

Adding Custom Span Types

To differentiate between different span types in Jaeger, you'll need to use instrumentation in your code to add relevant metadata, tags, or annotations to your spans.

In Python, you use the set_tag method to add a custom tag named "span.type" to each span, specifying its type, whether it's an "HTTP Request" or "Database Query."

In Go, you initialize a Jaeger tracer, create spans for an "HTTP Request" and "Database Query," and use the SetTag method to add the custom tag "span.type" to each span.

By adding these custom tags to your spans, you can effectively differentiate span types within Jaeger's UI in Logit.io. This feature makes it easier to filter and analyze spans based on their types, helping with performance analysis and troubleshooting in Jaeger.

Below, we'll include examples in different programming languages (Python and Go) to demonstrate how you can achieve this.

Python Example:

In Python, you can use the OpenTelemetry library to create and customize spans. Here's an example of how to differentiate span types using tags:

import opentracing
 
# Create a span for an HTTP request
 
with opentracing.start_span("HTTP Request") as http_span:
 
    http_span.set_tag("span.type", "HTTP Request")
 
    # Your code for handling the HTTP request here
 
# Create a span for a database query
 
with opentracing.start_span("Database Query") as db_span:
 
    db_span.set_tag("span.type", "Database Query")
 
    # Your code for executing the database query here

Go Example:

In Go, you can use the OpenTelemetry package to instrument your code and differentiate span types. Here's an example:

package main

import (
  "github.com/opentracing/opentracing-go"
  "github.com/opentracing/opentracing-go/ext"
  "github.com/opentracing/opentracing-go/log"
  "jaeger-client-go/config"
  "os"
) 

func main() {
  // Initialize Jaeger tracer

  cfg, _ := config.FromEnv()

  tracer, closer, _ := cfg.NewTracer()

  defer closer.Close()

  opentracing.SetGlobalTracer(tracer)

  // Create a span for an HTTP request

  httpSpan := opentracing.StartSpan("HTTP Request")

  defer httpSpan.Finish()

  ext.SpanKindRPCClient.Set(httpSpan)

  httpSpan.SetTag("span.type", "HTTP Request")

  // Your code for handling the HTTP request here

  // Create a span for a database query

  dbSpan := opentracing.StartSpan("Database Query")

  defer dbSpan.Finish()

  ext.SpanKindRPCClient.Set(dbSpan)

  dbSpan.SetTag("span.type", "Database Query")

  // Your code for executing the database query here
}

By adding these custom tags to your spans, you can later use Jaeger's UI within your APM platform to filter and differentiate spans based on their types. This makes it easier to analyze and troubleshoot performance and tracing data in Jaeger.

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