OpenTracing was a set of vendor-neutral APIs and instrumentation standards for distributed tracing, aimed at providing insights into the flow of requests across complex, microservices-based systems. Though now an archived project, its legacy lives on as a foundational element in the development of the more comprehensive OpenTelemetry project.

• **Distributed Tracing:** OpenTracing enabled the creation and propagation of traces, which represent the end-to-end journey of a request as it traverses various services within a distributed system. This helps visualize complex interactions and pinpoint performance bottlenecks or errors.
• **Vendor Neutrality:** OpenTracing's primary goal was to be vendor-neutral, offering a consistent API and instrumentation model across different programming languages and tracing backends. This allowed developers to switch between tracing systems without significant code changes.
• **Spans and Traces:** The core concepts in OpenTracing are spans and traces:

     * **Span:** Represents a single unit of work within a trace, such as a database query or an HTTP request. Spans can be nested to represent hierarchical relationships between operations.
     * **Trace:** A collection of spans that captures the entire path of a request through a distributed system.

• **Context Propagation:** OpenTracing defined mechanisms for propagating trace context across process boundaries, ensuring that spans from different services can be correlated and assembled into a complete trace.
• **Tags and Logs:** Spans can be enriched with tags (key-value pairs) and logs (structured messages) to provide additional context and information about the operation being traced.

• **Vendor Neutrality:** OpenTracing allowed developers to choose from various tracing backends without being tied to a specific vendor.
• **Standardized Instrumentation:** It provided a common set of APIs and conventions for instrumenting applications, making it easier to add tracing capabilities.
• **Improved Observability:** Distributed tracing enabled deeper insights into the behavior and performance of microservices architectures, facilitating troubleshooting and optimization.

1. **Creating a Span (Java):**

```java import io.opentracing.Span; import io.opentracing.Tracer;

Tracer tracer = …; // Obtain a Tracer instance

Span span = tracer.buildSpan(“my-operation”).start(); try {

   // Your application logic here...

   span.finish();

2. **Adding Tags and Logs (Python):**

```python import opentracing

tracer = …

1. Obtain a Tracer instance

span = tracer.start_span(“my-operation”) span.set_tag(“user_id”, 12345) span.log_kv({“event”: “database_query”, “query”: “SELECT * FROM users”}) span.finish() ```

3. **Context Propagation (HTTP Headers):**

```java import io.opentracing.propagation.Format; import io.opentracing.propagation.TextMapInjectAdapter;

Tracer tracer = …; Span span = …;

HttpHeaders headers = new HttpHeaders(); tracer.inject(span.context(), Format.Builtin.HTTP_HEADERS, new TextMapInjectAdapter(headers));

// Send the HTTP request with the injected headers ```

These examples demonstrate basic OpenTracing concepts, but the actual implementations might vary depending on the specific language and tracing backend used.

OpenTracing has been archived and is no longer actively developed. Its concepts and APIs have been merged into OpenTelemetry, a more comprehensive observability framework that includes metrics and logs in addition to traces. If you're starting a new project or considering adding distributed tracing to your application, it's recommended to use OpenTelemetry instead of OpenTracing.

• **OpenTracing (Archived):** s://opentracing.io/(https://opentracing.io/)
• **OpenTelemetry:** s://opentelemetry.io/(https://opentelemetry.io/)