Tracing docs (#331)

---------

Co-authored-by: mehrotra234 <[email protected]>

Author: Umang01-hash

docs/Dockerfile

@@ -5,6 +5,7 @@ WORKDIR /app
 COPY  docs/quick-start /app/src/app/docs/quick-start
 COPY  docs/public /app/public
 COPY  docs/advanced-guide /app/src/app/docs/advanced-guide
+COPY  docs/references /app/src/app/docs/references
 COPY  docs/page.md /app/src/app/docs
 COPY  docs/navigation.js /app/src/lib
 

docs/advanced-guide/custom-spans-in-tracing/page.md

@@ -0,0 +1,37 @@
+# Custom Spans In Tracing
+
+GoFr's built-in tracing provides valuable insights into your application's behavior. However, sometimes you might need 
+even more granular details about specific operations within your application. This is where `custom spans` come in.
+
+## How it helps?
+By adding custom spans in traces to your requests, you can:
+
+- **Gain granular insights:** Custom spans allow you to track specific operations or functions within your application, 
+     providing detailed performance data.
+- **Identify bottlenecks:** By analyzing custom spans, you can pinpoint areas of your code that may be causing 
+      performance bottlenecks or inefficiencies.
+- **Improve debugging:** Custom spans enhance your ability to debug issues by providing visibility into the execution 
+      flow of your application.
+
+## Adding Custom Spans:
+
+To add a custom trace to a request, you can use the `Trace()` method of GoFr context, which takes the name of the span as an argument 
+and returns a trace.Span. 
+
+### Usage
+
+```go
+func MyHandler(c context.Context) error {
+    span := c.Trace("my-custom-span")
+    defer span.Close()
+    
+    // Do some work here
+    return nil
+}
+```
+
+In this example, **my-custom-span** is the name of the custom span that you want to add to the request.
+The defer statement ensures that the span is closed even if an error occurs to ensure that the trace is properly recorded.
+
+
+

docs/navigation.js

@@ -20,6 +20,7 @@ export const navigation = [
             { title: 'Monitoring Service Health', href: '/docs/advanced-guide/monitoring-service-health' },
             // { title: 'Supporting OAuth', href: '/docs/advanced-guide/oauth' },
             { title: 'Circuit Breaker Support', href: '/docs/advanced-guide/circuit-breaker' },
+            { title: 'Custom Spans in Tracning', href: '/docs/advanced-guide/custom-spans-in-tracing' },
             // { title: 'Writing gRPC Server', href: '/docs/advanced-guide/grpc' },
             // { title: 'Creating a Static File Server', href: '/docs/advanced-guide/static-file-server' },
             // { title: 'WebSockets', href: '/docs/advanced-guide/websockets' },

docs/quick-start/observability/page.md

@@ -81,21 +81,32 @@ Now that you have created your server, lets see how GoFr by default manages obse
 
   GoFr also provides supports to create requirement specific metrics using [custom metrics](/docs/advanced-guide/publishing-custom-metrics).
 
-
 ## Tracing
+Tracing is a powerful tool for gaining insights into your application's behaviour, identifying bottlenecks, and improving
+system performance. A trace is a tree of spans. It is a collective of observable signals showing the path of work
+through a system. A trace on its own is distinguishable by a `TraceID`.
 
-  GoFr adds traces by default for all the request and response,which allows you to export it to zipkin by adding the configs.
-  It allows to monitor the request going through different parts of application like database, handler etc.
+In complex distributed systems, understanding how requests flow through the system is crucial for troubleshooting performance
+issues and identifying bottlenecks. Traditional logging approaches often fall short, providing limited visibility into
+the intricate interactions between components.
 
-  To see the traces install zipkin image using the following docker command
 
-  ### Setup
+To know more about Tracing click [here](https://opentelemetry.io/docs/concepts/signals/#traces).
 
-  ```bash
-  docker run --name gofr-zipkin -p 2005:9411 -d openzipkin/zipkin:latest
-  ```
 
-  ### Configuration & Usage
+### Automated Tracing in GoFr
+GoFr makes it easy to use tracing by automatically adding traces to all requests and responses. GoFr uses
+[OpenTelemetry](https://opentelemetry.io/docs/concepts/what-is-opentelemetry/), a popular tracing framework, to
+automatically add traces to all requests and responses.
+
+**Automatic Correlation ID Propagation:**
+
+When a request enters your GoFr application, GoFr automatically generates a correlation ID X-Correlation-ID and adds it 
+to the request headers. This correlation ID is then propagated to all downstream requests. This means that you can track
+a request as it travels through your distributed system by simply looking at the correlation ID in the request headers.
+
+
+### Configuration & Usage
 
   Add Tracer configs in `.env` file, your .env will be updated to
 
@@ -112,12 +123,16 @@ Now that you have created your server, lets see how GoFr by default manages obse
   DB_NAME=test_db
   DB_PORT=3306
 
+  # tracing configs
   TRACER_HOST=localhost
   TRACER_PORT=2005
 
   LOG_LEVEL=DEBUG
   ```
 
-  Open [zipkin](http://localhost:2005/zipkin/) and search by TraceID (correlationID) to see the trace.
+> **NOTE:** If the value of `TRACER_PORT` is not 
+provided, gofr uses port `9411` by default.
+
+Open [zipkin](http://localhost:2005/zipkin/) and search by TraceID (correlationID) to see the trace.
 
 {% figure src="/quick-start-trace.png" alt="Pretty Printed Logs" /%}