Recording traces

The observability plugin provides two options for starting new spans:

• startSpan() ends the span automatically after the callback function completes, whether it returns normally or throws an error
• startManualSpan() ends the span when you call span.end()

To start a new span:

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// This span ends automatically after the callback completes
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LDObserve.startSpan('fetchData', (span) => {
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  // Your code here
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});

To learn more, read startSpan and startManualSpan.

The observability plugin provides a few options for starting new spans:

• startSpan() starts a new span without making it active
• startActiveSpan() starts a new span, makes it active, and runs a callback function within its context
• startWithHeaders() starts a new span with header context

Here’s an example:

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// This span ends automatically after the callback completes
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LDObserve.startActiveSpan('exampleSpan', (span) => {
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  // Your callback function here
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});

To learn more, read Observe.

The Node.js (server-side) SDK’s observability plugin uses the OpenTelemetry Tracing API to work with spans.

Additionally, it provides the following functions for working with spans:

• setAttributes() sets attributes on the active span
• startWithHeaders() starts a span with information from the request headers
• runWithHeaders() runs a callback with information from the request headers and returns the result

Here’s an example:

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app.get("/start-span-example", (req: Request, res: Response) => {
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  const {span} = LDObserve.startWithHeaders('example-span-a', req.headers);
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  LDObserve.setAttributes({
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    "example-attribute": "example-value",
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  });
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  res.send("Hello World");
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  span.end();
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});
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app.get("/run-span-example", async (req: Request, res: Response) => {
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  await LDObserve.runWithHeaders('example-span-b', req.headers, (span) => {
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    LDObserve.setAttributes({
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      "example-attribute": "example-value",
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    });
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    res.send("Hello World");
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  });
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});

To learn more, read Observe.

To start new spans with in the observability plugin for Python SDK, use start_span. This method is a context manager for creating a new span. By default, it records any exceptions as error events on the span, sets the span’s status appropriately. Exiting the context manager calls the span’s end method.

Here’s how:

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  with observe.start_span("manual-span", attributes={"custom": "value"}) as span:
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      span.set_attribute("my-attribute", "my-value")
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      # Any user defined code I want to capture.

This method requires the name of the span. Optionally, you can pass in attributes and specify whether to record an exception or set the span’s status if there is an exception. To construct the attributes argument, use Attributes from the @opentelemetry/api.

To learn more, read start_span.