Add annotations and metadata to segments with the X-Ray SDK for Python

You can record additional information about requests, the environment, or your application with annotations and metadata. You can add annotations and metadata to the segments that the X-Ray SDK creates, or to custom subsegments that you create.

Annotations are key-value pairs with string, number, or Boolean values. Annotations are indexed for use with filter expressions. Use annotations to record data that you want to use to group traces in the console, or when calling the GetTraceSummaries API.

Metadata are key-value pairs that can have values of any type, including objects and lists, but are not indexed for use with filter expressions. Use metadata to record additional data that you want stored in the trace but don't need to use with search.

In addition to annotations and metadata, you can also record user ID strings on segments. User IDs are recorded in a separate field on segments and are indexed for use with search.

Recording annotations with the X-Ray SDK for Python

Use annotations to record information on segments or subsegments that you want indexed for search.

Annotation Requirements

• Keys – The key for an X-Ray annotation can have up to 500 alphanumeric characters. You cannot use spaces or symbols other than a dot or period ( . )

• Values – The value for an X-Ray annotation can have up to 1,000 Unicode characters.

• The number of Annotations – You can use up to 50 annotations per trace.

To record annotations

1. Get a reference to the current segment or subsegment from xray_recorder.

   from aws_xray_sdk.core import xray_recorder
   ...
   document = xray_recorder.current_segment()

   or

   from aws_xray_sdk.core import xray_recorder
   ...
   document = xray_recorder.current_subsegment()

2. Call put_annotation with a String key, and a Boolean, Number, or String value.

   document.put_annotation("mykey", "my value");

   The following example shows how to call putAnnotation with a String key that includes a dot, and a Boolean, Number, or String value.

   document.putAnnotation("testkey.test", "my value");

Alternatively, you can use the put_annotation method on the xray_recorder. This method records annotations on the current subsegment or, if no subsegment is open, on the segment.

xray_recorder.put_annotation("mykey", "my value");

The SDK records annotations as key-value pairs in an annotations object in the segment document. Calling put_annotation twice with the same key overwrites previously recorded values on the same segment or subsegment.

To find traces that have annotations with specific values, use the annotation[key] keyword in a filter expression.

Recording metadata with the X-Ray SDK for Python

Use metadata to record information on segments or subsegments that you don't need indexed for search. Metadata values can be strings, numbers, Booleans, or any object that can be serialized into a JSON object or array.

To record metadata

1. Get a reference to the current segment or subsegment from xray_recorder.

   from aws_xray_sdk.core import xray_recorder
   ...
   document = xray_recorder.current_segment()

   or

   from aws_xray_sdk.core import xray_recorder
   ...
   document = xray_recorder.current_subsegment()

2. Call put_metadata with a String key; a Boolean, Number, String, or Object value; and a String namespace.

   document.put_metadata("my key", "my value", "my namespace");

   or

   Call put_metadata with just a key and value.

   document.put_metadata("my key", "my value");

Alternatively, you can use the put_metadata method on the xray_recorder. This method records metadata on the current subsegment or, if no subsegment is open, on the segment.

xray_recorder.put_metadata("my key", "my value");

If you don't specify a namespace, the SDK uses default. Calling put_metadata twice with the same key overwrites previously recorded values on the same segment or subsegment.

Recording user IDs with the X-Ray SDK for Python

Record user IDs on request segments to identify the user who sent the request.

To record user IDs

1. Get a reference to the current segment from xray_recorder.

   from aws_xray_sdk.core import xray_recorder
   ...
   document = xray_recorder.current_segment()

2. Call setUser with a String ID of the user who sent the request.

   document.set_user("U12345");

You can call set_user in your controllers to record the user ID as soon as your application starts processing a request.

To find traces for a user ID, use the user keyword in a filter expression.