Request identification
It is common practise to generate an unique ID for every HTTP request received by a web service. This ID often takes the form of a UUID and can be referred to as a request ID or a correlation ID, among other terms.
These IDs are often generated at the edge of a web architecture in the first server receiving a request from a user (a web page or a public API endpoint) then propagated down through calls to internal services. This allows a single logical request to be traced down through your whole architecture.
Granitic provides an interface httpserver.IdentifiedRequestContextBuilder which allows you to define a component that:
- Generates new IDs or recovers them from an inbound HTTP request
- Store that ID in a new context.Context
- Provide a way of extracting an ID from an existing context
If you create a component that implements httpserver.IdentifiedRequestContextBuilder, it will automatically be injected into your HTTPServer using a decorator.
Default request ID
Granitic can automatically generate a request ID (a V4 UUID) for each request. See the HTTPServer facility documentation for more details.
Accessing the request ID
If your code has access to the ws.Request object, it can
use the ID() function on that object to recover the string representation of the ID, given a context.
The ID will also be automatically be made available to any request instrumentation you have set up and, by using the context key you have used to store the ID in the context, can be logged in application and access logging.
Other code can access the ID, as long as it have access to the context, by invoking the function ws.RequestID(context.Context)
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