public class CallId
Retrieves and generates if necessary a call id. A call id (or correlation id) could be retrieved_ from a call
via CallId.Configuration.retrieve function. Multiple retrieve functions could be configured that will be invoked
one by one until one of them return non-null value. If no value has been provided by retrievers then a generator
could be applied to generate a new call id. Generators could be provided via CallId.Configuration.generate function.
Similar to retrieve, multiple generators could be configured so they will be invoked one by one.
Usually call id is passed via io.ktor.http.HttpHeaders.XRequestId so
one could use CallId.Configuration.retrieveFromHeader function to retrieve call id from a header.
All retrieved or generated call ids are verified against CALL_ID_DEFAULT_DICTIONARY by default. Alternatively
a custom dictionary or functional predicate could be provided via CallId.Configuration.verify that could
pass a valid call id, discard an illegal call id
or reject completely an interface ApplicationCall with HttpStatusCode.BadRequest if an exception RejectedCallIdException is thrown.
Please note that this rejection functionality is not compatible with class StatusPages for now and you cannot
configure rejection response message.
Once a call id is retrieved or generated, it could be accessed via CallIdKt.getCallId otherwise it will be
always null. Also a call id could be replied with response by registering CallId.Configuration.reply or
CallId.Configuration.replyToHeader so client will be able to know call id in case when it is generated.
Please note that call id feature is only intended for debugging and troubleshooting purposes to correlate client requests with logs in multitier/microservices architecture. So usually it is not guaranteed that call id is strictly random/unique. This is why you should NEVER rely on it's uniqueness.
class CallId feature will be installed to CallId.Feature.getPhase into class ApplicationCallPipeline.
CallId.Configuration.retrieve,
CallId.Configuration.generate,
CallId.Configuration.retrieveFromHeader,
CallId.Configuration.verify,
interface ApplicationCall,
exception RejectedCallIdException,
class StatusPages,
CallIdKt.getCallId,
CallId.Configuration.reply,
CallId.Configuration.replyToHeader,
class CallId,
CallId.Feature.getPhase,
class ApplicationCallPipeline| Modifier and Type | Class and Description |
|---|---|
static class |
CallId.Configuration
class CallId feature's configuration |
static class |
CallId.Feature
Installable feature for
class CallId |
| Modifier and Type | Field and Description |
|---|---|
static CallId.Feature |
Feature
Installable feature for
class CallId |
public static CallId.Feature Feature
Installable feature for class CallId
class CallId