The X-Request-ID header
The request ID represented in the HTTP header X-Request-ID let you to link
all the log lines which are common to a single web request.
Definition of the X-Request-ID header
A unique request ID, represented by a UUID, is generated at each HTTP request
received by the platform routing servers. It is added to the request which is
passed to your application containers. The header is called X-Request-ID.
If the X-Request-ID header is already defined by the client, it won’t be
overridden except if it doesn’t respect the following format:
- 20-128 alphanumerical characters and the symbols
+,=,/and-.
Usage in your application
Ruby on Rails
Rails is aware of the X-Request-ID header, you have to configure the logger
to use it. Modify your config/environment/production.rb configuration file:
Before Rails 5.0
config.log_tags = [ :uuid ]
After Rails 5.0:
config.log_tags = [ :request_id ]
Then redeploy your application and you should see the IDs appearing for each request:
2017-05-31 18:42:30 [web-1] [7c129eb1-c479-47bb-9c73-d263e2673026] Started GET "/v1/apps/sample-go-martini/containers" for 62.99.220.106 at 2017-05-31 16:42:30 +0000
2017-05-31 18:42:30 [web-1] [7c129eb1-c479-47bb-9c73-d263e2673026] Processing by App::ContainersController#index as JSON
2017-05-31 18:42:30 [web-1] [7c129eb1-c479-47bb-9c73-d263e2673026] Parameters: {"app_id"=>"sample-go-martini"}
2017-05-31 18:42:30 [web-1] [7c129eb1-c479-47bb-9c73-d263e2673026] Completed 200 OK in 8ms (Views: 1.1ms)
2017-05-31 18:42:30 [web-2] [7742c954-7534-4e76-8828-9e548908958d] Started GET "/v1/apps/sample-go-martini/containers" for 62.99.220.106 at 2017-05-31 16:42:30 +0000
2017-05-31 18:42:30 [web-2] [7742c954-7534-4e76-8828-9e548908958d] Processing by App::ContainersController#index as JSON
2017-05-31 18:42:30 [web-2] [7742c954-7534-4e76-8828-9e548908958d] Parameters: {"app_id"=>"sample-go-martini"}
2017-05-31 18:42:30 [web-1] [9caa8d15-7851-41b0-91c4-512b34f20ea4] Started GET "/v1/apps/sample-go-martini/containers" for 62.99.220.106 at 2017-05-31 16:42:30 +0000
2017-05-31 18:42:30 [web-1] [9caa8d15-7851-41b0-91c4-512b34f20ea4] Processing by App::ContainersController#index as JSON
2017-05-31 18:42:30 [web-1] [9caa8d15-7851-41b0-91c4-512b34f20ea4] Parameters: {"app_id"=>"sample-go-martini"}
2017-05-31 18:42:30 [web-2] [7742c954-7534-4e76-8828-9e548908958d] Completed 200 OK in 7ms (Views: 1.1ms)
2017-05-31 18:42:30 [web-1] [9caa8d15-7851-41b0-91c4-512b34f20ea4] Completed 200 OK in 7ms (Views: 0.9ms)
Node.js
The header will appear in the request object usually named req and you can access it the following way:
req.headers['x-request-id']
If you’re using the package logfmt it will be handled by default with its requestLogger middleware:
app.use(logfmt.requestLogger({immediate: true}, logfmt.commonFormatter))
Other languages
Each language should be able to read the header as it is a standard HTTP header. Don’t hesitate to reach us if you need help getting the header information.