The sttp.client4.logging.LoggingBackend can log requests and responses which end successfully or with an exception. It can be created given:

  • a sttp.client4.logging.Logger, which is an integration point with logging libraries. Two such integration that are available with sttp-client is slf4j and scribe (see below), but custom ones can be easily added.

  • a sttp.client4.logging.Log, which constructs messages and performs logging actions. A custom implementation can be provided to change the message content or use dynamic log levels.

By default, the following options are exposed:

  • includeTiming - should the duration of the request be included in the log message

  • beforeCurlInsteadOfShow - before sending a request, instead of a summary of the request to be sent, log the curl command which corresponds to the request

  • logRequestBody - should the request body be logged before sending the request (if the request body can be logged)

  • logRequestHeaders - should the non-sensitive request headers be logged before sending the request

  • logResponseBody - should the response body be logged after receiving a response to the request (if the response body can be replayed)

  • logResponseHeaders - should the non-sensitive response headers be logged

The messages are by default logged on these levels:

  • DEBUG before the request is sent

  • DEBUG when a request completes successfully (with a 1xx/2xx status code)

  • WARN when a request completes successfully (with a 4xx/5xx status code)

  • ERROR when there’s an exception when sending a request

Log levels can be configured when creating the LoggingBackend, or specified independently in a custom implementation of Log.

Using slf4j

To use the slf4j logging backend wrapper, add the following dependency to your project:

"com.softwaremill.sttp.client4" %% "slf4j-backend" % "4.0.0-M16"

There are three backend wrappers available, which log request & response information using a slf4j Logger. To see the logs, you’ll need to use an slf4j-compatible logger implementation, e.g. logback, or use a binding, e.g. log4j-slf4j.

Example usage:

import sttp.client4._
import sttp.client4.logging.slf4j.Slf4jLoggingBackend

val backend = Slf4jLoggingBackend(DefaultSyncBackend())

// Logs:
// 21:14:23.735 [main] INFO sttp.client4.logging.slf4j.Slf4jTimingBackend - Request: GET https://httpbin.org/get, took: 0.795s, response: 200

To create a customised logging backend, see the section on custom backends.

Using scribe

To use the scribe logging backend wrapper, add the following dependency to your project:

"com.softwaremill.sttp.client4" %% "scribe-backend" % "4.0.0-M16"