Logging¶ ↑

The Logger middleware logs both the request and the response body and headers. It is highly customizable and allows to mask confidential information if necessary.

Basic Usage¶ ↑

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger # log requests and responses to $stdout
end

conn.get
# => INFO  -- request: GET http://httpbingo.org/
# => DEBUG -- request: User-Agent: "Faraday v1.0.0"
# => INFO  -- response: Status 301
# => DEBUG -- response: date: "Sun, 19 May 2019 16:05:40 GMT"

Customize the logger¶ ↑

By default, the Logger middleware uses the Ruby Logger.new($stdout). You can customize it to use any logger you want by providing it when you add the middleware to the stack:

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger, MyLogger.new($stdout)
end

Include and exclude headers/bodies¶ ↑

By default, the logger middleware logs only headers for security reasons, however, you can configure it to log bodies and errors as well, or disable headers logging if you need to. To do so, simply provide a configuration hash when you add the middleware to the stack:

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger, nil, { headers: true, bodies: true, errors: true }
end

You can also configure the logger middleware with a little more complex settings like “do not log the request bodies, but log the response bodies”.

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger, nil, { bodies: { request: false, response: true } }
end

Please note this only works with the default formatter.

Filter sensitive information¶ ↑

You can filter sensitive information from Faraday logs using a regex matcher:

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger do | logger |
    logger.filter(/(api_key=)([^&]+)/, '\1[REMOVED]')
  end
end

conn.get('/', api_key: 'secret')
# => INFO  -- request: GET http://httpbingo.org/?api_key=[REMOVED]
# => DEBUG -- request: User-Agent: "Faraday v1.0.0"
# => INFO  -- response: Status 301
# => DEBUG -- response: date: "Sun, 19 May 2019 16:12:36 GMT"

Change log level¶ ↑

By default, the logger middleware logs on the info log level. It is possible to configure the severity by providing the log_level option:

conn = Faraday.new(url: 'http://httpbingo.org') do |faraday|
  faraday.response :logger, nil, { bodies: true, log_level: :debug }
end

Customize the formatter¶ ↑

You can also provide a custom formatter to control how requests, responses and errors are logged. Any custom formatter MUST implement the request and response method, with one argument which will be passed being the Faraday environment. Any custom formatter CAN implement the exception method, with one argument which will be passed being the exception (StandardError). If you make your formatter inheriting from Faraday::Logging::Formatter, then the methods debug, info, warn, error and fatal are automatically delegated to the logger.

class MyFormatter < Faraday::Logging::Formatter
  def request(env)
    # Build a custom message using `env`
    info('Request') { 'Sending Request' }
  end

  def response(env)
    # Build a custom message using `env`
    info('Response') { 'Response Received' }
  end

  def exception(exc)
    # Build a custom message using `exc`
    info('Error') { 'Error Raised' }
  end
end

conn = Faraday.new(url: 'http://httpbingo.org/api_key=s3cr3t') do |faraday|
  faraday.response :logger, nil, formatter: MyFormatter
end