Reporter.File

Reporting to a file.

This reporter logs debugging information about completed requests to a file or stdout (in that case, pass in `devstdout` as the file to log to).

Every line this reporter logs is a JSON string. This 'structured logging' output is optimized for external logging platforms that display these logs in a pretty UI.

This logger supports sampling of successful requests, to help save money when sending logs to external services.

Documentation

report :: Handler -> Text -> TracingSpan -> IO ()

data Handler

handler :: Settings -> IO Handler

Create a Handler for a specified set of Settings. Do this once when your application starts and reuse the Handler you get.

cleanup :: Handler -> IO ()

data Settings

Configuration settings for this reporter. A value of this type can be read from the environment using the decoder function.

decoder :: Decoder Settings

Read Settings from environment variables. Default variables will be used in case no environment variable is set for an option.

logFile :: Settings -> FilePath

The file to log too. On unix systems you can set this to devstdout in order to log to stdout.

environment variable

LOG_FILE

default value

app.log

appName :: Settings -> Text

The name of this application. This will be attached to all logs.

environment variable

LOG_ROOT_NAMESPACE

default value

your-application-name-here

appEnvironment :: Settings -> Text

The environment this application is running in. This will be attached to all logs.

environment variable

ENVIRONMENT

default value

development

fractionOfSuccessRequestsLogged :: Settings -> Float

The fraction of requests that should be logged. Set to 1 if you want to log everything, and a lower value to save money.

environment variable

FRACTION_OF_SUCCESS_REQUESTS_LOGGED

default value

1