Observability

A module dedicated to observability, that is reporting information about what the program is doing in production to help us debugging it.

Specifically this module is dedicated to sending information that's already been collected to external monitoring platforms, such as Bugsnag and Honeycomb. To learn more about how this information is collected check out the Internal module in the `nri-prelude` package. That module also defines and documents the TracingSpan type, which is the data structure we use to contain observability data we have collected.

Documentation

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

data Handler

A handler for reporting to loggingmonitoringobservability platforms.

The report function takes a span containing all the tracing information we collected for a single request and then reports it to all platforms we enabled when creating this handler.

Instances

Semigroup Handler

Defined in Observability

Methods

(<>) :: Handler -> Handler -> Handler

sconcat :: NonEmpty Handler -> Handler

stimes :: Integral b => b -> Handler -> Handler

Monoid Handler

Defined in Observability

Methods

mempty :: Handler

mappend :: Handler -> Handler -> Handler

mconcat :: [Handler] -> Handler

data Settings

Settings for all supported reporters.

Constructors

Settings

Fields

• enabledReporters :: [Reporter]

  The reporters that we send debugging information to. The first reporter in the list is treated special: it will also report on failures that take place while running any of the other reporters. Because of this its best if the first reporter is one that has a high likelihood of succeeding, for example because it logs to stdout or a file.

• file :: Settings

  Each supported reporter has a settings entry below. We parse settings even for reporters that aren't enabled. Because our environment parser insists all variables have default values it's not necessary to make up values for reporters we don't want enabled.

• bugsnag :: Settings
• honeycomb :: Settings
• dev :: ()

data Reporter where

A helper type that combines all the different functions a specific reporter must implement in a single record.

We've defined this as a GADT so we don't need to expose the handler and settings parameters on the type, meaning this type is defined as Reporter rather than `Reporter settings handler`. This allows us to combine multiple reporters in a list.

Constructors

Reporter

Fields

• :: { reporterName :: Text
•    , reporterSettings :: Settings -> settings

  Pick the reporter-specific settings from the global Settings type defined in this module.

•    , reporterHandler :: settings -> Acquire handler

  Create a handler for this reporter. This function will be called once when the application starts for each enabled reporter.

•    , reporterReport :: handler -> Text -> TracingSpan -> IO ()

  Report a span to this reporter.

•    } -> Reporter

decoder :: Decoder Settings

handler :: Settings -> Acquire Handler

Function for creating an observability handler. The settings we pass in determine which platforms we'll report information to.