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Migrations

Migrating to 2.X

Version 2.X consists of a major rewrite that turns spectator-go into a thin client designed to send metrics through spectatord. As a result some functionality has been moved to other packages or removed.

New

Writers

spectator.Registry now supports different writers. The default writer is writer.UdpWriter which sends metrics to spectatord through UDP.

See Usage > Output Location for more details.

Meters

The following new Meters have been added:

  • meter.MaxGauge
  • meter.Gauge with TTL

Common Tags

A few local environment common tags are now automatically added to all Meters. Their values are read from the environment variables.

Tag Environment Variable
nf.container TITUS_CONTAINER_NAME
nf.process NETFLIX_PROCESS_NAME

Tags from environment variables take precedence over tags passed on code when creating the Config.

Note that common tags sourced by spectatord can't be overwritten.

Config

  • Config is now created through a constructor which throws error if the passed in parameters are not valid.
  • Config members are now private.

Moved

  • Runtime metrics collection has been moved to spectator-go-runtime-metrics. Follow instructions in the README to enable collection.
  • Some types have been moved to different packages. For example, spectator.Counter is now in meter.Counter.

Removed

  • spectator.HttpClient has been removed. Use the standard http.Client instead.
  • spectator.Meters no longer have a Measure() []Measurement function. Meters are now stateless and do not store measurements.
  • spectator.Clock has been removed. Use the standard time package instead. Thus, registry.Clock().Now() calls become time.Now() calls.
  • spectator.Config is simplified and local to this library. There is no longer a need to import the internal configuration library.
  • spectator.Registry no longer has a Start() function. The Registry is now effectively stateless and there is nothing to start other than opening the output location.
  • spectator.Registry no longer has a Stop() function. Instead, use Close() to close the registry. Once the registry is closed, it can't be started again. This is intended for final clean up of sockets or file handles.
  • spectator.Config.IpcTimerRecord has been removed. Use a meter.Timer instead to record Ipc metrics.
  • spectator.MeterFactoryFun has been removed. If you need to create a custom meter you can do so by wrapping one of the meters returned by spectator.Registry.
  • spectator.Registry no longer reports spectator.measurements metrics. Instead, you can use similar metrics from spectatord for visibility.
  • spectator.Registry no longer keeps track of the Meters it creates. This means that you can't get a list of all Meters from the Registry. If you need to keep track of Meters, you can do so in your application code.
  • Percentile* meters no longer support defining min/max values.
  • spectator.Registry no longer allows setting a different logger after creation. A custom logger can be set in the spectator.Config before creating the Registry.
  • File-based configuration is no longer supported.

Migration Steps

  1. Make sure you're not relying on any of the removed functionality.
  2. Update imports for Config and Registry, and use the meters package instead of spectator for Meters.
  3. If you want to collect runtime metrics, add the spectator-go-runtime-metrics library, and follow the instructions in the README.
  4. If you use PercentileDistributionSummary or PercentileTimer, then you need to update your code to use the respective functions provided by the Registry to initialize these meters.
  5. Remove the dependency on the spectator-go internal configuration library - it is no longer required.
  6. There is no longer an option to start() or stop() the Registry at runtime. If you need to configure a Registry that doesn't emit metrics, for testing purposes, you can use the spectator.Config.Location option with none to configure a no-op writer.