Metrics - Impressions
Unlaunch SDKs regularly send metrics to Unlaunch servers. These are useful for statistics and debugging purposes.
Metrics are a type of an event. Metric events are automatically generated when feature flags are evaluated on SDKs. Unlaunch SDKs keep a separate queue for metrics and allow fine-grained control over how frequently metrics are submitted to the server, separate from other types of events.
When a feature flag is evaluated on the SDK, an impression capturing the details of the evaluation is generated and recorded by the SDK in a queue. This queue is periodically flushed and events are sent to Unlaunch servers. This information includes the flag details, evaluation results, user information, timestamp etc. These events are then stored in a database. You can view these events in real-time using Live Tail.
Note
We normally keep events for 15-30 days and support custom retention policies. Please email [email protected] for more information.Impression Event fields
Every impression event contains the following fields:
| Key | Description |
|---|---|
| Key | The feature flag key that was evaluated |
| User Id | User Id for which the event was evaluated |
| Variation Key | The variation that was returned |
| Evaluation Reason | Why the particular variation was evaluated e.g. Targeting Rule matched, etc. |
| Flag Status | Whether the flag was enabled or disabled |
| Machine name | Hostname of the machine where feature flag was evaluated |
| SDK Name & Version | The name and version of the SDK |
Adjusting Flush Interval and Queue Size
Server side SDKs send impression events periodically to Unlaunch servers. You can control how often these are sent to the server by setting the metricsFlushInterval() or metricsQueueSize() methods when building the client.