View metrics
Akka projects have this dashboard built-in as part of the Control Tower in the Akka Console. This is available out-of-the-box. You can see metrics such as requests per second, replicas of a service or commands received by a component. The data is grouped into seven categories: Services, Event Sourced Entities, Key Value Entities, Endpoints, Views, Workflows, and Consumers. This is an example of a section within the dashboard.
There are two filters located at the top of the dashboard that allow filtering by service or endpoint.
When filtering by "Service" you are left with only the selected service(s) in the Service and component sections. On top of that, the second filter is reloaded with only the "Endpoints/Methods" belonging to the selected service(s).
"Endpoints/Methods" refers to one thing viewed from different perspectives. An endpoint is created by defining a method inside your service. With an Akka protobuf service via an rcp description and with an Akka Java service via @PostRequest, @PatchRequest or equivalent. The values in "Endpoints/Methods" filter come from the name of your protobuf definition or Java method.
For example, the following class defines and endpoint with the method increaseBy:
public class ... {
@PostMapping("/counter/{counter_id}/increase")
public Effect<Number> increaseBy(@RequestBody Number increaseBy) {
...
}
}This creates an entry increaseBy in the filter Endpoint/Method.
Filtering by "Endpoint/Method" only affect the "Services" Category.
Categories
Services
Successful Requests: Rate of successful requests per second (reqs/s) over time, by endpoint. This is calculated with irate.
Failed Requests: Rate of requests (reqs/s) that raised an error when processing the request, over time, by endpoint. This is calculated with irate.
Processing time distribution(seconds): Number of requests grouped by processing duration, by endpoint. This duration only includes processing inside the Akka service.
Example on how this gauge gets populated: A call that has a duration of 0.05 seconds will increase the counter of the bucket '0.05' and any other bucket with a greater duration.
Processing time distribution: Number of calls that fall into each processing time bucket over time, by endpoint i.e., a histogram of processing time, over time.
Instances: Number of running instances of the service.
Version: A single number, always increasing, shows the service incarnation number. E.g. for a service deployed three times, the value would be 3.
Data ops (read/writes): Total number of reads from the DB by any Akka component of the service(s) and endpoint(s)/method(s) selected. Total number of writes by any Akka component of the selected service(s) and endpoint(s)/method(s) selected.
Event Sourced Entities
Commands received: Rate of commands received per second over time.
Stored events: Total number of events stored per second, over time.
Data ops(reads/writes): Total number of reads when loading from the DB the latest snapshot and the events afterward. Total number of writes when persisting the events or the snapshots generated by the entity.
Processing time quantiles: Quantiles (50, 95 and 99) for the processing time of the commands by the entity.
Key Value Entities
Commands received: Number of commands per second over time.
Data ops(reads/writes): Total number of reads when loading its state from the DB.
Total number of writes when persisting its state in the DB. Processing time distribution(seconds): Idem.
Processing time quantiles: Quantiles (50, 95 and 99) for the processing time of the commands the entity.
Endpoints
Message received: Number of messages per second over time.
Processing time quantiles: Quantiles (50, 95 and 99) for the processing time of the messages by the endpoint.
Views
Data ops(reads/writes): Total number of reads when loading the rows of the view from DB. Total number of writes when upserting the rows of the view on DB.
Workflows
Commands received: Number of commands per second over time.
Data ops(reads/writes): Total number of reads when loading from the DB the latest snapshot and the events afterward. Total number of writes, by workflow, when persisting the events or the snapshots generated by the workflow.
Processing time quantiles: Quantiles (50, 95 and 99) for processing duration by the workflow.
Consumers
Events consumption lag: Quantiles (50, 95, and 95) over time of the consumption of the events produced by a subscription. It can be a subscription to an entity, or to a topic and therefore is grouped by entity or topic.
Instances: Number of running instances of the subscription.
Events consumed: The processing rate of events consumed by a subscription. This is calculated with irate.