85 lines
2.6 KiB
Markdown
85 lines
2.6 KiB
Markdown
---
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stage: none
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group: unassigned
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info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
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---
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# GitLab Developers Guide to service measurement
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You can enable service measurement in order to debug any slow service's execution time, number of SQL calls, garbage collection stats, memory usage, etc.
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## Measuring module
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The measuring module is a tool that allows to measure a service's execution, and log:
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- Service class name
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- Execution time
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- Number of SQL calls
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- Detailed `gc` stats and diffs
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- RSS memory usage
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- Server worker ID
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The measuring module logs these measurements into a structured log called [`service_measurement.log`](../administration/logs.md#service_measurementlog),
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as a single entry for each service execution.
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For GitLab.com, `service_measurement.log` is ingested in Elasticsearch and Kibana as part of our monitoring solution.
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## How to use it
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The measuring module allows you to easily measure and log execution of any service,
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by just prepending `Measurable` in any Service class, on the last line of the file that the class resides in.
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For example, to prepend a module into the `DummyService` class, you would use the following approach:
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```ruby
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class DummyService
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def execute
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# ...
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end
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end
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DummyService.prepend(Measurable)
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```
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In case when you are prepending a module from the `EE` namespace with EE features, you need to prepend Measurable after prepending the `EE` module.
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This way, `Measurable` is at the bottom of the ancestor chain, in order to measure execution of `EE` features as well:
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```ruby
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class DummyService
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def execute
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# ...
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end
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end
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DummyService.prepend_mod_with('DummyService')
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DummyService.prepend(Measurable)
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```
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### Log additional attributes
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In case you need to log some additional attributes, it is possible to define `extra_attributes_for_measurement` in the service class:
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```ruby
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def extra_attributes_for_measurement
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{
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project_path: @project.full_path,
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user: current_user.name
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}
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end
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```
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After the measurement module is injected in the service, it is behind a generic feature flag.
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To actually use it, you need to enable measuring for the desired service by enabling the feature flag.
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### Enabling measurement using feature flags
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In the following example, the `:gitlab_service_measuring_projects_import_service`
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[feature flag](feature_flags/index.md#enabling-a-feature-flag-locally-in-development) is used to enable the measuring feature
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for `Projects::ImportService`.
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From ChatOps:
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```shell
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/chatops run feature set gitlab_service_measuring_projects_import_service true
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```
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