Summary:
This diff adds an (as yet unused) option to log verbose scuba samples.
Here's the high-level overview.
In addition to doing `scuba_sample.log_with_msg` and `scuba_sample.log()`, you can now do `scuba_sample.log_with_msg_verbose()` and `scuba_sample.log_verbose()`. These two methods indicate that the intended sample is verbose and should go through some filtering prior to logging.
By default verbose samples are just not logged, but there are ways to override this via `ScubaObservabilityConfig`. Namely, the config has a "system" `ScubaVerbosityLevel`, which is either `Normal` or `Verbose`. When the level is `Verbose`, all samples are logged (those triggered by `.log_with_msg()`, `.log()`, `.log_with_msg_verbose()` and `.log_verbose()`. In addition to the "system" verbosity level, `ScubaObservabilityConfig` supports a few filtering overrides: a list of verbose sessions, a list of verbose unixnames and a list of verbose hostnames. Whenever a verbose sample's session, unixname or source hostname belongs to a corresponding list, the sample is logged.
`ScubaObservabilityConfig` is a struct, queried from `configerator` without the need to restart a service. Querying/figuring out whether logging is needed is done by the `ObservabilityContext` struct, which was introduced a few diffs earlier.
Note: I also want to add regex-based filtering for hostnames, as it's likely to be more useful than exact-match filtering, but I will do that later.
Reviewed By: StanislavGlebik
Differential Revision: D25232429
fbshipit-source-id: 057af95fc31f70d796063cefac5b8f7c69d7b3ef
Summary:
This makes logs go through a `Drain` which queries `ObservabilityContext` (introduced in a previous diff) for current logging level. ATM I did not add any tests, and it's pretty easy to add a unit-test checking that the drain indeed respects the level, but it's so simple that I am not 100% convinced that test would be all that valuable.
Note that currently `ObservabilityContext` is enabled in a `Static` variation.
Reviewed By: mitrandir77
Differential Revision: D25232400
fbshipit-source-id: 7499916e0a3ddab43538343e6ed215818517eaf7
Summary:
`ObservabilityContext` is a structure that helps logging facilities within Mononoke to make logging decisions. Specifically, the upcoming `DynamicLoggingDrain` and already existing `MononokeScubaSampleBuilder` will have this structure as a component and decide whether a particular logging statement (slog or scuba) should go ahead.
Internally, `ObservabilityContext` is a wrapper around data received from a [configerator endpoint](https://www.internalfb.com/intern/configerator/edit/?path=scm%2Fmononoke%2Fobservability%2Fobservability_config.cconf).
This diff makes a few unobvious decisions about how this is organized. My goals were:
1. to have production (i.e. reading from configerator), static (i.e. emulating current prod behavior) and test variants of `ObservabilityContext`
1. to avoid having consumers know which of these variants are used
1. to avoid making all consumers of `ObservabilityContext` necessarily generic
1. to avoid using dynamic dispatch of `ObservabilityContext`'s methods
Points 3 and 4 mean that `ObservabilityContext` cannot be a trait. `enum` is a common solution in such cases. However, if `ObservabilityContext` is an `enum`, consumers will know which variant they are using (because `enum` variants are public). So the solution is to use a private enum wrapped in a struct.
Reviewed By: mitrandir77
Differential Revision: D25287759
fbshipit-source-id: da034c71570137e8a8fb7749b1e4ad43be482f66
