Merge pull request #28 from vimeo/min-log-levels

Minimum Log Levels

Fix GKE Emitter with Structured Tags

Fix a bug where only the first structured tag would be emitted in the
gke emitter.

Support Structured Tags

Adds `STags` to `Entry` and delegates marshalling those structures to
the emitters in whatever format is most appropriate.

Structured tags are added via the alog.AddStructuredTags(ctx, sTag1,
sTag2...) function.

Format httpQuery inner values as arrays (#19)

Format httpHeader inner values as arrays (#18)

Pluggable tracing support in gkelog (#17)

* gkelog: Pluggable interface for trace contexts

Split up the existing jsonTrace function so it can use a different
implementation for extracting the trace from the context.

Add support for including the logging.googleapis.com/trace_sampled key
in the logging payload.

reference for structured logs ingested by the stackdriver logging agent
(as used in GKE):
https://cloud.google.com/logging/docs/agent/configuration#special-fields

* Add gitignore with vim excludes

* gkelog: opencensus TraceSpanExtractor

Create a submodule to contain the opencensus TraceSpanExtractor since
that has a rather expansive set of dependencies that we wouldn't want to
force on all users.

* gkelog: add an opentelemetry TraceSpanExtractor

Similar to Opencensus, this one is its own submodule as well.
It locks the current head version of opentelemetry because they renamed
the context-extraction method and I don't want to rename it later.

I had to remove the "sampled" variant of the test because there's
currently no way that I could find to enable sampling without doing
unholy things to the otel SpanContext struct (mostly setting flags
manually).

It looks like they have some missing plumbing, that should get resolved,
so there's a TODO waiting for us when that's working.

Pluggable tracing support in gkelog (#17)

* gkelog: Pluggable interface for trace contexts

Split up the existing jsonTrace function so it can use a different
implementation for extracting the trace from the context.

Add support for including the logging.googleapis.com/trace_sampled key
in the logging payload.

reference for structured logs ingested by the stackdriver logging agent
(as used in GKE):
https://cloud.google.com/logging/docs/agent/configuration#special-fields

* Add gitignore with vim excludes

* gkelog: opencensus TraceSpanExtractor

Create a submodule to contain the opencensus TraceSpanExtractor since
that has a rather expansive set of dependencies that we wouldn't want to
force on all users.

* gkelog: add an opentelemetry TraceSpanExtractor

Similar to Opencensus, this one is its own submodule as well.
It locks the current head version of opentelemetry because they renamed
the context-extraction method and I don't want to rename it later.

I had to remove the "sampled" variant of the test because there's
currently no way that I could find to enable sampling without doing
unholy things to the otel SpanContext struct (mostly setting flags
manually).

It looks like they have some missing plumbing, that should get resolved,
so there's a TODO waiting for us when that's working.

Add Test Emitter (#16)

* add test log emitter option for tests

* code clean up

* go.yml file for actions

* fix race condition, typo, and remove test for sync.Pools (doesn't work before go1.13)

* Update emitter/testlog/emitter.go

Co-Authored-By: dfinkel <david.finkel@gmail.com>

Co-authored-by: dfinkel <david.finkel@gmail.com>

leveled: fix default logger and add a test

gkelog: Prevent duplicate keys in JSON output

Because tags are in the top-level JSON map, we also need to skip
tags with reserved key names that are used internally by gkelog.