* Drop `AsMarshallable()` from the Metric interface. Use
`json.Marshaler` and `MarshalJSON()`, and leverage JSON struct tags
where possible.
* Add `MarshalJSON()` to Registry and remove `dumpToWriter`, which
makes the registry handler much simpler.
In addition to simplifying some of the marshalling behavior, this also
has the nice side effect of cutting down the number of
`map[string]interface{}` instances.
Examining the existing documentation over the standard Go documentation
server revealed some serious formatting flaws. Everything should be
readable now.
- Comments are migrated from ``/* */`` to ``//`` per convention.
- ``NewDefaultHistogram`` helper.
- ``Registry.Handler`` and ``Registry.YieldExporter`` deprecation.
- Cleanup of legacy import paths.
- Updating examples to use acknowledged patterns.
- Parameterizing the random parameter namespaces for ``examples/random/main.go``, which is useful for demoing population behaviors.
1. The output format is now versioned per the Semantic Versioning scheme. Mainline Prometheus will be adapted to use differing consumption methodologies as the generators' formats evolve to support legacy clients.
2. The telemetry outputter now supports GZIP output encoding. In sample runs, this cuts the output size in half.
3. Basic sanity tests are added for registration with varying levels of pedanticness.
4. We have support for base labels in the registration and emission phases.
5. We have label support for individual metric mutation operations.
6. A number of simplications have been made.
According to the documentation:
// WriteHeader sends an HTTP response header with status code.
// If WriteHeader is not called explicitly, the first call to Write
// will trigger an implicit WriteHeader(http.StatusOK).
// Thus explicit calls to WriteHeader are mainly used to
// send error codes.
and
// Header returns the header map that will be sent by WriteHeader.
// Changing the header after a call to WriteHeader (or Write) has
// no effect.
so calling `w.Header().Set(contentType, jsonContentType)` after calling
`w.WriteHeader` does not set the content type -- the call can be removed
though as it always set `http.StatusOK` which will be done anyways
Even though Travis does NOT offer a consistent Go platform, I want
to nevertheless simplify the scaffolding scripts around it to make
it easier for other folks to perform pull requests, reviews, etc.
while letting the tests run.
Bernerd Schaefer