Commit Graph

24 Commits

Author SHA1 Message Date
Marco Jantke 685a3c90d4 fail Gather'ing when label value is not utf8 2017-08-20 00:10:32 +02:00
beorn7 2fee50beaa Remove deprecated features that are esay to replace
That's the "soft" part of the deprecation: Everything that has been
marked deprecated in v0.8 or earlier and is straight-forward to
replace by a non-deprecated way, is removed here.

Sadly, this does not include the HTTP part. We first need to provide a
replacement for HTTP instrumentation (as planned for v0.8) to then
remove the deprecated parts in v0.9.
2016-10-25 18:28:15 +02:00
beorn7 a6321dd0b1 Create a "merge gatherer"
This allows to finally get rid of the infamous injection hook in the
interface. The old SetMetricFamilyInjectionHook still exist as a
deprecated function but is now implemented with the new plumbing under
the hood.

Now that we have multiple Gatherer implementation, I renamed
push.Registry to push.FromGatherer.

This commit also improves the consistency checks, which happened as a
byproduct of the refactoring to allow checking in both the "merge
gatherer" Gatherers as well as in the normal Registry.
2016-08-12 21:34:17 +02:00
beorn7 bc0b2a3b17 Move http stuff in its own package promhttp
To keep backwards compatibility while not creating circular import
chains, some code had to be duplicated. But all functions using it
have been declared deprecated hereby.

The new ways of instrumenting handlers will all go into the new
package, and ultimately, the prometheus package itself will be
completely igorant of HTTP.
2016-08-03 18:06:48 +02:00
beorn7 cf7e1caf17 Create a public registry interface and separate out HTTP exposition
General context and approch
===========================

This is the first part of the long awaited wider refurbishment of
`client_golang/prometheus/...`. After a lot of struggling, I decided
to not go for one breaking big-bang, but cut things into smaller steps
after all, mostly to keep the changes manageable and easy to
review. I'm aiming for having the invasive breaking changes
concentrated in as few steps as possible (ideally one). Some steps
will not be breaking at all, but typically there will be breaking
changes that only affect quite special cases so that 95+% of users
will not be affected. This first step is an example for that, see
details below.

What's happening in this commit?
================================

This step is about finally creating an exported registry
interface. This could not be done by simply export the existing
internal implementation because the interface would be _way_ too
fat. This commit introduces a qutie lean `Registry` interface
(compared to the previous interval implementation). The functions that
act on the default registry are retained (with very few exceptions) so
that most use cases won't see a change. However, several of those are
deprecated now to clean up the namespace in the future.

The default registry is kept in the public variable
`DefaultRegistry`. This follows the example of the http package in the
standard library (cf. `http.DefaultServeMux`, `http.DefaultClient`)
with the same implications. (This pattern is somewhat disputed within
the Go community but I chose to go with the devil you know instead of
creating something more complex or even disallowing any changes to the
default registry. The current approach gives everybody the freedom to
not touch DefaultRegistry or to do everything with a custom registry
to play save.)

Another important part in making the registry lean is the extraction
of the HTTP exposition, which also allows for customization of the
HTTP exposition. Note that the separation of metric collection and
exposition has the side effect that managing the MetricFamily and
Metric protobuf objects in a free-list or pool isn't really feasible
anymore. By now (with better GC in more recent Go versions), the
returns were anyway dimisishing. To be effective at all, scrapes had
to happen more often than GC cycles, and even then most elements of
the protobufs (everything excetp the MetricFamily and Metric structs
themselves) would still cause allocation churn. In a future breaking
change, the signature of the Write method in the Metric interface will
be adjusted accordingly. In this commit, avoiding breakage is more
important.

The following issues are fixed by this commit (some solved "on the
fly" now that I was touching the code anyway and it would have been
stupid to port the bugs):

https://github.com/prometheus/client_golang/issues/46
https://github.com/prometheus/client_golang/issues/100
https://github.com/prometheus/client_golang/issues/170
https://github.com/prometheus/client_golang/issues/205

Documentation including examples have been amended as required.

What future changes does this commit enable?
============================================

The following items are not yet implemented, but this commit opens the
possibility of implementing these independently.

- The separation of the HTTP exposition allows the implementation of
  other exposition methods based on the Registry interface, as known
  from other Prometheus client libraries, e.g. sending the metrics to
  Graphite.
  Cf. https://github.com/prometheus/client_golang/issues/197

- The public `Registry` interface allows the implementation of
  convenience tools for testing metrics collection. Those tools can
  inspect the collected MetricFamily protobufs and compare them to
  expectation. Also, tests can use their own testing instance of a
  registry.
  Cf. https://github.com/prometheus/client_golang/issues/58

Notable non-goals of this commit
================================

Non-goals that will be tackled later
------------------------------------

The following two issues are quite closely connected to the changes in
this commit but the line has been drawn deliberately to address them
in later steps of the refurbishment:

- `InstrumentHandler` has many known problems. The plan is to create a
  saner way to conveniently intrument HTTP handlers and remove the old
  `InstrumentHandler` altogether. To keep breakage low for now, even
  the default handler to expose metrics is still using the old
  `InstrumentHandler`. This leads to weird naming inconsistencies but
  I have deemed it better to not break the world right now but do it
  in the change that provides better ways of instrumenting HTTP
  handlers.
  Cf. https://github.com/prometheus/client_golang/issues/200

- There is work underway to make the whole handling of metric
  descriptors (`Desc`) more intuitive and transparent for the user
  (including an ability for less strict checking,
  cf. https://github.com/prometheus/client_golang/issues/47). That's
  quite invasive from the perspective of the internal code, namely the
  registry. I deliberately kept those changes out of this commit.

- While this commit adds new external dependency, the effort to vendor
  anything within the library that is not visible in any exported
  types will have to be done later.

Non-goals that _might_ be tackled later
---------------------------------------

There is a strong and understandable urge to divide the `prometheus`
package into a number of sub-packages (like `registry`, `collectors`,
`http`, `metrics`, …). However, to not run into a multitude of
circular import chains, this would need to break every single existing
usage of the library. (As just one example, if the ubiquitious
`prometheus.MustRegister` (with more than 2,000 uses on GitHub alone)
is kept in the `prometheus` package, but the other registry concerns
go into a new `registry` package, then the `prometheus` package would
import the `registry` package (to call the actual register method),
while at the same time the `registry` package needs to import the
`prometheus` package to access `Collector`, `Metric`, `Desc` and
more. If we moved `MustRegister` into the `registry` package,
thousands of code lines would have to be fixed (which would be easy if
the world was a mono repo, but it is not). If we moved everything else
the proposed registry package needs into packages of their own, we
would break thousands of other code lines.)

The main problem is really the top-level functions like
`MustRegister`, `Handler`, …, which effectively pull everything into
one package. Those functions are however very convenient for the easy
and very frequent use-cases.

This problem has to be revisited later.

For now, I'm trying to keep the amount of exported names in the
package as low as possible (e.g. I unexported expvarCollector in this
commit because the NewExpvarCollector constructor is enough to export,
and it is now consistent with other collectors, like the goCollector).

Non-goals that won't be tackled anytime soon
--------------------------------------------

Something that I have played with a lot is "streaming collection",
i.e. allow an implementation of the `Registry` interface that collects
metrics incrementally and serves them while doing so. As it has turned
out, this has many many issues and makes the `Registry` interface very
clunky. Eventually, I made the call that it is unlikely we will really
implement streaming collection; and making the interface more clunky
for something that might not even happen is really a big no-no. Note
that the `Registry` interface only creates the in-memory
representation of the metric family protobufs in one go. The
serializaton onto the wire can still be handled in a streaming fashion
(which hasn't been done so far, without causing any trouble, but might
be done in the future without breaking any interfaces).

What are the breaking changes?
==============================

- Signatures of functions pushing to Pushgateway have changed to allow
  arbitrary grouping (which was planned for a long time anyway, and
  now that I had to work on the Push code anyway for the registry
  refurbishment, I finally did it,
  cf. https://github.com/prometheus/client_golang/issues/100).
  With the gained insight that pushing to the default registry is almost
  never the right thing, and now that we are breaking the Push call
  anyway, all the Push functions were moved to their own package,
  which cleans up the namespace and is more idiomatic (pushing
  Collectors is now literally done by `push.Collectors(...)`).

- The registry is doing more consistency checks by default now. Past
  creators of inconsistent metrics could have masked the problem by
  not setting `EnableCollectChecks`. Those inconsistencies will now be
  detected. (But note that a "best effort" metrics collection is now
  possible with `HandlerOpts.ErrorHandling = ContinueOnError`.)

- `EnableCollectChecks` is gone. The registry is now performing some
  of those checks anyway (see previous item), and a registry with all
  of those checks can now be created with `NewPedanticRegistry` (only
  used for testing).

- `PanicOnCollectError` is gone. This behavior can now be configured
  when creating a custom HTTP handler.
2016-08-02 18:46:22 +02:00
beorn7 59f2c7d8b0 Fix a number of minor things.
- Clarify documentation about sorting requirements.
- Add missing histogram support in consistency check.
- Add label sorting to consistency check.
- Improve error messages when reporting a metric.
  (Previously, the metric name was not printed.)
2015-06-09 12:03:07 +02:00
beorn7 a762e0612e Allow the metric family injection hook to merge with existing metric families.
If a metric family returned by the injection hook already exists (with
the same name), then its metrics are simply merged into that metric
family. With enabled collect-time checks, even uniqueness is checked,
but in general, things stay the same that the caller is responsible to
ensure metric consistency.

This fixes https://github.com/prometheus/pushgateway/issues/27 .
2015-03-15 16:34:31 +01:00
Julius Volz 738b69e61a Use non-rewritten Godep imports. 2015-02-27 16:49:40 +01:00
Julius Volz 169c8a68e1 Use godep with import rewriting for vendoring.
The new vendoring was produced by running:

    godep save -r ./examples/... ./prometheus/... ./text/... ./model/... ./extraction/...

Two things to note:

- "extraction/processor0_0_{1,2}_test.go" imported a package from
  "github.com/prometheus/prometheus", all for just one tiny testing
  function. To not have to deal with a circular vendoring dependency, I
  simply replaced the usage of the function by some in-line logic.

- godep grouped the rewritten imports slightly differently for some
  reason, but at least the standard library imports are still in a
  separate section. Not sure if it's worth manually keeping our old
  import grouping scheme or if we should simply use that godep-generated
  one.
2015-02-26 00:47:03 +01:00
Julius Volz 765fdaf37e Update protobuf library package name.
The Golang protocol buffer library has now moved to GitHub:

https://github.com/golang/protobuf

Although "go get"-ing the old package name still works, moving
everything to the new one will make vendoring cleaner.

See also https://github.com/matttproud/golang_protobuf_extensions/pull/7
2015-02-14 00:00:34 +01:00
Bjoern Rabenstein d7f8eb1083 Change "Prometheus Team" to "The Prometheus Authors". 2015-02-02 15:14:36 +01:00
Bjoern Rabenstein 96297bcbae Add a configurable version of InstrumentHandler and InstrumentHandlerFunc.
Also, remove quotes from the Content-type header. It's not illegal to
have quotes there, but they are not needed, and at other places, we
are not using them. So fewer characters and more consistency.

Change-Id: If7a78bde85154163e4426daec493d973213e83e9
2014-07-22 17:40:20 +02:00
Bjoern Rabenstein 5d40912fd2 Complete rewrite of the exposition library.
This rewrite had may backs and forths. In my git repository, it
consists of 35 commits which I cannot group or merge into reasonable
review buckets. Gerrit breaks fundamental git semantics, so I have to
squash the 35 commits into one for the review.

I'll push this not with refs/for/master, but with refs/for/next so
that we can transition after submission in a controlled fashion.

For the review, I recommend to start with looking at godoc and in
particular the many examples. After that, continue with a line-by-line
detailed review. (The big picture is hopefully as expected after
wrapping up the discussion earlier.)

Change-Id: Ib38cc46493a5139ca29d84020650929d94cac850
2014-06-17 14:08:22 +02:00
Bjoern Rabenstein 84dc53148d Enable the Golang client library to create the new text formats.
Most important here is the simple & flat text format, but while I'm on
it, I have also added the text representations for protobufs (which is
purely meant for debugging purposes). I hope my basic idea about
handling those various protocols (and the text package) becomes
clearer now.

Change-Id: I7299853eadc82a426101e907f2b3d4e37f9e4c71
2014-04-25 21:45:04 +02:00
Bjoern Rabenstein 00816363e4 Remove the one duplication of the Tester interface.
Change-Id: Ie17ec3393a7e12e0f27e51b4060aa478a172f612
2014-04-25 20:51:08 +02:00
Matt T. Proud 7efd34a6f8 Optimize fingerprinting and metric locks.
These are all simple changes we should have caught a long time ago:

1. The hashing mechanism for fingerprint label sets should have not
   allocated new objects for the actual hashing---at least not
   egregiously.  This simplifies the hash writing by just byte-
   dumping the string stream into the hasher.

2. The hashing mechanism within the scope of a metric does not care
   about the value of the label keys themselves but only of the label
   values.  The keys can be dropped from the calculation.

3. The locking mechanism for the metrics should not block on hash
   computation but rather solely on the actual mutation or critical
   section reads.

4. For scalar metrics (i.e., ones with niladic label signatures), we
   should rely on a preallocated map versus requesting a new one
   ad hoc.

This is tested with Go 1.1, so the results may yield other values
for us elsewhere:

BEFORE
BenchmarkLabelValuesToSignatureScalar	500000000	         3.97 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabelValuesToSignatureSingle	 5000000	       714 ns/op	      74 B/op	       4 allocs/op
BenchmarkLabelValuesToSignatureDouble	 1000000	      1153 ns/op	     107 B/op	       5 allocs/op
BenchmarkLabelValuesToSignatureTriple	 1000000	      1588 ns/op	     138 B/op	       6 allocs/op
BenchmarkLabelToSignatureScalar	500000000	         3.91 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabelToSignatureSingle	 2000000	       874 ns/op	      92 B/op	       5 allocs/op
BenchmarkLabelToSignatureDouble	 1000000	      1528 ns/op	     139 B/op	       7 allocs/op
BenchmarkLabelToSignatureTriple	 1000000	      2172 ns/op	     186 B/op	       9 allocs/op

AFTER
BenchmarkLabelValuesToSignatureScalar	500000000	         4.36 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabelValuesToSignatureSingle	 5000000	       378 ns/op	      89 B/op	       4 allocs/op
BenchmarkLabelValuesToSignatureDouble	 5000000	       574 ns/op	     142 B/op	       5 allocs/op
BenchmarkLabelValuesToSignatureTriple	 5000000	       758 ns/op	     186 B/op	       6 allocs/op
BenchmarkLabelToSignatureScalar	500000000	         4.06 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabelToSignatureSingle	 5000000	       472 ns/op	     106 B/op	       5 allocs/op
BenchmarkLabelToSignatureDouble	 2000000	       746 ns/op	     174 B/op	       7 allocs/op
BenchmarkLabelToSignatureTriple	 1000000	      1061 ns/op	     235 B/op	       9 allocs/op

In effect, a single metric mutation operation's lookup overhead will
move from Before::iBenchmarkLabelToSignature to
After::BenchmarkLabelValuesToSignature.  This MINIMALLY reduces
1/2 the overhead.  I would be hesitant in reading the memory
allocation statistics, for this was run with the GC still on and
thusly inaccurate per Go benchmarking documentation.

Before::BenchmarkLabelValuesToSignature never existed, so it is not
of any intrinsic value in itself.  That said, the cases that still
rely on LabelToSignature experience consistently a 1/2 drop in time.

Change-Id: Ifc9e69f718af65a59f5be8117473518233258159
2014-04-14 19:06:09 +02:00
Bjoern Rabenstein b83e1b7cad Remove redundant __name__ label from protobuf output.
Change-Id: I72d5dbccb0325d6edf7abe5bca88dc5a6001029c
2014-04-03 15:18:12 +02:00
Bjoern Rabenstein ee34486fa1 Add a low-level MetricFamily injection hook.
This hook is needed for the upcoming push gateway.

Also remove go vet warnings and add test for Handler().

Change-Id: If6c56676c7a0f10c16b4effae7285903f8267616
2014-04-02 19:41:44 +02:00
Julius Volz bb957bc145 Change internal metric name label to __name__.
This also adds a check that forbids any user-supplied metrics to start
with the reserved label name prefix "__".

Change-Id: I2fe94c740b685ad05c4c670613cf2af7b9e1c1c0
2014-03-14 12:28:25 +01:00
Bernerd Schaefer a9b3602cea Register copies the provided baseLabels
This ensures that you can pass the same base label set into multiple
Register() calls, e.g.:

    labels := map[string]string{"key": "value"}
    prometheus.Register("metric_1", "", labels, ...)
    prometheus.Register("metric_2", "", labels, ...)

Change-Id: I951e5c2ed7844c74eb3716d1bf07126ce558f266
2013-09-11 17:38:00 +02:00
Matt T. Proud 4956aea5ac Protocol Buffer negotiation support in handler. 2013-07-01 17:14:58 +02:00
Bernerd Schaefer 71dd60e431 Registry and Metrics implement json.Marshaler
* 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.
2013-04-19 15:07:24 +02:00
Bernerd Schaefer 3433b798b3 Use raw string literals in tests 2013-04-19 15:04:07 +02:00
Matt T. Proud f320d28a6c Rearrange file and package per convention.
WIP - Please review but do not merge.
2013-04-04 15:27:09 +02:00