Essentially, just don't try to set a status code and send any error
message in the body once metrics gathering has succeeded. At that
point, the most likely reason for errors is anyway that the client has
disconnected, in which sending an error is moot. The other possible
reason for an error is a problem during metrics encoding. This is
unlikely to happen (it's a coding error here in client_golang in any
case), and if it is happening, the odds are we have already sent
something to the ResponseWriter, which means we cannot set a status
code anymore. The doc comment for HTTPErrorOnError now describes these
circumstances explicitly and recommends to set a logger to report that
kind of error.
This should fix the reason for the infamous `superfluous
response.WriteHeader call` message.
Signed-off-by: beorn7 <beorn@grafana.com>
Also, update the package documentation. The concerns about the global
registry aren't really valid anymore because promauto now also works
with custom registries.
The musings about the http.DefaultMux are more a digression and
shouldn't be in a doc comment.
Signed-off-by: beorn7 <beorn@grafana.com>
Interestingly, methods implicitly forwarded from embedded types are
detected by GoDoc if they are just one level deep. Embedded types in
the embedded type are not recognized. This commit therefore adds
explicit forwarding methods for Collect, Describe, and Reset.
Signed-off-by: beorn7 <beorn@grafana.com>
This is, sadly, the only way to avoid a breaking change. The cost is
that anyone using exemplars has to perform a type assertion. This is,
however, a common pattern where interfaces turn out to need additional
methods in a stable library or only some implementations can provide
the additional methods (AKA "interface upgrade").
Needless to say that in v2 of this library, we'll do things in a more
straight forward way.
Signed-off-by: beorn7 <beorn@grafana.com>
Contrary to the code comment, I see no `basicMetricVec` implementation.
Grep'ing this project shows this is the only reference. So I suspect
it's an outdated comment and can be removed to minimize confusion.
I'm unclear whether other parts of that comment are also incorrect and
need updating.
Signed-off-by: Jeff Widman <jeff@jeffwidman.com>
The `const separatorByte` wasn't used anymore actually. In `vec.go`,
we were using `model.SeparatorByte`, which is better anyway. So remove
the unused constant and initialize `separatorByteSlice` with
`model.SeparatorByte`, too.
Signed-off-by: beorn7 <beorn@grafana.com>
This is a much stronger hash function than fnv64a and comparably fast
(with super-fast assembly implementation for amd64).
Performance is not critical here anyway.
The old fnv64a is kept for vectors, where collision detection is in
place and the weakness of the hashing doesn't matter that much. I
implemented a vector version with xxhash and found that xxhash is
slower in all cases except very very high cardinality (where it is
only slightly faster). Also, ``xxhash.New`` comes with an allocation
of 80 bytes. Thus, to keep vectors alloc-free, we needed to add a
`sync.Pool`, which would have an additional performance overhead.
Signed-off-by: beorn7 <beorn@grafana.com>
This makes the collisions a bit less likely by XOR'ing descIDs rather
than adding them up for the collectorID.
Signed-off-by: beorn7 <beorn@grafana.com>
Flush is another of the methods that will call WriteHeader if it
hasn't happened yet. Since we want to call observeWriteHeader (if
set), we need to do the WriteHeader call already here, similar to what
we have done in Write and ReadFrom.
This commit also adds comments explaining the above to not tempt
developers to remove the WriteHeader call.
Signed-off-by: beorn7 <beorn@grafana.com>
It is perfectly possible that a normal GC happens just before the
forced one. Thus seeing 2 GCs is fine.
Whenever this test failed, it was because two GCs were seen.
Signed-off-by: beorn7 <bjoern@rabenste.in>
This is really lame as it essentially just uses longer times to
wait. The test is still timing-dependent and thus could still
theoretically fail with unlucky scheduling. However, we are testing
something that _is_ about timing. Turning this all into something not
timing-dependent would be first quite involved and second might defeat
the purpose of testing code that is inherently about timing.
Let's see how this works out in practice.
Signed-off-by: beorn7 <bjoern@rabenste.in>
We stopped advertising binary-wide setting of a label quite a while
ago. This doc comment was missed in the cleanup.
Signed-off-by: beorn7 <bjoern@rabenste.in>
tl;dr: Return previous memstats if reading new ones takes longer than
1s.
See the doc comment of NewGoCollector for details.
Signed-off-by: beorn7 <bjoern@rabenste.in>
The previous `float64(math.MaxUint64 + 1)` is too close to
`float64(math.MaxUint64)` to actually overflow as indended.
The counter code is actually converting forward and backward and
compare the original and twice-converted value. On most platform, this
will create a deviation and thus trigger the expected behavior. By
sheer "luck", one might end up with the same value and thus still use
the uint64 representation. Which is OK within the precision we can
expect. But it breaks the test. With this change, the next
representable floating point value greater than the floating point
value used to represent math.MaxUint64 is used.
Signed-off-by: Bjoern Rabenstein <bjoern@rabenste.in>
This allows us to simplify a bunch of code while still supporting the
last four Go minor versions.
We have also run into minor annoyances a couple of times by now to
keep supporting 1.7 and 1.8.
It's time to pull the plug!
Signed-off-by: Bjoern Rabenstein <bjoern@rabenste.in>
The context package is available since Go 1.7 which is the minimal version
supported by client_golang.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
reflect.DeepEqual is not suitable for zero occurrences of repeated
proto messages. This changes the comparison to act on the string
representation of proto messages.
Signed-off-by: beorn7 <beorn@soundcloud.com>
So that also users of those can benefit. Obviously, we will end
updating deprecated functions one day (at latest once v0.10 is out).
Signed-off-by: beorn7 <beorn@soundcloud.com>
This is an attempt to expose
https://github.com/istio/istio/issues/8906 . The failure to do so
makes me believe the error is either already fixed in current
client_golang, or something weird I haven't spotted yet is happening
in the istio code.
Signed-off-by: beorn7 <beorn@soundcloud.com>
it appears there is a copy/paste error in the exponential buckets test failure message which is fixed here.
Signed-off-by: David Worth <dworth@strava.com>
This is in line with
https://prometheus.io/docs/instrumenting/writing_clientlibs/#metric-description-and-help
Since the zero value of a string in Go is `""`, we cannot distinguish
between a Help string not set and an empty Help string. Thus, we just
make it formally optional here with an encouragement to set it in the
doc comment.
In v0.10, the Help string will probably become a "normal" argument of
the constructor rather than a field in an Opts struct.
Signed-off-by: beorn7 <beorn@soundcloud.com>
It now uses the new WrapWith function instead of ConstLabels. Describe
is now implemented via DescribeByCollect.
Signed-off-by: beorn7 <beorn@soundcloud.com>
This unifies both constructors in one with an options argument.
The options argument allows to switch on error reporting, as discussed
in #219.
The change of the contructor signature is breaking, but only mildly
so. Plus, the process collector is rarely used explicitly. I used
Sourcegraph to search for public usages, with the following results:
- 2 occurrences of NewProcessCollectorPIDFn, once in @discordianfish's
glimpse, once in @fabxc's etcd_exporter (deprecated anyway). Both
are Prom veterans and will simply do the one line change if needed.
- 8 occurrences of NewProcessCollector, of which 7 are of the form
NewProcessCollector(os.Getpid(), "")
Thus, it's a very easy change, which I even hinted at in the doc
comment.
Signed-off-by: beorn7 <beorn@soundcloud.com>
The only known external usage of it was in prometheus/pushgateway,
where it was removed by
https://github.com/prometheus/pushgateway/pull/200 .
Originally, the expectation was that users would implement the Metric
interface now and then. As we know now, neither it is happening, nor
would it make a lot of sense. (Users implement the Collector interface
instead.) By now, LabelPairSorter is essentially noise in the already
quite cluttered namespace in the prometheus package.
Signed-off-by: beorn7 <beorn@soundcloud.com>
This is for types we don't want to export but which are used in
different packages within client_golang.
Currently, that's only NormalizeMetricFamilies (used in the prometheus
package and in the testutil package). More to be added as needed.
Signed-off-by: beorn7 <beorn@soundcloud.com>
- Expected text format is now read from an io.Reader.
- Metrics are gathered from a Gatherer.
- Added a convenience wrapper to collect from a Collector.
Signed-off-by: beorn7 <beorn@soundcloud.com>
`testutil` is more in line with stdlib naming conventions.
The package should be below `prometheus` as it only provides utils to
test exposition code, not to test HTTP client code.
Signed-off-by: beorn7 <beorn@soundcloud.com>
So far, if a gauge was named `xxx_count`, and a summary or histogram
`xxx`, this would have led to a legal protobuf exposition but would
have created a name collision on `xxx_count` in the text format and
within the Prometheus server.
Signed-off-by: beorn7 <beorn@soundcloud.com>
Also, clarify in the doc comment.
Previously, the assumption was that inconsistent label dimensions are
violating the exposition format spec. However, especially with the
knowledge that OpenMetrics will explicitly allow inconsistent label
dimensions in expositions, we should allow it in client_golang, too.
Note that registration with proper Descs provided will still check for
consistont label dimensions. However, you can "cheat" with custom
Collectors as you can collect metrics that don't follew the provided
Desc (this will be made more explicit and less cheaty once #47 is
fixed). You can also create expositions with inconsistent label
dimensions by merging Gatherers with the Gatherers slice type. (The
latter is used in the Pushgateway.)
Effectively, normal direct instrumentation will always have consistent
label dimensions in this way, but you can cover special use cases with
custom collectors or merging of different Gatherers.
Signed-off-by: beorn7 <beorn@soundcloud.com>
While not strictly correct, it can easily happen that proto messages
are created that use nil pointers instead of pointers in empty strings
to denote an empty string.
Signed-off-by: beorn7 <beorn@soundcloud.com>
Fixes:
http.go:118: declaration of "part" shadows declaration at http.go:117
http_test.go:50: declaration of "respBody" shadows declaration at http_test.go:25
promhttp/http.go:305: declaration of "part" shadows declaration at promhttp/http.go:304
Signed-off-by: Karsten Weiss <knweiss@gmail.com>
The test case requires the /proc filesystem. The change prevents this skip
message during "go test -v" on platforms other than Linux:
=== RUN TestProcessCollector
--- SKIP: TestProcessCollector (0.00s)
process_collector_test.go:15: skipping TestProcessCollector, procfs not available: could not read /proc: stat /proc: no such file or directory
Signed-off-by: Karsten Weiss <knweiss@gmail.com>
Fixes:
prometheus/http_test.go:117:5⚠️ should use resp.Body.String() instead of string(resp.Body.Bytes()) (S1030) (megacheck)
prometheus/http_test.go:118:56⚠️ should use resp.Body.String() instead of string(resp.Body.Bytes()) (S1030) (megacheck)
Signed-off-by: Karsten Weiss <knweiss@gmail.com>
Finally, I found an easy solution to provide the "evil"
auto-registration without getting death threats from the wardens of Go
purity. The reasoning can be found in the package's doc comment.
In principle, we needed to iterate through all permutations, mirroring
the same that is happening in the code. For lack of time, I only
picked one of the cases currently buggy.
As said, this really needs code generation, should we ever find
ourselves touching this again.
Previously, the pickDelegator function was not returning a
*hijackerDelegator so the return value did not implement the Hijacker
interface. As a result, code that attempts to hijack the connection
would fail when using a type assertion.
All the other cases returned the hijackerDelegator correctly.
Original discussion see
https://github.com/prometheus/client_golang/pull/362 .
Assuming that the most frequently used method of a `Gauge` is `Set`
and the most frequently used method of a `Conuter` is `Inc`, this
separates the implementation of both metric types. `Inc` and integral
`Add` of a counter is now handled in a separate `uint64`. This would
create a race in `Set`, but luckily, there is no `Set` anymore in a
counter.
All attempts to solve above race (to use the same idea for a `Gauge`)
slow down `Set`, So we just stick with the old implementation
(formerly `value`) for `Gauge`.
The idea behind it is described in detail in
https://github.com/prometheus/client_golang/issues/320 .
This commit also updates the example given in
promhttp/instrument_server_test.go , which nicely illustrates the
benefit of this change.
So far, currying could be emulated by creating different metric vec's
with different values in their ConstLabels. This was quite difficult
to grasp - which is essentially what was done in the example mentioned
above. Now that this use case can be solved without ConstLabels, we
can safely declare ConstLabels as rarely used. (Perhaps we can
deprecate them entirely one day, but I'll take a raincheck on that
when the changes of v0.10 have materialized.) This commit thus also
updates the ConstLabel doc comments in the various Opts. (It contained
fairly outdated stuff anyway.)
The "panic in case of error" code was so far in metricVec. This pulls
it up into the exported types like CounterVec. This is code
replication, but it avoids an explicit type conversion. Mostly,
however, this is preparation to make the wrapped metricVec an
interface (required for curried vec's).
Specifically @beorn7 pointed out that the previous implementation had
some shortcomings around large numbers. I've changed the code to match
the suggestion in review, as well as added a few test cases.
MetricVec is un-experted by now. godoc handles that correctly by
showing the methods of the embedded un-exported metricVec with the
exported type (CounterVec, SummaryVec, ...) that embeds metricVec.
This is in preparation for "curried" metric vecs, as discussed.
And it's a good thing anyway. The exported MetricVec was from a time
when I thought people would define own Metric types and then create
Vecs of it. That has never happened.
As it turned out, it's not that esay to guess "common" combination of
interface upgrades. So I decided to just implement all 32 possible
combination of interface upgrades. (Only 16 with Go 1.7 and earlier.)
Clearly, this calls for code generation. But right now, we still need
to find out what's the best form of the code. For later additions,
implementing code generation might be useful.
Note that newDelegator is called for each HTTP request. Thus, this
commit aims to make the upgrade selection quick. (After the type
checks, it's just directly accessing an element in a slice.)
cobolbaby