`lset` escapes to heap due to being passed through the text-parser
interface, so we can reduce garbage by hoisting it out of the loop so
only one allocation is done for every series in a scrape.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The parsing doesn't seem to be perfect as I don't get all classic buckets
possibly another bug found?
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
It's possible (quite common on Kubernetes) to have a service discovery
return thousands of targets then drop most of them in relabel rules.
The main place this data is used is to display in the web UI, where
you don't want thousands of lines of display.
The new limit is `keep_dropped_targets`, which defaults to 0
for backwards-compatibility.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Continue to remove confusion that histogram samples are also samples
and histogram values are also values etc. by renaming float values and
float samples using the same schema as for histograms.
Concretely:
- result → resultFloats (corresponding to resultHistograms)
- pendingResult → pendingFloats (corresponding to pendingHistograms)
- rolledbackResult → rolledbackFloats (corresponding to rolledbackHistograms)
- sample → floatSample (corresponding to histogramSample)
This also order the fields in `collectResultAppender` more
consistently.
Signed-off-by: beorn7 <beorn@grafana.com>
This has become a requirement for native histograms, as a single
histogram sample commonly has many buckets, so that providing many
exemplars makes sense.
Since OM text doesn't support native histograms yet, the test had to
be expanded to also support protobuf test cases.
Signed-off-by: beorn7 <beorn@grafana.com>
I had changed the naming from "jitter" to "offset" in:
cb045c0e4b
...but I forgot to add this file to the commit to complete the renaming,
doing that now.
Signed-off-by: Julius Volz <julius.volz@gmail.com>
In digital communication, "jitter" usually refers to how much a signal deviates
from true periodicity, see https://en.wikipedia.org/wiki/Jitter. The way we are
using the "jitterSeed" in Prometheus does not affect the true periodicity at
all, but just introduces a constant phase shift (or offset) within the period.
So it would be more correct and less confusing to call the "jitterSeed" an
"offsetSeed" instead.
Signed-off-by: Julius Volz <julius.volz@gmail.com>
So far, if a target exposes a histogram with both classic and native
buckets, a native-histogram enabled Prometheus would ignore the
classic buckets. With the new scrape config option
`scrape_classic_histograms` set, both buckets will be ingested,
creating all the series of a classic histogram in parallel to the
native histogram series. For example, a histogram `foo` would create a
native histogram series `foo` and classic series called `foo_sum`,
`foo_count`, and `foo_bucket`.
This feature can be used in a migration strategy from classic to
native histograms, where it is desired to have a transition period
during which both native and classic histograms are present.
Note that two bugs in classic histogram parsing were found and fixed
as a byproduct of testing the new feature:
1. Series created from classic _gauge_ histograms didn't get the
_sum/_count/_bucket prefix set.
2. Values of classic _float_ histograms weren't parsed properly.
Signed-off-by: beorn7 <beorn@grafana.com>
Consider code like:
for i := 0; i < numTargets; i++ {
stopFuncs = append(stopFuncs, func() {
time.Sleep(i*20*time.Millisecond)
})
}
Because the loop variable i is shared by all closures,
all the stopFuncs sleep for numTargets*20 ms.
If the i were made per-iteration, as we are considering
for a future Go release, the stopFuncs would have sleep
durations ranging from 0 to (numTargets-1)*20 ms.
Two tests had code like this and were checking that the
aggregate sleep was at least numTargets*20 ms
("at least as long as the last target slept"). This is only true
today because i == numTarget during all the sleeps.
To keep the code working even if the semantics of this loop
change, this PR computes
d := time.Duration((i+1)*20) * time.Millisecond
outside the closure (but inside the loop body), and then each
closure has its own d. Now the sleeps range from 20 ms
to numTargets*20 ms, keeping the test passing
(and probably behaving closer to the intent of the test author).
The failure being fixed can be reproduced by using the current
Go development branch with
GOEXPERIMENT=loopvar go test
Signed-off-by: Russ Cox <rsc@golang.org>
Refactors textparser test to use a common test utility to create
protobuf representation from MetricFamily
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Wiser coders than myself have come to the conclusion that a `switch`
statement is almost always superior to a statement that includes any
`else if`.
The exceptions that I have found in our codebase are just these two:
* The `if else` is followed by an additional statement before the next
condition (separated by a `;`).
* The whole thing is within a `for` loop and `break` statements are
used. In this case, using `switch` would require tagging the `for`
loop, which probably tips the balance.
Why are `switch` statements more readable?
For one, fewer curly braces. But more importantly, the conditions all
have the same alignment, so the whole thing follows the natural flow
of going down a list of conditions. With `else if`, in contrast, all
conditions but the first are "hidden" behind `} else if `, harder to
spot and (for no good reason) presented differently from the first
condition.
I'm sure the aforemention wise coders can list even more reasons.
In any case, I like it so much that I have found myself recommending
it in code reviews. I would like to make it a habit in our code base,
without making it a hard requirement that we would test on the CI. But
for that, there has to be a role model, so this commit eliminates all
`if else` occurrences, unless it is autogenerated code or fits one of
the exceptions above.
Signed-off-by: beorn7 <beorn@grafana.com>
We haven't updated golint-ci in our CI yet, but this commit prepares
for that.
There are a lot of new warnings, and it is mostly because the "revive"
linter got updated. I agree with most of the new warnings, mostly
around not naming unused function parameters (although it is justified
in some cases for documentation purposes – while things like mocks are
a good example where not naming the parameter is clearer).
I'm pretty upset about the "empty block" warning to include `for`
loops. It's such a common pattern to do something in the head of the
`for` loop and then have an empty block. There is still an open issue
about this: https://github.com/mgechev/revive/issues/810 I have
disabled "revive" altogether in files where empty blocks are used
excessively, and I have made the effort to add individual
`// nolint:revive` where empty blocks are used just once or twice.
It's borderline noisy, though, but let's go with it for now.
I should mention that none of the "empty block" warnings for `for`
loop bodies were legitimate.
Signed-off-by: beorn7 <beorn@grafana.com>
It took a `Labels` where the memory could be re-used, but in practice
this hardly ever benefitted. Especially after converting `relabel.Process`
to `relabel.ProcessBuilder`.
Comparing the parameter to `nil` was a bug; `EmptyLabels` is not `nil`
so the slice was reallocated multiple times by `append`.
Lastly `Builder.Labels()` now estimates that the final size will depend
on labels added and deleted.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Since the Target object was just created in this function, nobody else
has a reference to it and there are no concerns about it being modified
concurrently so we don't need to copy the value.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Includes a rewrite of `resolveConflictingExposedLabels` to use
`labels.Builder.Get`, which simplifies it considerably.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Scraping targets are synced by creating the full set, then adding/removing any which have changed.
This PR speeds up the process of creating the full set.
I added a benchmark for `TargetsFromGroup`; it uses configuration from a typical Kubernetes SD.
The crux of the change is to do relabeling inside labels.Builder instead of converting to labels.Labels and back again for every rule. The change is broken into several commits for easier review.
This is a breaking change to `scrape.PopulateLabels()`, but `relabel.Process` is left as-is, with a new `relabel.ProcessBuilder` option.
Common service discovery mechanisms such as Kubernetes can generate a
lot of target groups, so this function was allocating a lot of memory
which then immediately became garbage. Re-using the structures across
an entire Sync saves effort.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Save work converting to `Labels` then to `Builder`.
`PopulateLabels()` now takes as Builder as input.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This makes all usage of maps in scrape.go consistent.
Also remove comment about unsafe strings, since we don't use them any
more in this package.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Extends Appender.AppendHistogram function to accept the FloatHistogram. TSDB supports appending, querying, WAL replay, for this new type of histogram.
Signed-off-by: Marc Tudurí <marctc@protonmail.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Add API endpoints for getting scrape pool names
This adds api/v1/scrape_pools endpoint that returns the list of *names* of all the scrape pools configured.
Having it allows to find out what scrape pools are defined without having to list and parse all targets.
The second change is adding scrapePool query parameter support in api/v1/targets endpoint, that allows to
filter returned targets by only finding ones for passed scrape pool name.
Both changes allow to query for a specific scrape pool data, rather than getting all the targets for all possible scrape pools.
The problem with api/v1/targets endpoint is that it returns huge amount of data if you configure a lot of scrape pools.
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
* Add a scrape pool selector on /targets page
Current targets page lists all possible targets. This works great if you only have a few scrape pools configured,
but for systems with a lot of scrape pools and targets this slow things down a lot.
Not only does the /targets page load very slowly in such case (waiting for huge API response) but it also take
a long time to render, due to huge number of elements.
This change adds a dropdown selector so it's possible to select only intersting scrape pool to view.
There's also scrapePool query param that will open selected pool automatically.
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
The `yolostring` routine was intended to avoid an allocation when
converting from a `[]byte` to a `string` for map lookup.
However, since 2014 Go has recognized this pattern and does not make
a copy of the data when looking up a map. So the unsafe code is not
necessary.
In line with this, constants like `scrapeHealthMetricName` also become
`[]byte`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Patterned after `Chunk.Iterator()`: pass the old iterator in so it
can be re-used to avoid allocating a new object.
(This commit does not do any re-use; it is just changing all the method
signatures so re-use is possible in later commits.)
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
