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>
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>
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>
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>
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>
This reinstates the behavior of v2.39. The header got messed up in the
sparsehistogram when the change of the version in main was merged into
it (and the merge conflict had to be resolved).
I don't think the current state will actually break anyone, although
it is technically possible. I propose to merge this into the bugfix
branch in any case, but I think we can wait for other bugfixes before
cutting a v2.40.1. (Unless, of course, somebody reports an actual
breakage because of the header.)
Signed-off-by: beorn7 <beorn@grafana.com>
First of all, there was a typo: `encoding=delimited` was a left-over
in the `scrapeAcceptHeader`.
Second, the recently updated `version=1.0.0` prevents current versions
of client_golang to negotiate OpenMetrics, as they expect
`version=0.0.1` or no version at all. This commit adds, with lower
priority, the latter (no version at all) to the accept header.
Fixes#11540,
Signed-off-by: beorn7 <beorn@grafana.com>
* Append metadata to the WAL
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Remove extra whitespace; Reword some docstrings and comments
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Use RLock() for hasNewMetadata check
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Use single byte for metric type in RefMetadata
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Update proposed WAL format for single-byte type metadata
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Address first round of review comments
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Amend description of metadata in wal.md
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Correct key used to retrieve metadata from cache
When we're setting metadata entries in the scrapeCace, we're using the
p.Help(), p.Unit(), p.Type() helpers, which retrieve the series name and
use it as the cache key. When checking for cache entries though, we used
p.Series() as the key, which included the metric name _with_ its labels.
That meant that we were never actually hitting the cache. We're fixing
this by utiling the __name__ internal label for correctly getting the
cache entries after they've been set by setHelp(), setType() or
setUnit().
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Put feature behind a feature flag
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Reorder WAL format document
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Fix CR comments
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Extract logic about changing metadata in an anonymous function
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Implement new proposed WAL format and amend relevant tests
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Use 'const' for metadata field names
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Apply metadata to head memSeries in Commit, not in AppendMetadata
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Add docstring and rename extracted helper in scrape.go
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Fix review comments around TestMetadata* tests
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Rebase with merged TSDB changes; fix duplicate definitions after rebase
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Remove leftover changes on db_test.go
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Rename feature flag
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Simplify updateMetadata helper function
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* Remove extra newline
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
* model/relabel: Add benchmark
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* model/relabel: re-use Builder across relabels
Saves memory allocations.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* labels.Builder: allow re-use of result slice
This reduces memory allocations where the caller has a suitable slice available.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* model/relabel: re-use source values slice
To reduce memory allocations.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Unwind one change causing test failures
Restore original behaviour in PopulateLabels, where we must not overwrite the input set.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* relabel: simplify values optimisation
Use a stack-based array for up to 16 source labels, which will be the
vast majority of cases.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* lint
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Send target and metadata cache in context (again)
The previous attempt was rolled back in #10590 due to memory issues.
`sl.parentCtx` and `sl.ctx` both had a copy of the cache and target info
in the previous attempt and it was hard to pin-point where the context
was being retained causing the memory increase.
I've experimented a bunch in #10627 to figure out that this approach doesn't
cause memory increase. Beyond that, just using this info in _any_ other context
is causing a memory increase.
The change fixed a bunch of long-standing in the OTel Collector that the
community was waiting on and release is blocked on a few downstream distrubutions
of OTel Collector waiting on a fix. I propose to merge this change in while
I investigate what is happening.
Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
* Gate the change behind a manager option
Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
* refactor: move from io/ioutil to io and os packages
* use fs.DirEntry instead of os.FileInfo after os.ReadDir
Signed-off-by: MOREL Matthieu <matthieu.morel@cnp.fr>
OTel Collector prints the following error when a target disappears:
```
2022-04-13T14:20:24.932-0400 warn scrape/scrape.go:1408 Stale append failed {"kind": "receiver", "name": "prometheus", "scrape_pool": "beep-boop", "target": "http://localhost:9090/metrics", "error": "transaction aborted"}
```
This `transaction aborted` error is returned by the custom appender that is
used by the collector when the context of the appender is cancelled:
b7bf11174e/receiver/prometheusreceiver/internal/otlp_transaction.go (L81-L82)
We call `endOfRunStaleness` after `sl.stop()` which cancels `sl.ctx`.
The other `.Appender()` calls use `parentCtx` for the same reason.
This hasn't come up so far because Prometheus' Appender implementation just
ignores the context passed.
Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
Storing the scrape cache and the target (which also contains that cache)
is apparently causing hige memory increase. I think me might not control
the lifespan of the context enough, therefore old objects keep living in
memory for longer than needed.
Let's unblock the release and look for an alternative so that downstream
consumers can get access to that data.
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
* discovery: expose HTTP client options to discoverers
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
* discovery/http: use HTTP client options for created client
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
* scrape: use a list of HTTP client options instead of just dial context
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
* discovery: rephrase comment
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
* scrape: allow providing a custom Dialer for scraping
This commit extends config.ScrapeConfig with an optional field to
override how HTTP connections to targets are created. This field is not
set directly in Prometheus, and is only added for the convenience of
downstream importers.
Closes#9706
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
* scrape: move custom dial function to scrape.Options
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
If reporting metrics fails due to reaching the limit, this makes the
target appear as UP in the UI, but the metrics are missing.
This commit bypasses that limit for report metrics.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
This is to avoid copying the many fields of a histogram.Histogram all
the time.
This also fixes a bunch of formerly broken tests.
Signed-off-by: beorn7 <beorn@grafana.com>
This creates a new `model` directory and moves all data-model related
packages over there:
exemplar labels relabel rulefmt textparse timestamp value
All the others are more or less utilities and have been moved to `util`:
gate logging modetimevfs pool runtime
Signed-off-by: beorn7 <beorn@grafana.com>
* TSDB: demistify seriesRefs and ChunkRefs
The TSDB package contains many types of series and chunk references,
all shrouded in uint types. Often the same uint value may
actually mean one of different types, in non-obvious ways.
This PR aims to clarify the code and help navigating to relevant docs,
usage, etc much quicker.
Concretely:
* Use appropriately named types and document their semantics and
relations.
* Make multiplexing and demuxing of types explicit
(on the boundaries between concrete implementations and generic
interfaces).
* Casting between different types should be free. None of the changes
should have any impact on how the code runs.
TODO: Implement BlockSeriesRef where appropriate (for a future PR)
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
* feedback
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
* agent: demistify seriesRefs and ChunkRefs
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
A lot of this code was hacked together, literally during a
hackathon. This commit intends not to change the code substantially,
but just make the code obey the usual style practices.
A (possibly incomplete) list of areas:
* Generally address linter warnings.
* The `pgk` directory is deprecated as per dev-summit. No new packages should
be added to it. I moved the new `pkg/histogram` package to `model`
anticipating what's proposed in #9478.
* Make the naming of the Sparse Histogram more consistent. Including
abbreviations, there were just too many names for it: SparseHistogram,
Histogram, Histo, hist, his, shs, h. The idea is to call it "Histogram" in
general. Only add "Sparse" if it is needed to avoid confusion with
conventional Histograms (which is rare because the TSDB really has no notion
of conventional Histograms). Use abbreviations only in local scope, and then
really abbreviate (not just removing three out of seven letters like in
"Histo"). This is in the spirit of
https://github.com/golang/go/wiki/CodeReviewComments#variable-names
* Several other minor name changes.
* A lot of formatting of doc comments. For one, following
https://github.com/golang/go/wiki/CodeReviewComments#comment-sentences
, but also layout question, anticipating how things will look like
when rendered by `godoc` (even where `godoc` doesn't render them
right now because they are for unexported types or not a doc comment
at all but just a normal code comment - consistency is queen!).
* Re-enabled `TestQueryLog` and `TestEndopints` (they pass now,
leaving them disabled was presumably an oversight).
* Bucket iterator for histogram.Histogram is now created with a
method.
* HistogramChunk.iterator now allows iterator recycling. (I think
@dieterbe only commented it out because he was confused by the
question in the comment.)
* HistogramAppender.Append panics now because we decided to treat
staleness marker differently.
Signed-off-by: beorn7 <beorn@grafana.com>
We are re-enabling HTTP 2 again. There has been a few bugfixes upstream
in go, and we have also enabled ReadIdleTimeout.
Fix#7588Fix#9068
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Allow to tune the scrape tolerance
In most of the classic monitoring use cases, a few milliseconds
difference can be omitted.
In Prometheus, a few millisecond difference can however make a big
difference.
Currently, Prometheus will ignore up to 2 ms difference in the
alignments.
It turns out that for users who can afford a 10ms difference, there is a
lot of resources and disk space to win, as shown in this graph, which
shows the bytes / samples over a production Prometheus server. You can
clearly see the switch from 2ms to 10ms tolerance.
This pull request enables the adjustment of the scrape timestamp
alignment tolerance.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Fix golint
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Refactor: extract function to make scrapeLoop for testing
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Add benchmarks for ScrapeLoopAppend
For Prometheus and OpenMetrics
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Create less garbage when parsing metrics
Exemplar escapes to heap due to being passed through text-parser
interface, but we can reduce the impact by hoisting it out of the loop
and resetting it after every use.
(Note the cost was paid on every line even when exemplars were disabled)
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Create less garbage when parsing OpenMetrics
After calling parseLVals() we always append the return value, so pass in
what we want to append it to and save garbage.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This adds a new metric exposing per target scrape sample_limit value. Metrics are only exposed if extra-scrape-metrics feature flag is enabled.
scrape_sample_limit will make it easy to monitor and alert on targets getting close to configured sample_limit, which is important given than exceeding sample_limit results in the entire scrape results being rejected.
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
Add a new built-in metric `scrape_timeout_seconds` to allow monitoring
of the ratio of scrape duration to the scrape timeout. Hide behind a
feature flag to avoid additional cardinality by default.
Signed-off-by: SuperQ <superq@gmail.com>
This "brings back" protobuf parsing, with the only goal to play with
the new sparse histograms.
The Prom-2.x style parser is highly adapted to the structure of the
Prometheus text format (and later OpenMetrics). Some jumping through
hoops is required to feed protobuf into it.
This is not meant to be a model for the final implementation. It
should just enable sparse histogram ingestion at a reasonable
efficiency.
Following known shortcomings and flaws:
- No tests yet.
- Summaries and legacy histograms, i.e. without sparse buckets, are
ignored.
- Staleness doesn't work (but this could be fixed in the appender, to
be discussed).
- No tricks have been tried that would be similar to the tricks the
text parsers do (like direct pointers into the HTTP response
body). That makes things weird here. Tricky optimizations only make
sense once the final format is specified, which will almost
certainly not be the old protobuf format. (Interestingly, I expect
this implementation to be in fact much more efficient than the
original protobuf ingestion in Prom-1.x.)
- This is using a proto3 version of metrics.proto (mostly to be
consistent with the other protobuf uses). However, proto3 sees no
difference between an unset field. We depend on that to distinguish
between an unset timestamp and the timestamp 0 (1970-01-01, 00:00:00
UTC). In this experimental code, we just assume that timestamp is
never specified and therefore a timestamp of 0 always is interpreted
as "not set".
Signed-off-by: beorn7 <beorn@grafana.com>
* Write exemplars to the WAL and send them over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Update example for exemplars, print data in a more obvious format.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add metrics for remote write of exemplars.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Fix incorrect slices passed to send in remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* We need to unregister the new metrics.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Order of exemplar append vs write exemplar to WAL needs to change.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Several fixes to prevent sending uninitialized or incorrect samples with an exemplar. Fix dropping exemplar for missing series. Add tests for queue_manager sending exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Store both samples and exemplars in the same timeseries buffer to remove the alloc when building final request, keep sub-slices in separate buffers for re-use
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Condense sample/exemplar delivery tests to parameterized sub-tests
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename test methods for clarity now that they also handle exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename counter variable. Fix instances where metrics were not updated correctly
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Add exemplars to LoadWAL benchmark
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* last exemplars timestamp metric needs to convert value to seconds with
ms precision
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Process exemplar records in a separate go routine when loading the WAL.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments related to clarifying comments and variable
names. Also refactor sample/exemplar to enqueue prompb types.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Regenerate types proto with comments, update protoc version again.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Put remote write of exemplars behind a feature flag.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address some of Ganesh's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Move exemplar remote write feature flag to a config file field.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address Bartek's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Don't allocate exemplar buffers in queue_manager if we're not going to
send exemplars over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add ValidateExemplar function, validate exemplars when appending to head
and log them all to WAL before adding them to exemplar storage.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address more reivew comments from Ganesh.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add exemplar total label length check.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address a few last review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>
* scrape: add label limits per scrape
Add three new limits to the scrape configuration to provide some
mechanism to defend against unbound number of labels and excessive
label lengths. If any of these limits are broken by a sample from a
scrape, the whole scrape will fail. For all of these configuration
options, a zero value means no limit.
The `label_limit` configuration will provide a mechanism to bound the
number of labels per-scrape of a certain sample to a user defined limit.
This limit will be tested against the sample labels plus the discovery
labels, but it will exclude the __name__ from the count since it is a
mandatory Prometheus label to which applying constraints isn't
meaningful.
The `label_name_length_limit` and `label_value_length_limit` will
prevent having labels of excessive lengths. These limits also skip the
__name__ label for the same reasons as the `label_limit` option and will
also make the scrape fail if any sample has a label name/value length
that exceed the predefined limits.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: add metrics and alert to label limits
Add three gauge, one for each label limit to easily access the
limit set by a certain scrape target.
Also add a counter to count the number of targets that exceeded the
label limits and thus were dropped. This is useful for the
`PrometheusLabelLimitHit` alert that will notify the users that scraping
some targets failed because they had samples exceeding the label limits
defined in the scrape configuration.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: apply label limits to __name__ label
Apply limits to the __name__ label that was previously skipped and
truncate the label names and values in the error messages as they can be
very very long.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: remove label limits gauges and refactor
Remove `prometheus_target_scrape_pool_label_limit`,
`prometheus_target_scrape_pool_label_name_length_limit`, and
`prometheus_target_scrape_pool_label_value_length_limit` as they are not
really useful since we don't have the information on the labels in it.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
This moves the label lookup into TSDB, whilst still keeping the cached-ref optimisation for repeated Appends.
This makes the API easier to consume and implement. In particular this change is motivated by the scrape-time-aggregation work, which I don't think is possible to implement without it as it needs access to label values.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
Manager.reload takes the mutex that would make it safe, however
releases it before the goroutines spawned are finished with it.
Thus more explicit locking of scrapePool.Sync/stop/reload is needed.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
Don't lock for all of Sync/stop/reload as that holds up /metrics and the
UI when they want a list of active/dropped targets. Instead take
advantage of the fact that Sync/stop/reload cannot be called
concurrently by the scrape Manager and lock just on the targets
themselves.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
This also fixes a bug in query_log_file, which now is relative to the config file like all other paths.
Signed-off-by: Andy Bursavich <abursavich@gmail.com>
When I started wotking on target_limit, scrapeAndReport did not exist
yet. Then I simply rebased my work without thinking.
It appears that there is a lot that can be inline if I defer() the
report.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
