This simplifies routing at auth proxies such as vmauth to vlselect component,
which serves VMUI - just route all the requests, which start with /select/, to vlselect.
vmalert: retry all errors except 4XX status codes
Retry all errors except 4XX status codes while pushing via remote-write
to the remote storage. Previously, errors like broken connection could
prevent vmalert from retrying the request.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* fix: optimize the preparation of data for the graph
* fix: optimize tooltip rendering
* fix: optimize re-rendering of the chart
* vmui: memory leak fix
app/vmagent/remotewrite: fix vmagent panic on shutdown
Currently, when vmagent is stopping it first flushes pending series in remote write context and proceeds to stop streaming aggregation. This leads to streaming aggregation being unable to write results into pending timeseries (since it is already nil) and panic.
This can lead to losing some aggregation results being lost almost silently.
The fix is reordering flow to first stop streaming aggregation and flush all pending time series after that.
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmctl: add verbose output for docker installations or when TTY isn't available
* app/vmctl: fix tests
* app/vmctl: make vmctl interactive if no tty
* app/vmctl: cleanup
* app/vmctl: add comment
---------
Co-authored-by: Nikolay <nik@victoriametrics.com>
* vmalert: fix nil map assignment
The storage instance with nil map params was created for remote-read purposes.
And before change 7a9ae9de0d this map was ignored in ApplyParams.
Now, it started to be used and vmalert panics in runtime.
The fix properly inits map for at `NewVMStorage` and verifies it is not nil
on assignment in `ApplyParams`.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: add to changelog
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The purpose of the change is too highlight what HA pair is
and how deduplication needs identical labels to be present
in raw samples.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4367
Signed-off-by: hagen1778 <roman@victoriametrics.com>
at arm based CPUs only 9 digits after comma matches for tests.
Especially at holtWinters functions. Since it only takes effect at tests
it makes no sense for changing float prescision at actual functions
The fix addresses a case when vmalert is configured with a group
which has `name`, but doesn't have `rules` configured. In this
case it still returns a `nil` instead of `[]` slice.
Fixing this via current commit.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4221
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Previously the location inside the sendPrometheusError() was logged.
This could make hard investigating error locations via `vm_log_messages_total` metric.
* added backup locking/unlocking against retention policy to vmbackupmanager
Signed-off-by: Alexander Marshalov <_@marshalov.org>
* added docs for new commands
Signed-off-by: Alexander Marshalov <_@marshalov.org>
* fix review comments
Signed-off-by: Alexander Marshalov <_@marshalov.org>
---------
Signed-off-by: Alexander Marshalov <_@marshalov.org>
* feat: improvement of the top queries page
* vmui/docs: enhancements to top queries page
* Apply suggestions from code review
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
vmui: change default font size to 14px for better readability
vmui: fix bug with missing text on buttons in safari
---------
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* app/vmui: added Labels with the highest number of unique values
* app/vmui: cleanup
* app/vmui: cleanup
* app/vmui: add table description
* app/vmui: fix comment, updated CHANGELOG.md
* app/vmui: disable links
* app/vmui: added actions to the table, it will show values for selected label with the highest number of series
* app/vmui: fix comment
Previously, metric `vmalert_alerting_rules_last_evaluation_series_fetched`
would be set to 0 for const expressions, because const expression do not match
any series. This may result into a confusion: no series were matched but response isn't empty.
The change updates the logic behind metric: if no series were matched but there are samples
in response - use amount of samples as number of series.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: expand rule groups on anchor click
before, anchor click was only updating the URL.
To expand the group, user had to click on rule's block.
Now, group will toggle automatically.
* vmalert: allow filtering group in web UI
The new filter allows to filter groups and rules within
groups by: errors only or noMatch only.
The filtering supposed to help navigating big numbers of groups/rules.
Filtering is reflected in URL, so can be shared as a link.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Without reset, labels duplicates could have been added during stream aggregation.
Since `ctx.Labels` is reused during processing of many series, each series will
add its labels to the context. Even if the same labels were already addeded on prev
iteration. Now, we reset `ctx.Labels` on each iteration to contain so labels from
different series didn't interfere.
This could have cause exceeding of the limit on number of labels per pushed time series.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4277
Signed-off-by: hagen1778 <roman@victoriametrics.com>
app/vmalert: detect alerting rules which don't match any series at all
vmalert starts to understand /query responses which contain object:
```
"stats":{"seriesFetched": "42"}
```
If object is present, vmalert parses it and populates a new field
`SeriesFetched`. This field is then used to populate the new metric
`vmalert_alerting_rules_last_evaluation_series_fetched` and to
display warnings in the vmalert's UI.
If response doesn't contain the new object (Prometheus or
VictoriaMetrics earlier than v1.90), then `SeriesFetched=nil`.
In this case, UI will contain no additional warnings.
And `vmalert_alerting_rules_last_evaluation_series_fetched` will
be set to `-1`. Negative value of the metric will help to compile
correct alerting rule in follow-up.
Thanks for the initial implementation to @Haleygo
See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4056
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4039
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmselect: exit early from queue on context cancel
When `-search.maxConcurrentRequests` is reached, vmselect puts
request in the queue. It is expected, that requests in the queue
will be processed as soon as it would be enough capacity to do so.
However, it could happen that while request was waiting its turn,
the client could have already cancel it (close the connection,
or just close the tab with UI). In this case, we should de-queue
such requests to avoid spending extra resources on them.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* app/vmselect: address review comments
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Properly return empty slices instead of nil for `/api/v1/rules` and `/api/v1/alerts` API handlers.
This improves compatibility with Grafana.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4221
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Supports using `**` for `-rule` and `-rule.templates`: `dir/**/*.tpl` loads contents of dir and all subdirectories recursively.
See: #4041
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Artem Navoiev <tenmozes@gmail.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
Templating of `-external.alert.source` is not expected to have access to the query which was causing runtime error when query function was passed as nil.
See: #4181
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmagent,lib/persistentqueue: show warning message if `--remoteWrite.maxDiskUsagePerURL` flag lower than 500MB
* app/vmagent,lib/persistentqueue: linter fix
* app/vmagent,lib/persistentqueue: fix comment
* feat: display heatmap in the explore metrics (#4111)
* fix: correct calc step for heatmap
* fix: remove spaces in the result of getDurationFromMilliseconds
* feat: add button "show today" to date picker
* feat: add comparison with the prev day (#3967)
* vmui/docs: add comparison of data to cardinality page
* feat: add WithTemplate page
* app/vmselect/prometheus: enable json mode for expand with expr API
* app/vmselect/prometheus: enable CORS and add content type
* feat: add api for expand with templates
* fix: remove console from useExpandWithExprs
* app/vmselect/prometheus: fix escaping
* vmui: integrate WITH template
* app/vmctl: check content type instead of form param
* fix: add content-type for fetch with-exprs
* fix: add a header to the server's response that allows the "Content-Type" header
* app/vmctl: added comment and cleanup
* app/vmctl: use format query param
---------
Co-authored-by: dmitryk-dk <kozlovdmitriyy@gmail.com>
* app/vmctl: add support for the different time format in the native binary protocol
* app/vmctl: update flag description, update CHANGELOG.md
* app/vmctl: add comment to exported function
* lib/httpserver: introduce `-http.maxConcurrentRequests` command-line flag
Introduce `-http.maxConcurrentRequests` command-line flag to protect
VM components from resource exhaustion during unexpected spikes of HTTP requests.
By default, the new flag's value is set to 0 which means no limits are applied.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/httpserver: mention http.maxConcurrentRequests in docs
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: retry datasource requests with EOF or unexpected EOF errors
Retry failed read request on the closed connection one more time.
This may improve rules execution reliability when connection
between vmalert and datasource closes unexpectedly.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: fix old tests
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Callers of OpenStorage() log the returned error and exit.
The error logging and exit can be performed inside MustOpenStorage()
alongside with printing the stack trace for better debuggability.
This simplifies the code at caller side.
Use fs.MustReadDir() instead of os.ReadDir() across the code in order to reduce the code verbosity.
The fs.MustReadDir() logs the error with the directory name and the call stack on error
before exit. This information should be enough for debugging the cause of the error.
Callers of this function log the returned error and exit.
So let's just log the error with the given filepath and the call stack
inside the function itself and then exit. This simplifies the code
at callers' place while leaves the same level of debuggability in case of errors.
Callers of these functions log the returned error and then exit. The returned error already contains the path
to directory, which was failed to be created. So let's just log the error together with the call stack
inside these functions. This leaves the debuggability of the returned error at the same level
while allows simplifying the code at callers' side.
While at it, properly use MustMkdirFailIfExist instead of MustMkdirIfNotExist inside inmemoryPart.MustStoreToDisk().
It is expected that the inmemoryPart.MustStoreToDick() must fail if there is already a directory under the given path.
Improperly configured -bigMergeConcurrency command-line flag usually leads to uncontrolled
growth of unmerged parts, which, in turn, increases CPU usage and query durations.
So it is better deprecating this flag. In rare cases -smallMergeConcurrency command-line flag
can be used instead for controlling the concurrency of background merges.
* fix: correct display of errors for query
* fix: change the logic of histogram detection
* feat: hide empty buckets from the graph
* fix: revert server url
* feat: add tips for working with the graph and legend
* feat: add the ability to collapse the legend
* vmui/docs: add the ability to collapse the legend
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Make sure that the last successfully loaded config is used on hot-reload failure
- Properly cleanup resources occupied by already initialized aggregators
when the current aggregator fails to be initialized
- Expose distinct vmagent_streamaggr_config_reload* metrics per each -remoteWrite.streamAggr.config
This should simplify monitoring and debugging failed reloads
- Remove race condition at app/vminsert/common.MustStopStreamAggr when calling sa.MustStop() while sa
could be in use at realoadSaConfig()
- Remove lib/streamaggr.aggregator.hasState global variable, since it may negatively impact scalability
on system with big number of CPU cores at hasState.Store(true) call inside aggregator.Push().
- Remove fine-grained aggregator reload - reload all the aggregators on config change instead.
This simplifies the code a bit. The fine-grained aggregator reload may be returned back
if there will be demand from real users for it.
- Check -relabelConfig and -streamAggr.config files when single-node VictoriaMetrics runs with -dryRun flag
- Return back accidentally removed changelog for v1.87.4 at docs/CHANGELOG.md
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3639
- Compare directory names instead of paths to directory when determining which persistent queues must be deleted
This is less error-prone solution, since paths to the same directory can differ, which could lead
to accidental directory removal for the existing -remoteWrite.url
- Log the `removed %d dangling queues` message when at least a single queue has been removed
- Consistently use filepath.Join() for creating paths to persistent queues.
This is needed for Windows support (see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/70 )
- Clarify the description of the change at docs/CHANGELOG.md
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4014
There is a bug here where if you have a single bucket like:
foo{vmrange="4.084e+02...4.642e+02"} 2 123
The expected output is three le encoded buckets like:
foo{le="4.084e+02"} 0 123
foo{le="4.642e+02"} 2 123
foo{le="+Inf"} 2 123
This correctly encodes the start and end of the vmrange.
If however, the input contains the previous bucket, and that bucket is
empty then you only get the end le and +Inf out currently, i.e:
foo{vmrange="7.743e+05...8.799e+05"} 5 123
foo{vmrange="6.813e+05...7.743e+05"} 0 123
results in:
foo{le="8.799e+05"} 5 123
foo{le="+Inf"} 5 123
This causes issues when you go to compute a quantile because this means
that the assumed lower bound of the buckets is 0 and this we interpolate
between 0->end rather than the vmrange start->end as expected.
- Expose stats.seriesFetched at `/api/v1/query_range` responses too
for the sake of consistency.
- Initialize QueryStats when it is needed and pass it to EvalConfig then.
This guarantees that the QueryStats is properly collected when the query
contains some subqueries.
The change adds a new field `seriesFetched` to EvalConfig object.
Since EvalConfig object can be copied inside `Exec`,
`seriesFetched` is a pointer which can be updated by all copied
objects.
The reason for having stats is that other components, like vmalert,
could benefit from this information.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
using `runtime.Gosched` requires acquiring global lock to check if there are any other goroutines to perform tasks. with the latest versions of runtime it can pause running goroutines automatically without requiring to call `Gosched` directly.
Updates #3966
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
- Allocate and initialize seriesByWorkerID slice in a single go instead
of initializing every item in the list separately.
This should reduce CPU usage a bit.
- Properly set anti-false sharing padding at timeseriesWithPadding structure
- Document the change at docs/CHANGELOG.md
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3966
* vmselect/promql: refactor `evalRollupNoIncrementalAggregate` to use lock-less approach for parallel workers computation
Locking there is causing issues when running on highly multi-core system as it introduces lock contention during results merge.
New implementation uses lock less approach to store results per workerID and merges final result in the end, this is expected to significantly reduce lock contention and CPU usage for systems with high number of cores.
Related: #3966
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* vmselect/promql: add pooling for `timeseriesWithPadding` to reduce allocations
Related: #3966
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* vmselect/promql: refactor `evalRollupFuncWithSubquery` to avoid using locks
Uses same approach as `evalRollupNoIncrementalAggregate` to remove locking between workers and reduce lock contention.
Related: #3966
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
This opens the possibility to remove tssLock from evalRollupFuncWithSubquery()
in the follow-up commit from @zekker6 in order to speed up the code
for systems with many CPU cores.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3966
Call runtime.Gosched() only when there is a work to steal from other workers.
Simplify the timeseriesWorker() and unpackWroker() code a bit by inlining stealTimeseriesWork() and stealUnpackWork().
This should reduce CPU usage when processing queries on systems with big number of CPU cores.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3966
* vmalert: support logs suppressing during config reloads
The change is mostly required for ENT version of vmalert,
since it supports object-storage for config files.
Reading data from object storage could be time-consuming,
so vmalert emits logs to track the progress.
However, these logs are mostly needed on start or on
manual config reload. Printing these logs each time
`rule.configCheckInterval` is triggered would too verbose.
So the change allows to control logs emitting during
config reloads.
Now, logs are emitted during start up or when SIGHUP is receieved.
For periodicall config checks logs emitted by config pkg are suppressed.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: review fixes
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
This commit changes background merge algorithm, so it becomes compatible with Windows file semantics.
The previous algorithm for background merge:
1. Merge source parts into a destination part inside tmp directory.
2. Create a file in txn directory with instructions on how to atomically
swap source parts with the destination part.
3. Perform instructions from the file.
4. Delete the file with instructions.
This algorithm guarantees that either source parts or destination part
is visible in the partition after unclean shutdown at any step above,
since the remaining files with instructions is replayed on the next restart,
after that the remaining contents of the tmp directory is deleted.
Unfortunately this algorithm doesn't work under Windows because
it disallows removing and moving files, which are in use.
So the new algorithm for background merge has been implemented:
1. Merge source parts into a destination part inside the partition directory itself.
E.g. now the partition directory may contain both complete and incomplete parts.
2. Atomically update the parts.json file with the new list of parts after the merge,
e.g. remove the source parts from the list and add the destination part to the list
before storing it to parts.json file.
3. Remove the source parts from disk when they are no longer used.
This algorithm guarantees that either source parts or destination part
is visible in the partition after unclean shutdown at any step above,
since incomplete partitions from step 1 or old source parts from step 3 are removed
on the next startup by inspecting parts.json file.
This algorithm should work under Windows, since it doesn't remove or move files in use.
This algorithm has also the following benefits:
- It should work better for NFS.
- It fits object storage semantics.
The new algorithm changes data storage format, so it is impossible to downgrade
to the previous versions of VictoriaMetrics after upgrading to this algorithm.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3236
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3821
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/70
The change also introduces `List` method to `FS` interface.
The `List` method can be used for wildcard support in object storage FS.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
- Sync the description for -httpListenAddr.useProxyProtocol command-line flag at vmagent and vmauth,
so it is consistent with the description at vmauth and victoria-metrics
- Add a sample of panic text to docs/CHANGELOG.md, so it could be googled
- Mention the -httpListenAddr.useProxyProtocol command-line flag in the description for the bugfix
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3335
Each group in vmalert starts with an artifical delay to avoid
thundering herd problem. For some groups with high evaluation
intervals, the delay could be significant.
If during this delay user will remove the group from the config
and hot-reload it - vmalert will have to wait until the delay
ends. This results into slow config reloading and UI hang.
The change moves the start-delay logic back to the group's
`start` method. Now, group can immediately exit from the
delay when `group.close()` method is called.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
app/vmctl: vm-native - split migration on per-metric basis
`vm-native` mode now splits the migration process on per-metric basis.
This allows to migrate metrics one-by-one according to the specified filter.
This change allows to retry export/import requests for a specific metric and provides a better
understanding of the migration progress.
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: hagen1778 <roman@victoriametrics.com>
When group's update() or close() method is called, the group
still need to wait for its current evaluation to finish.
Sometimes, evaluation could take a significant amount of time
which slows configuration update or vmalert's graceful shutdown.
The change interrupts current evaluation in order to speed up
the graceful shutdown or config update procedures.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
- Use flag.Duration instead of flagutil.Duration for -snapshotCreateTimeout,
since the flagutil.Duration is intended mostly for big durations, e.g. days, months and years,
while the -snapshotCreateTimeout is usually smaller than one hour.
- Add links to https://docs.victoriametrics.com/#how-to-work-with-snapshots in docs/CHANGELOG.md,
so readers could easily find the corresponding docs when reading the changelog.
- Properly remove all the created directories on unsuccessful attempt to create
snapshot in Storage.CreateSnapshot().
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3551
* lib/{fs,mergeset,storage}: skip `.must-remove.` dirs when creating snapshot (#3858)
* lib/{mergeset,storage}: add timeout configuration for snapshots creation, remove incomplete snapshots from storage
* docs: fix formatting
* app/vmstorage: add metrics to track status of snapshots
* app/vmstorage: use `vm_http_requests_total` metric for snapshot endpoints metrics, rename new flag to make name more clear
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmstorage: update flag name in docs
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* app/vmstorage: reflect new metrics names change in docs
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Added `victoria-metrics-linux-s390x` to allow single node builds for `s390x` platform.
Leaving other packaging options at the moment, as on this platform, they're mostly going to be built from/with container images hosted within the company as a base, and not alpine.
* vmselect/promql: check for deadline in `count_values` fn
`count_values` could be very slow during the data processing.
Checking for deadline between iterations supposed to reduce
probability of exceeding `search.maxQueryDuration`.
The change also adds a new trace record, which captures the time
spent in aggregation function. Before that, the trace for aggr funcs
could be confusing since it doesn't account for all the places where
time was spent.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* wip
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* metricsql: support optional 2nd argument for rollup functions
Support optional 2nd argument `min`, `max` or `avg` for rollup functions:
* rollup
* rollup_delta
* rollup_deriv
* rollup_increase
* rollup_rate
* rollup_scrape_interval
If second argument is passed, then rollup function will return only the selected aggregation type.
This change can be useful for situations where only one type of rollup calculation is needed.
For example, `rollup_rate(requests_total[5m], "max")`.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* wip
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* feat: improve mobile ui
* feat: improve mobile ui
* fix: change style server url
* fix: improve ExploreMetrics mobile
* fix: display global settings on all pages
- Do not generate __meta_server label, since it is unavailable in Prometheus.
- Add a link to https://docs.victoriametrics.com/sd_configs.html#kuma_sd_configs to docs/CHANGELOG.md,
so users could click it and read the docs without the need to search the corresponding docs.
- Remove kumaTarget struct, since it is easier generating labels for discovered targets
directly from the response returned by Kuma. This simplifies the code.
- Store the generated labels for discovered targets inside atomic.Value. This allows reading them
from concurrent goroutines without the need to use mutex.
- Use synchronouse requests to Kuma instead of long polling, since there is a little sense
in the long polling when the Kuma server may return 304 Not Modified response every -promscrape.kumaSDCheckInterval.
- Remove -promscrape.kuma.waitTime command-line flag, since it is no longer needed when long polling isn't used.
- Set default value for -promscrape.kumaSDCheckInterval to 30s in order to be consistent with Prometheus.
- Remove unnecessary indirections for string literals, which are used only once, in order to improve code readability.
- Remove unused fields from discoveryRequest and discoveryResponse.
- Update tests.
- Document why fetch_timeout and refresh_interval options are missing in kuma_sd_config.
- Add docs to discoveryutils.RequestCallback and discoveryutils.ResponseCallback,
since these are public types.
Side notes: it is weird that Prometheus implementation for kuma_sd_configs sets `instance` label,
since usually this label is set by the Prometheus itself to __address__ after the relabeling phase.
See https://www.robustperception.io/life-of-a-label/
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3389
See https://github.com/prometheus/prometheus/issues/7919
and https://github.com/prometheus/prometheus/pull/8844
as a reference implementation in Prometheus
