This fixes the case where a target provider closes the update
channel and exits before the context is canceled.
This should only be true for the static provider but it's safer
to generally handle this case.
This commit removes the scrapeConfig entirely from Target.
All identity defining parameters are thus immutable now and the mutex
can be removed..
Target identity is now correctly defined by the labels and the full URL.
This in particular includes URL parameters that are not specified in the
label set.
Fingerprint is also removed from hash to remove an unnecessary tight coupling
to the common/model package.
With this commit the scrape pool deduplicates incoming
targets before scraping them. This way multiple target providers
can produce the same target but it will be scraped only once.
This commit updates a target set's scrape configuration
on reload. This will cause all running scrape loops to be
stopped and started again with new parameters.
This commit moves Scraper handling into a separate scrapePool type.
TargetSets only manage TargetProvider lifecycles and sync the
retrieved updates to the scrapePool.
TargetProviders are now expected to send a full initial target set
within 5 seconds. The scrapePools preserve target state across reloads
and only drop targets after the initial set was synced.
We group providers by their scrape configuration. Each provider produces
target groups with an unique identifier.
On stopping a set of target providers we cancel the target providers,
stop scraping the targets and wait for the scrapers to finish.
On configuration reload all provider sets are stopped and new ones
are created. This will make targets disappear briefly on configuration
reload. Potentially scrapes are missed but due to the consistent
scrape intervals implemented recently, the impact is minor.
With recent changes to a Target's internal data representation
updating by fullLabels() assigns the additional default
instance label. This breaks target identity comparison and causes
identical targets from service discovery to be constantly swapped.
So far we were using the InstanceIdentifier to compare equality of targets.
This is not always accurate, for example for the blackbox exporter where the
actual target is in the parameter.
This gives up on the idea to communicate throuh the Append() call (by
either not returning as it is now or returning an error as
suggested/explored elsewhere). Here I have added a Throttled() call,
which has the advantage that it can be called before a whole _batch_
of Append()'s. Scrapes will happen completely or not at all. Same for
rule group evaluations. That's a highly desired behavior (as discussed
elsewhere). The code is even simpler now as the whole ingestion buffer
could be removed.
Logging of throttled mode has been streamlined and will create at most
one message per minute.
nerve's registration format differs from serverset. With this commit
there is now a dedicated treecache file in util,
and two separate files for serverset and nerve.
Reference:
https://github.com/airbnb/nerve
For the SNMP and blackbox exporters where
the ports tends to not be 80/443 and indeed
there may not be a port this makes the relabelling
a bit simpler as you don't have to figure out this
logic exists and strip off the :80.
This is a breaking change for the example configs of
those exporters.
With the blackbox exporter, the instance label will commonly
be used for things other than hostnames so remove this restriction.
https://example.com or https://example.com/probe/me are some examples.
To prevent user error, check that urls aren't provided as targets
when there's no relabelling that could potentically fix them.
The prefixed target provider changed a pointerized target group that was
reused in the wrapped target provider, causing an ever-increasing chain
of source prefixes in target groups from the Consul target provider.
We now make this bug generally impossible by switching the target group
channel from pointer to value type and thus ensuring that target groups
are copied before being passed on to other parts of the system.
I tried to not let the depointerization leak too far outside of the
channel handling (both upstream and downstream) because I tried that
initially and caused some nasty bugs, which I want to minimize.
Fixes https://github.com/prometheus/prometheus/issues/1083
This is with `golint -min_confidence=0.5`.
I left several lint warnings untouched because they were either
incorrect or I felt it was better not to change them at the moment.
merge() closes the channel that handleUpdates() reads from when there
are zero configured target providers in the configuration. In that case,
the for-select loop in handleUpdates() entered a busy loop. It should
exit when the upstream channel is closed.
Include position of same SD mechanisms within the same scrape configuration.
Move unique prefixing out of SD implementations and target manager into
its own interface.
Figuring out what's going on with the new service discovery
and labels is difficult. Add a popover with the labels
to the target table to make things simpler, and help
discovery of potentially useful labels.
TargetProviders may flush some last changes to the target manager
before actually stopping. To properly read those form the channel
the target manager must not be locked while stopping a provider.
