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.
Double acquisition of the RLock usually doesn't blow up, but if the
write lock is called for between the two RLock's, we are deadlocked.
This deadlock does not exist in release-0.17, BTW.
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.
For historic reasons we were enforcing a timeout directly
via the TCP dialer. This is no longer necessary for quite a while now.
Switching to context.Context will allow us to properly terminate
requests on shutdown as well.
To evenly distribute scraping load we currently rely on random
jittering. This commit hashes over the target's identity and calculates
a consistent offset. This also ensures that scrape intervals
are constantly spaced between config/target changes.
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.
It's actually happening in several places (and for flags, we use the
standard Go time.Duration...). This at least reduces all our
home-grown parsing to one place (in model).
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.
1. static credentials replaced with defaults.DefaultChainCredentials.
This change ensures that credentials are sourced form all possible
providers available with the aws sdk, in the following order:
env variables, shared awsconfig file in user folder, ec2 instance role.
2. Added a few labels: AvailabilityZone, PublicDns, VpcId (if
available), SubnetId (if in Vpc)
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
Bump timeouts of tests where we don't want I/O timeouts.
Adjust the full channel test to be much more reliable,
by reducing the ingestion timeout from 1ms to 0.
Move defer resp.Body.Close() up to make sure it's called even when the
HTTP request returns something other than 200 or Decoder construction
fails. This avoids leaking and eventually running out of file descriptors.
* Support multiple masters with retries against each master as required.
* Scrape masters' metrics.
* Add role meta label for node/service/master to make it easier for relabeling.
When the test ends, all files matching the watcher's glob are removed
via defer. In that moment, the draining goroutine may still be running
and then detect no files matching the configured glob just before the
test exits.
This is now solved by waiting for the draining goroutine to finish
before leaving the test function and thus causing the deferred file
removal.
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.
Instead of only filling __meta_consul_dc when datacenter is set in
consul_sd_config this change fills the label based on what the agent
reports it's current data center is, if datacenter isn't manually set,
otherwise it uses whatever datacenter was set to.
ReplaceAllString only replaces the matching part of the regex,
the unmatched bits around it are left in place. This is not the
expected or desired behaviour as the replacement string should
be everything.
This may break users dependant on this behaviour, but
what they're doing is still possible.
