retreival.Target contains a mutex. It was copied in the Targets()
call. This potentially can wreak a lot of havoc.
It might even have caused the issues reported as #2266 and #2262 .
Also, remove unused `providers` field in targetSet.
If the config file changes, we recreate all providers (by calling
`providersFromConfig`) and retrieve all targets anew from the newly
created providers. From that perspective, it cannot harm to clean up
the target group map in the targetSet. Not doing so (as it was the
case so far) keeps stale targets around. This mattered if an existing
key in the target group map was not overwritten in the initial fetch
of all targets from the providers. Examples where that mattered:
```
scrape_configs:
- job_name: "foo"
static_configs:
- targets: ["foo:9090"]
- targets: ["bar:9090"]
```
updated to:
```
scrape_configs:
- job_name: "foo"
static_configs:
- targets: ["foo:9090"]
```
`bar:9090` would still be monitored. (The static provider just
enumerates the target groups. If the number of target groups
decreases, the old ones stay around.
```
scrape_configs:
- job_name: "foo"
dns_sd_configs:
- names:
- "srv.name.one.example.org"
```
updated to:
```
scrape_configs:
- job_name: "foo"
dns_sd_configs:
- names:
- "srv.name.two.example.org"
```
Now both SRV records are still monitored. The SRV name is part of the
key in the target group map, thus the new one is just added and the
old ane stays around.
Obviously, this should have tests, and should have tests before, not
only for this case. This is the quick fix. I have created
https://github.com/prometheus/prometheus/issues/1906 to track test
creation.
Fixes https://github.com/prometheus/prometheus/issues/1610 .
This change does just signal a scrape target update to the scraping loop
once an initial target set is fetched.
Before, the scrape pool was directly synced, causing a race against an
uninitialized scrape pool.
Fixes#1703
This change deprecates the `target_groups` option in favor
of `static_configs`. The old configuration is still accepted
but prints a warning.
Configuration loading errors if both options are set.
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.
