For: #14355
This commit updates Prometheus to adopt stdlib's log/slog package in
favor of go-kit/log. As part of converting to use slog, several other
related changes are required to get prometheus working, including:
- removed unused logging util func `RateLimit()`
- forward ported the util/logging/Deduper logging by implementing a small custom slog.Handler that does the deduping before chaining log calls to the underlying real slog.Logger
- move some of the json file logging functionality to use prom/common package functionality
- refactored some of the new json file logging for scraping
- changes to promql.QueryLogger interface to swap out logging methods for relevant slog sugar wrappers
- updated lots of tests that used/replicated custom logging functionality, attempting to keep the logical goal of the tests consistent after the transition
- added a healthy amount of `if logger == nil { $makeLogger }` type conditional checks amongst various functions where none were provided -- old code that used the go-kit/log.Logger interface had several places where there were nil references when trying to use functions like `With()` to add keyvals on the new *slog.Logger type
Signed-off-by: TJ Hoplock <t.hoplock@gmail.com>
Snappy remains as the default compression but there is now a flag to switch
the compression algorithm.
Signed-off-by: Justin Lei <justin.lei@grafana.com>
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>
The wlog.WL type can now be used to create a Write Ahead Log or a Write
Behind Log.
Before the prefix for wbl metrics was
'prometheus_tsdb_out_of_order_wal_' and has been replaced with
'prometheus_tsdb_out_of_order_wbl_'.
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
