Upgrade grpc to v1.53.0, as preparation for introducing OpenTelemetry,
which depends on that grpc version.
Two changes to our own code were necessitated by upstream changes:
1. Add a stub implementation of GetOrBuildProducer: this was added to
the balancer.SubConn interface by grpc v1.51.0
2. Change use of Endpoint field to Endpoint() method: the field was
removed and replaced by a method in
https://github.com/grpc/grpc-go/pull/5852. This also means that our
tests can't set the .Endpoint field, so the tests are updated to use the
.URL field instead, and a helper has been added to make that easy.
Part of #6361
This is a sort of proof of concept of the Redis interaction, which will
evolve into a tool for inspection and manual repair of missing entries,
if we find ourselves needing to do that.
The important bits here are rocsp/rocsp.go and
cmd/rocsp-tool/main.go. Also, the newly-vendored Redis client.
* cmd: update prometheus.NewProcessCollector args.
There's a new struct `prometheus.ProcessCollectorOpts` that is expected
to be used as the sole argument to `prometheus.NewProcessCollector`. We
don't need to specify `os.Getpid` as the `PidFn` of the struct because
the default is to assume `os.Getpid`. Similarly we don't need to set the
namespace to `""` explicitly, it is the default.
* SA: reimplement db metrics as custom collector.
The modern Prometheus golang API supports translating between legacy
metric sources on the fly with a custom collector. We can use this
approach to collect the metrics from `gorp.DbMap`'s via the `sql.DB`
type's `Stats` function and the returned `sql.DbStats` struct.
This is a cleaner solution overall (we can lose the DB metrics updating
go routine) and it avoids the need to use the now-removed `Set` method
of the `prometheus.Counter` type.
* test: Update CountHistogramSamples.
The `With` function of `prometheus.HistogramVec` types we tend to use as
the argument to `test.CountHistogramSamples` changed to return
a `prometheus.Observer`. Since we only use this function in test
contexts, and only with things that cast back to
a `prometheus.Histogram` we take that approach to fix the problem
without updating call-sites.
Phil Porada