Add Honeycomb tracing to all Boulder components which act as
HTTP servers, gRPC servers, or gRPC clients. Add many values
which we currently emit to logs to the trace spans. Add a way to
configure the Honeycomb integration to our config files, and by
default configure all of our tests to "mute" (send nothing).
Followup changes will refine the configuration, attempt to reduce
the new dependency load, and introduce better sampling.
Part of https://github.com/letsencrypt/dev-misc-tickets/issues/218
Unit tests are confirmed to pass:
```
~/go/src/golang.org/x/net$ git log --pretty=format:'%h' -n 1
2180aed
~/go/src/golang.org/x/net$ go test ./...
ok golang.org/x/net/bpf 0.494s
ok golang.org/x/net/context 0.058s
ok golang.org/x/net/context/ctxhttp 0.104s
? golang.org/x/net/dict [no test files]
ok golang.org/x/net/dns/dnsmessage 0.074s
ok golang.org/x/net/html 0.097s
ok golang.org/x/net/html/atom 0.002s
ok golang.org/x/net/html/charset 0.020s
ok golang.org/x/net/http/httpguts 0.028s
ok golang.org/x/net/http/httpproxy 0.003s
ok golang.org/x/net/http2 125.352s
ok golang.org/x/net/http2/h2c 0.015s
? golang.org/x/net/http2/h2i [no test files]
ok golang.org/x/net/http2/hpack 0.042s
ok golang.org/x/net/icmp 0.002s
ok golang.org/x/net/idna 0.012s
? golang.org/x/net/internal/iana [no test files]
ok golang.org/x/net/internal/socket 4.560s
ok golang.org/x/net/internal/socks 0.222s
ok golang.org/x/net/internal/sockstest 0.015s
ok golang.org/x/net/internal/timeseries 0.020s
ok golang.org/x/net/ipv4 0.053s
ok golang.org/x/net/ipv6 0.043s
ok golang.org/x/net/nettest 1.057s
ok golang.org/x/net/netutil 0.819s
ok golang.org/x/net/proxy 0.039s
ok golang.org/x/net/publicsuffix 0.146s
ok golang.org/x/net/trace 0.007s
ok golang.org/x/net/webdav 0.091s
ok golang.org/x/net/webdav/internal/xml 0.010s
ok golang.org/x/net/websocket 0.026s
ok golang.org/x/net/xsrftoken 0.019s
```
* 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.
Aaron Gable
Daniel McCarney