feat(pprof): add pprof HTTP server (#807)

- `PPROF_ENABLED=no`
- `PPROF_BLOCK_PROFILE_RATE=0`
- `PPROF_MUTEX_PROFILE_RATE=0`
- `PPROF_HTTP_SERVER_ADDRESS=":6060"`

internal/httpserver/helpers_test.go

@@ -0,0 +1,43 @@
+package httpserver
+
+import (
+	"regexp"
+	"time"
+
+	gomock "github.com/golang/mock/gomock"
+)
+
+func stringPtr(s string) *string                 { return &s }
+func durationPtr(d time.Duration) *time.Duration { return &d }
+
+var _ Logger = (*testLogger)(nil)
+
+type testLogger struct{}
+
+func (t *testLogger) Info(msg string)  {}
+func (t *testLogger) Warn(msg string)  {}
+func (t *testLogger) Error(msg string) {}
+
+var _ gomock.Matcher = (*regexMatcher)(nil)
+
+type regexMatcher struct {
+	regexp *regexp.Regexp
+}
+
+func (r *regexMatcher) Matches(x interface{}) bool {
+	s, ok := x.(string)
+	if !ok {
+		return false
+	}
+	return r.regexp.MatchString(s)
+}
+
+func (r *regexMatcher) String() string {
+	return "regular expression " + r.regexp.String()
+}
+
+func newRegexMatcher(regex string) *regexMatcher {
+	return &regexMatcher{
+		regexp: regexp.MustCompile(regex),
+	}
+}