Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52

vendor/github.com/go-kit/kit/log/README.md

@@ -0,0 +1,147 @@
+# package log
+
+`package log` provides a minimal interface for structured logging in services.
+It may be wrapped to encode conventions, enforce type-safety, provide leveled
+logging, and so on. It can be used for both typical application log events,
+and log-structured data streams.
+
+## Structured logging
+
+Structured logging is, basically, conceding to the reality that logs are
+_data_, and warrant some level of schematic rigor. Using a stricter,
+key/value-oriented message format for our logs, containing contextual and
+semantic information, makes it much easier to get insight into the
+operational activity of the systems we build. Consequently, `package log` is
+of the strong belief that "[the benefits of structured logging outweigh the
+minimal effort involved](https://www.thoughtworks.com/radar/techniques/structured-logging)".
+
+Migrating from unstructured to structured logging is probably a lot easier
+than you'd expect.
+
+```go
+// Unstructured
+log.Printf("HTTP server listening on %s", addr)
+
+// Structured
+logger.Log("transport", "HTTP", "addr", addr, "msg", "listening")
+```
+
+## Usage
+
+### Typical application logging
+
+```go
+w := log.NewSyncWriter(os.Stderr)
+logger := log.NewLogfmtLogger(w)
+logger.Log("question", "what is the meaning of life?", "answer", 42)
+
+// Output:
+// question="what is the meaning of life?" answer=42
+```
+
+### Contextual Loggers
+
+```go
+func main() {
+	var logger log.Logger
+	logger = log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
+	logger = log.With(logger, "instance_id", 123)
+
+	logger.Log("msg", "starting")
+	NewWorker(log.With(logger, "component", "worker")).Run()
+	NewSlacker(log.With(logger, "component", "slacker")).Run()
+}
+
+// Output:
+// instance_id=123 msg=starting
+// instance_id=123 component=worker msg=running
+// instance_id=123 component=slacker msg=running
+```
+
+### Interact with stdlib logger
+
+Redirect stdlib logger to Go kit logger.
+
+```go
+import (
+	"os"
+	stdlog "log"
+	kitlog "github.com/go-kit/kit/log"
+)
+
+func main() {
+	logger := kitlog.NewJSONLogger(kitlog.NewSyncWriter(os.Stdout))
+	stdlog.SetOutput(kitlog.NewStdlibAdapter(logger))
+	stdlog.Print("I sure like pie")
+}
+
+// Output:
+// {"msg":"I sure like pie","ts":"2016/01/01 12:34:56"}
+```
+
+Or, if, for legacy reasons, you need to pipe all of your logging through the
+stdlib log package, you can redirect Go kit logger to the stdlib logger.
+
+```go
+logger := kitlog.NewLogfmtLogger(kitlog.StdlibWriter{})
+logger.Log("legacy", true, "msg", "at least it's something")
+
+// Output:
+// 2016/01/01 12:34:56 legacy=true msg="at least it's something"
+```
+
+### Timestamps and callers
+
+```go
+var logger log.Logger
+logger = log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
+logger = log.With(logger, "ts", log.DefaultTimestampUTC, "caller", log.DefaultCaller)
+
+logger.Log("msg", "hello")
+
+// Output:
+// ts=2016-01-01T12:34:56Z caller=main.go:15 msg=hello
+```
+
+## Supported output formats
+
+- [Logfmt](https://brandur.org/logfmt) ([see also](https://blog.codeship.com/logfmt-a-log-format-thats-easy-to-read-and-write))
+- JSON
+
+## Enhancements
+
+`package log` is centered on the one-method Logger interface.
+
+```go
+type Logger interface {
+	Log(keyvals ...interface{}) error
+}
+```
+
+This interface, and its supporting code like is the product of much iteration
+and evaluation. For more details on the evolution of the Logger interface,
+see [The Hunt for a Logger Interface](http://go-talks.appspot.com/github.com/ChrisHines/talks/structured-logging/structured-logging.slide#1),
+a talk by [Chris Hines](https://github.com/ChrisHines).
+Also, please see
+[#63](https://github.com/go-kit/kit/issues/63),
+[#76](https://github.com/go-kit/kit/pull/76),
+[#131](https://github.com/go-kit/kit/issues/131),
+[#157](https://github.com/go-kit/kit/pull/157),
+[#164](https://github.com/go-kit/kit/issues/164), and
+[#252](https://github.com/go-kit/kit/pull/252)
+to review historical conversations about package log and the Logger interface.
+
+Value-add packages and suggestions,
+like improvements to [the leveled logger](https://godoc.org/github.com/go-kit/kit/log/level),
+are of course welcome. Good proposals should
+
+- Be composable with [contextual loggers](https://godoc.org/github.com/go-kit/kit/log#With),
+- Not break the behavior of [log.Caller](https://godoc.org/github.com/go-kit/kit/log#Caller) in any wrapped contextual loggers, and
+- Be friendly to packages that accept only an unadorned log.Logger.
+
+## Benchmarks & comparisons
+
+There are a few Go logging benchmarks and comparisons that include Go kit's package log.
+
+- [imkira/go-loggers-bench](https://github.com/imkira/go-loggers-bench) includes kit/log
+- [uber-common/zap](https://github.com/uber-common/zap), a zero-alloc logging library, includes a comparison with kit/log