Core: Add loki/logproto dependency (#27124)

* Add grafana/loki dependency and update its dependencies

* Update grpcplugin log_wrapper to implement the latest version of hclog.Logger

* Remove panic handling + test case no longer needed since the source of panics (bug) was fixed

pkg/plugins/backendplugin/grpcplugin/log_wrapper.go

@@ -1,16 +1,20 @@
 package grpcplugin
 
 import (
+	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
 
 	glog "github.com/grafana/grafana/pkg/infra/log"
-	hclog "github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-hclog"
 )
 
 type logWrapper struct {
 	Logger glog.Logger
+
+	name        string
+	impliedArgs []interface{}
 }
 
 func formatArgs(args ...interface{}) []interface{} {
@@ -34,31 +38,84 @@ func formatArgs(args ...interface{}) []interface{} {
 	return res
 }
 
+// Emit a message and key/value pairs at a provided log level
+func (lw logWrapper) Log(level hclog.Level, msg string, args ...interface{}) {
+	switch level {
+	case hclog.Trace:
+		lw.Trace(msg, args...)
+	case hclog.Debug:
+		lw.Debug(msg, args...)
+	case hclog.Info:
+		lw.Info(msg, args...)
+	case hclog.Warn:
+		lw.Warn(msg, args...)
+	case hclog.Error:
+		lw.Error(msg, args...)
+	}
+}
+
+// Emit a message and key/value pairs at the TRACE level
 func (lw logWrapper) Trace(msg string, args ...interface{}) {
 	lw.Logger.Debug(msg, formatArgs(args...)...)
 }
+
+// Emit a message and key/value pairs at the DEBUG level
 func (lw logWrapper) Debug(msg string, args ...interface{}) {
 	lw.Logger.Debug(msg, formatArgs(args...)...)
 }
+
+// Emit a message and key/value pairs at the INFO level
 func (lw logWrapper) Info(msg string, args ...interface{}) {
 	lw.Logger.Info(msg, formatArgs(args...)...)
 }
+
+// Emit a message and key/value pairs at the WARN level
 func (lw logWrapper) Warn(msg string, args ...interface{}) {
 	lw.Logger.Warn(msg, formatArgs(args...)...)
 }
+
+// Emit a message and key/value pairs at the ERROR level
 func (lw logWrapper) Error(msg string, args ...interface{}) {
 	lw.Logger.Error(msg, formatArgs(args...)...)
 }
 
+// Indicate if TRACE logs would be emitted.
 func (lw logWrapper) IsTrace() bool { return true }
+
+// Indicate if DEBUG logs would be emitted.
 func (lw logWrapper) IsDebug() bool { return true }
-func (lw logWrapper) IsInfo() bool  { return true }
-func (lw logWrapper) IsWarn() bool  { return true }
+
+// Indicate if INFO logs would be emitted.
+func (lw logWrapper) IsInfo() bool { return true }
+
+// Indicate if WARN logs would be emitted.
+func (lw logWrapper) IsWarn() bool { return true }
+
+// Indicate if ERROR logs would be emitted.
 func (lw logWrapper) IsError() bool { return true }
 
-func (lw logWrapper) With(args ...interface{}) hclog.Logger {
-	return logWrapper{Logger: lw.Logger.New(args...)}
+// ImpliedArgs returns With key/value pairs
+func (lw logWrapper) ImpliedArgs() []interface{} {
+	return lw.impliedArgs
 }
+
+// Creates a sublogger that will always have the given key/value pairs
+func (lw logWrapper) With(args ...interface{}) hclog.Logger {
+	return logWrapper{
+		Logger:      lw.Logger.New(args...),
+		name:        lw.name,
+		impliedArgs: args,
+	}
+}
+
+// Returns the Name of the logger
+func (lw logWrapper) Name() string {
+	return lw.name
+}
+
+// Create a logger that will prepend the name string on the front of all messages.
+// If the logger already has a name, the new value will be appended to the current
+// name.
 func (lw logWrapper) Named(name string) hclog.Logger {
 	if name == "stdio" {
 		// discard logs from stdio hashicorp/go-plugin gRPC service since
@@ -67,21 +124,37 @@ func (lw logWrapper) Named(name string) hclog.Logger {
 		// discard warn log of "received EOF, stopping recv loop".
 		return hclog.NewNullLogger()
 	}
+
+	if lw.name != "" {
+		name = fmt.Sprintf("%s.%s", lw.name, name)
+	}
+
 	return logWrapper{
-		Logger: lw.Logger.New(),
+		Logger:      lw.Logger.New(),
+		name:        name,
+		impliedArgs: lw.impliedArgs,
 	}
 }
 
+// Create a logger that will prepend the name string on the front of all messages.
+// This sets the name of the logger to the value directly, unlike Named which honor
+// the current name as well.
 func (lw logWrapper) ResetNamed(name string) hclog.Logger {
-	return logWrapper{Logger: lw.Logger.New()}
+	return logWrapper{
+		Logger:      lw.Logger.New(),
+		name:        name,
+		impliedArgs: lw.impliedArgs,
+	}
 }
 
+// No-op. The wrapped logger implementation cannot update the level on the fly.
+func (lw logWrapper) SetLevel(level hclog.Level) {}
+
+// Return a value that conforms to the stdlib log.Logger interface
 func (lw logWrapper) StandardLogger(ops *hclog.StandardLoggerOptions) *log.Logger {
 	return nil
 }
 
-func (lw logWrapper) SetLevel(level hclog.Level) {}
-
 // Return a value that conforms to io.Writer, which can be passed into log.SetOutput()
 func (lw logWrapper) StandardWriter(opts *hclog.StandardLoggerOptions) io.Writer {
 	return ioutil.Discard