Merge in go-hclog

vendor/github.com/hashicorp/go-hclog/README.md

@@ -10,8 +10,7 @@ interface for use in development and production environments.
 It provides logging levels that provide decreased output based upon the
 desired amount of output, unlike the standard library `log` package.
 
-It does not provide `Printf` style logging, only key/value logging that is
-exposed as arguments to the logging functions for simplicity.
+It provides `Printf` style logging of values via `hclog.Fmt()`.
 
 It provides a human readable output mode for use in development as well as
 JSON output mode for production.
@@ -100,6 +99,17 @@ requestLogger.Info("we are transporting a request")
 This allows sub Loggers to be context specific without having to thread that
 into all the callers.
 
+### Using `hclog.Fmt()`
+
+```go
+var int totalBandwidth = 200
+appLogger.Info("total bandwidth exceeded", "bandwidth", hclog.Fmt("%d GB/s", totalBandwidth))
+```
+
+```text
+... [INFO ] my-app: total bandwidth exceeded: bandwidth="200 GB/s"
+```
+
 ### Use this with code that uses the standard library logger
 
 If you want to use the standard library's `log.Logger` interface you can wrap

vendor/github.com/hashicorp/go-hclog/int.go

@@ -214,6 +214,8 @@ func (z *intLogger) log(t time.Time, level Level, msg string, args ...interface{
 			case CapturedStacktrace:
 				stacktrace = st
 				continue FOR
+			case Format:
+				val = fmt.Sprintf(st[0].(string), st[1:]...)
 			default:
 				val = fmt.Sprintf("%v", st)
 			}
@@ -294,16 +296,20 @@ func (z *intLogger) logJson(t time.Time, level Level, msg string, args ...interf
 				continue
 			}
 			val := args[i+1]
+			switch sv := val.(type) {
+			case error:
 				// Check if val is of type error. If error type doesn't
 				// implement json.Marshaler or encoding.TextMarshaler
 				// then set val to err.Error() so that it gets marshaled
-			if err, ok := val.(error); ok {
-				switch err.(type) {
+				switch sv.(type) {
 				case json.Marshaler, encoding.TextMarshaler:
 				default:
-					val = err.Error()
+					val = sv.Error()
 				}
+			case Format:
+				val = fmt.Sprintf(sv[0].(string), sv[1:]...)
 			}
+
 			vals[args[i].(string)] = val
 		}
 	}

vendor/github.com/hashicorp/go-hclog/log.go

@@ -37,6 +37,18 @@ const (
 	Error Level = 5
 )
 
+// When processing a value of this type, the logger automatically treats the first
+// argument as a Printf formatting string and passes the rest as the values to be
+// formatted. For example: L.Info(Fmt{"%d beans/day", beans}). This is a simple
+// convience type for when formatting is required.
+type Format []interface{}
+
+// Fmt returns a Format type. This is a convience function for creating a Format
+// type.
+func Fmt(str string, args ...interface{}) Format {
+	return append(Format{str}, args...)
+}
+
 // LevelFromString returns a Level type for the named log level, or "NoLevel" if
 // the level string is invalid. This facilitates setting the log level via
 // config or environment variable by name in a predictable way.

vendor/vendor.json

@@ -1087,10 +1087,10 @@
 			"revisionTime": "2018-02-23T19:15:17Z"
 		},
 		{
-			"checksumSHA1": "fg18dhgqDts2CI/Dz+6v5jX/xow=",
+			"checksumSHA1": "OEBNuHhYGJwXWNyZ2i+sAiOLtDs=",
 			"path": "github.com/hashicorp/go-hclog",
-			"revision": "9b9aacd44f1c18bbf913afa45ecd1cb8ec515713",
-			"revisionTime": "2018-04-02T16:24:28Z"
+			"revision": "ad26ae78d4726a0d9fd16afcdff629babc1fc661",
+			"revisionTime": "2018-04-02T19:56:19Z"
 		},
 		{
 			"checksumSHA1": "y+AeKVZoX0gB+DZW4Arzkb3tTVc=",