add debug information for extracted data (#3711)

* fix the promtail-default-config download link in doc

* add debug information for extreacted in stage

* add Debug variable

* format

clients/pkg/logentry/stages/json.go

@@ -1,6 +1,7 @@
 package stages
 
 import (
+	"fmt"
 	"reflect"
 	"time"
 
@@ -163,7 +164,9 @@ func (j *jsonStage) Process(labels model.LabelSet, extracted map[string]interfac
 			extracted[n] = string(jm)
 		}
 	}
-
+	if Debug {
+		level.Debug(j.logger).Log("msg", "extracted data debug in json stage", "extracted data", fmt.Sprintf("%v", extracted))
+	}
 }
 
 // Name implements Stage

clients/pkg/logentry/stages/regex.go

@@ -1,6 +1,7 @@
 package stages
 
 import (
+	"fmt"
 	"reflect"
 	"regexp"
 	"time"
@@ -127,7 +128,9 @@ func (r *regexStage) Process(labels model.LabelSet, extracted map[string]interfa
 			extracted[name] = match[i]
 		}
 	}
-
+	if Debug {
+		level.Debug(r.logger).Log("msg", "extracted data debug in regex stage", "extracted data", fmt.Sprintf("%v", extracted))
+	}
 }
 
 // Name implements Stage

clients/pkg/logentry/stages/replace.go

@@ -2,6 +2,7 @@ package stages
 
 import (
 	"bytes"
+	"fmt"
 	"reflect"
 	"regexp"
 	"text/template"
@@ -160,6 +161,9 @@ func (r *replaceStage) Process(labels model.LabelSet, extracted map[string]inter
 			}
 		}
 	}
+	if Debug {
+		level.Debug(r.logger).Log("msg", "extracted data debug in replace stage", "extracted data", fmt.Sprintf("%v", extracted))
+	}
 }
 
 func (r *replaceStage) getReplacedEntry(matchAllIndex [][]int, input string, td map[string]string, templ *template.Template) (string, map[string]string, error) {