Set JournalTarget Priority value to keyword (#2087)

docs/clients/promtail/configuration.md

@@ -661,6 +661,8 @@ labels:
 [path: <string>]
 ```
 
+**Note**: priority label is available as both value and keyword. For example, if `priority` is `3` then the labels will be `__journal_priority` with a value `3` and `__journal_priority_keyword` with a corresponding keyword `err`.
+
 ### syslog_config
 
 The `syslog_config` block configures a syslog listener allowing users to push

pkg/promtail/targets/journaltarget.go

@@ -331,7 +331,32 @@ func (t *JournalTarget) Stop() error {
 func makeJournalFields(fields map[string]string) map[string]string {
 	result := make(map[string]string, len(fields))
 	for k, v := range fields {
+		if k == "PRIORITY" {
+			result[fmt.Sprintf("__journal_%s_%s", strings.ToLower(k), "keyword")] = makeJournalPriority(v)
+		}
 		result[fmt.Sprintf("__journal_%s", strings.ToLower(k))] = v
 	}
 	return result
 }
+
+func makeJournalPriority(priority string) string {
+	switch priority {
+	case "0":
+		return "emerg"
+	case "1":
+		return "alert"
+	case "2":
+		return "crit"
+	case "3":
+		return "error"
+	case "4":
+		return "warning"
+	case "5":
+		return "notice"
+	case "6":
+		return "info"
+	case "7":
+		return "debug"
+	}
+	return priority
+}

pkg/promtail/targets/journaltarget_test.go

@@ -3,6 +3,7 @@
 package targets
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"testing"
@@ -113,7 +114,7 @@ func TestJournalTarget(t *testing.T) {
 		})
 		assert.NoError(t, err)
 	}
-
+	fmt.Println(client.messages)
 	assert.Len(t, client.messages, 10)
 	require.NoError(t, jt.Stop())
 }
@@ -299,3 +300,19 @@ func TestJournalTarget_Cursor_NotTooOld(t *testing.T) {
 	require.Equal(t, r.config.Since, time.Duration(0))
 	require.Equal(t, r.config.Cursor, "foobar")
 }
+
+func Test_MakeJournalFields(t *testing.T) {
+	entryFields := map[string]string{
+		"CODE_FILE":   "journaltarget_test.go",
+		"OTHER_FIELD": "foobar",
+		"PRIORITY":    "6",
+	}
+	receivedFields := makeJournalFields(entryFields)
+	expectedFields := map[string]string{
+		"__journal_code_file":        "journaltarget_test.go",
+		"__journal_other_field":      "foobar",
+		"__journal_priority":         "6",
+		"__journal_priority_keyword": "info",
+	}
+	assert.Equal(t, expectedFields, receivedFields)
+}