Fix loading processors from autodiscover hints (#16348)

* Parse processors from hints as JSON.

* Add test.

* Add changelog entry.

CHANGELOG.next.asciidoc

@@ -56,6 +56,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Upgrade go-ucfg to latest v0.8.1. {pull}15937{15937}
 - Fix index names for indexing not always guaranteed to be lower case. {pull}16081[16081]
 - Add `ssl.ca_sha256` option to the supported TLS option, this allow to check that a specific certificate is used as part of the verified chain. {issue}15717[15717]
+- Fix loading processors from annotation hints. {pull}16348[16348]
 
 *Auditbeat*
 

libbeat/autodiscover/builder/helper.go

@@ -86,7 +86,20 @@ func GetHintAsList(hints common.MapStr, key, config string) []string {
 
 // GetProcessors gets processor definitions from the hints and returns a list of configs as a MapStr
 func GetProcessors(hints common.MapStr, key string) []common.MapStr {
-	return GetConfigs(hints, key, "processors")
+	processors := GetConfigs(hints, key, "processors")
+	for _, proc := range processors {
+		for key, value := range proc {
+			if str, ok := value.(string); ok {
+				cfg := common.MapStr{}
+				if err := json.Unmarshal([]byte(str), &cfg); err != nil {
+					logp.Debug("autodiscover.builder", "unable to unmarshal json due to error: %v", err)
+					continue
+				}
+				proc[key] = cfg
+			}
+		}
+	}
+	return processors
 }
 
 // GetConfigs takes in a key and returns a list of configs as a slice of MapStr

libbeat/autodiscover/builder/helper_test.go

@@ -25,6 +25,30 @@ import (
 	"github.com/elastic/beats/libbeat/common"
 )
 
+func TestGetProcessors(t *testing.T) {
+	hints := common.MapStr{
+		"co": common.MapStr{
+			"elastic": common.MapStr{
+				"logs": common.MapStr{
+					"processors": common.MapStr{
+						"add_fields": `{"fields": {"foo": "bar"}}`,
+					},
+				},
+			},
+		},
+	}
+	procs := GetProcessors(hints, "co.elastic.logs")
+	assert.Equal(t, []common.MapStr{
+		common.MapStr{
+			"add_fields": common.MapStr{
+				"fields": map[string]interface{}{
+					"foo": "bar",
+				},
+			},
+		},
+	}, procs)
+}
+
 func TestGenerateHints(t *testing.T) {
 	tests := []struct {
 		annotations map[string]string
@@ -38,6 +62,7 @@ func TestGenerateHints(t *testing.T) {
 
 		// Scenarios being tested:
 		// logs/multiline.pattern must be a nested common.MapStr under hints.logs
+		// logs/processors.add_fields must be nested common.MapStr under hints.logs
 		// logs/json.keys_under_root must be a nested common.MapStr under hints.logs
 		// metrics/module must be found in hints.metrics
 		// not.to.include must not be part of hints
@@ -191,6 +216,6 @@ func TestGenerateHints(t *testing.T) {
 		for k, v := range test.annotations {
 			annMap.Put(k, v)
 		}
-		assert.Equal(t, GenerateHints(annMap, "foobar", "co.elastic"), test.result)
+		assert.Equal(t, test.result, GenerateHints(annMap, "foobar", "co.elastic"))
 	}
 }