Add a config to decode json-encoded strings in attribute values (#2827)

* decoding json-encoded attribute values

* update config unit tests

* cover exception cases

Author: pxaws

exporter/awsemfexporter/README.md

@@ -25,6 +25,7 @@ The following exporter configuration parameters are supported.
 | `max_retries`     | Maximum number of retries before abandoning an attempt to post data.   |    1    |
 | `dimension_rollup_option`| DimensionRollupOption is the option for metrics dimension rollup. Three options are available. |"ZeroAndSingleDimensionRollup" (Enable both zero dimension rollup and single dimension rollup)| 
 | `resource_to_telemetry_conversion` | "resource_to_telemetry_conversion" is the option for converting resource attributes to telemetry attributes. It has only one config onption- `enabled`. For metrics, if `enabled=true`, all the resource attributes will be converted to metric labels by default. See `Resource Attributes to Metric Labels` section below for examples. | `enabled=false` | 
+| `parse_json_encoded_attr_values` | List of attribute keys whose corresponding values are JSON-encoded strings and will be converted to  JSON structures in emf logs. For example, the attribute string value "{\\"x\\":5,\\"y\\":6}" will be converted to a json object: ```{"x": 5, "y": 6}```| [ ] | 
 | [`metric_declarations`](#metric_declaration) | List of rules for filtering exported metrics and their dimensions. |    [ ]   |
 | [`metric_descriptors`](#metric_descriptor) | List of rules for inserting or updating metric descriptors.| [ ]|
 

exporter/awsemfexporter/config.go

@@ -61,6 +61,10 @@ type Config struct {
 	// "SingleDimensionRollupOnly" - Enable single dimension rollup
 	// "NoDimensionRollup" - No dimension rollup (only keep original metrics which contain all dimensions)
 	DimensionRollupOption string `mapstructure:"dimension_rollup_option"`
+	// ParseJSONEncodedAttributeValues is an array of attribute keys whose corresponding values are JSON-encoded as strings.
+	// Those strings will be decoded to its original json structure.
+	ParseJSONEncodedAttributeValues []string `mapstructure:"parse_json_encoded_attr_values"`
+
 	// MetricDeclarations is the list of rules to be used to set dimensions for exported metrics.
 	MetricDeclarations []*MetricDeclaration `mapstructure:"metric_declarations"`
 

exporter/awsemfexporter/config_test.go

@@ -49,39 +49,41 @@ func TestLoadConfig(t *testing.T) {
 	r1.Validate()
 	assert.Equal(t,
 		&Config{
-			ExporterSettings:      configmodels.ExporterSettings{TypeVal: configmodels.Type(typeStr), NameVal: "awsemf/1"},
-			LogGroupName:          "",
-			LogStreamName:         "",
-			Endpoint:              "",
-			RequestTimeoutSeconds: 30,
-			MaxRetries:            1,
-			NoVerifySSL:           false,
-			ProxyAddress:          "",
-			Region:                "us-west-2",
-			RoleARN:               "arn:aws:iam::123456789:role/monitoring-EKS-NodeInstanceRole",
-			DimensionRollupOption: "ZeroAndSingleDimensionRollup",
-			MetricDeclarations:    []*MetricDeclaration{},
-			MetricDescriptors:     []MetricDescriptor{},
+			ExporterSettings:                configmodels.ExporterSettings{TypeVal: configmodels.Type(typeStr), NameVal: "awsemf/1"},
+			LogGroupName:                    "",
+			LogStreamName:                   "",
+			Endpoint:                        "",
+			RequestTimeoutSeconds:           30,
+			MaxRetries:                      1,
+			NoVerifySSL:                     false,
+			ProxyAddress:                    "",
+			Region:                          "us-west-2",
+			RoleARN:                         "arn:aws:iam::123456789:role/monitoring-EKS-NodeInstanceRole",
+			DimensionRollupOption:           "ZeroAndSingleDimensionRollup",
+			ParseJSONEncodedAttributeValues: make([]string, 0),
+			MetricDeclarations:              []*MetricDeclaration{},
+			MetricDescriptors:               []MetricDescriptor{},
 		}, r1)
 
 	r2 := cfg.Exporters["awsemf/resource_attr_to_label"].(*Config)
 	r2.Validate()
 	assert.Equal(t, r2,
 		&Config{
-			ExporterSettings:            configmodels.ExporterSettings{TypeVal: configmodels.Type(typeStr), NameVal: "awsemf/resource_attr_to_label"},
-			LogGroupName:                "",
-			LogStreamName:               "",
-			Endpoint:                    "",
-			RequestTimeoutSeconds:       30,
-			MaxRetries:                  1,
-			NoVerifySSL:                 false,
-			ProxyAddress:                "",
-			Region:                      "",
-			RoleARN:                     "",
-			DimensionRollupOption:       "ZeroAndSingleDimensionRollup",
-			ResourceToTelemetrySettings: exporterhelper.ResourceToTelemetrySettings{Enabled: true},
-			MetricDeclarations:          []*MetricDeclaration{},
-			MetricDescriptors:           []MetricDescriptor{},
+			ExporterSettings:                configmodels.ExporterSettings{TypeVal: configmodels.Type(typeStr), NameVal: "awsemf/resource_attr_to_label"},
+			LogGroupName:                    "",
+			LogStreamName:                   "",
+			Endpoint:                        "",
+			RequestTimeoutSeconds:           30,
+			MaxRetries:                      1,
+			NoVerifySSL:                     false,
+			ProxyAddress:                    "",
+			Region:                          "",
+			RoleARN:                         "",
+			DimensionRollupOption:           "ZeroAndSingleDimensionRollup",
+			ResourceToTelemetrySettings:     exporterhelper.ResourceToTelemetrySettings{Enabled: true},
+			ParseJSONEncodedAttributeValues: make([]string, 0),
+			MetricDeclarations:              []*MetricDeclaration{},
+			MetricDescriptors:               []MetricDescriptor{},
 		})
 }
 

exporter/awsemfexporter/emf_exporter.go

@@ -127,7 +127,7 @@ func (emf *emfExporter) pushMetricsData(_ context.Context, md pdata.Metrics) err
 
 	for _, groupedMetric := range groupedMetrics {
 		cWMetric := translateGroupedMetricToCWMetric(groupedMetric, expConfig)
-		putLogEvent := translateCWMetricToEMF(cWMetric)
+		putLogEvent := translateCWMetricToEMF(cWMetric, expConfig)
 
 		logGroup := groupedMetric.Metadata.LogGroup
 		logStream := groupedMetric.Metadata.LogStream

exporter/awsemfexporter/factory.go

@@ -42,19 +42,20 @@ func createDefaultConfig() configmodels.Exporter {
 			TypeVal: configmodels.Type(typeStr),
 			NameVal: typeStr,
 		},
-		LogGroupName:          "",
-		LogStreamName:         "",
-		Namespace:             "",
-		Endpoint:              "",
-		RequestTimeoutSeconds: 30,
-		MaxRetries:            1,
-		NoVerifySSL:           false,
-		ProxyAddress:          "",
-		Region:                "",
-		RoleARN:               "",
-		DimensionRollupOption: "ZeroAndSingleDimensionRollup",
-		MetricDeclarations:    make([]*MetricDeclaration, 0),
-		logger:                nil,
+		LogGroupName:                    "",
+		LogStreamName:                   "",
+		Namespace:                       "",
+		Endpoint:                        "",
+		RequestTimeoutSeconds:           30,
+		MaxRetries:                      1,
+		NoVerifySSL:                     false,
+		ProxyAddress:                    "",
+		Region:                          "",
+		RoleARN:                         "",
+		DimensionRollupOption:           "ZeroAndSingleDimensionRollup",
+		ParseJSONEncodedAttributeValues: make([]string, 0),
+		MetricDeclarations:              make([]*MetricDeclaration, 0),
+		logger:                          nil,
 	}
 }
 

exporter/awsemfexporter/metric_translator.go

@@ -17,6 +17,7 @@ package awsemfexporter
 import (
 	"encoding/json"
 	"fmt"
+	"reflect"
 	"time"
 
 	"go.opentelemetry.io/collector/consumer/pdata"
@@ -332,11 +333,39 @@ func groupedMetricToCWMeasurementsWithFilters(groupedMetric *GroupedMetric, conf
 }
 
 // translateCWMetricToEMF converts CloudWatch Metric format to EMF.
-func translateCWMetricToEMF(cWMetric *CWMetrics) *LogEvent {
+func translateCWMetricToEMF(cWMetric *CWMetrics, config *Config) *LogEvent {
 	// convert CWMetric into map format for compatible with PLE input
 	cWMetricMap := make(map[string]interface{})
 	fieldMap := cWMetric.Fields
 
+	//restore the json objects that are stored as string in attributes
+	for _, key := range config.ParseJSONEncodedAttributeValues {
+		if fieldMap[key] == nil {
+			continue
+		}
+
+		if val, ok := fieldMap[key].(string); ok {
+			var f interface{}
+			err := json.Unmarshal([]byte(val), &f)
+			if err != nil {
+				config.logger.Debug(
+					"Failed to parse json-encoded string",
+					zap.String("label key", key),
+					zap.String("label value", val),
+					zap.Error(err),
+				)
+				continue
+			}
+			fieldMap[key] = f
+		} else {
+			config.logger.Debug(
+				"Invalid json-encoded data. A string is expected",
+				zap.Any("type", reflect.TypeOf(fieldMap[key])),
+				zap.Any("value", reflect.ValueOf(fieldMap[key])),
+			)
+		}
+	}
+
 	// Create `_aws` section only if there are measurements
 	if len(cWMetric.Measurements) > 0 {
 		// Create `_aws` section only if there are measurements

exporter/awsemfexporter/metric_translator_test.go

@@ -535,13 +535,22 @@ func TestTranslateCWMetricToEMF(t *testing.T) {
 	fields[oTellibDimensionKey] = "cloudwatch-otel"
 	fields["spanName"] = "test"
 	fields["spanCounter"] = 0
+	//add stringified json as attribute values
+	fields["kubernetes"] = "{\"container_name\":\"cloudwatch-agent\",\"docker\":{\"container_id\":\"fc1b0a4c3faaa1808e187486a3a90cbea883dccaf2e2c46d4069d663b032a1ca\"},\"host\":\"ip-192-168-58-245.ec2.internal\",\"labels\":{\"controller-revision-hash\":\"5bdbf497dc\",\"name\":\"cloudwatch-agent\",\"pod-template-generation\":\"1\"},\"namespace_name\":\"amazon-cloudwatch\",\"pod_id\":\"e23f3413-af2e-4a98-89e0-5df2251e7f05\",\"pod_name\":\"cloudwatch-agent-26bl6\",\"pod_owners\":[{\"owner_kind\":\"DaemonSet\",\"owner_name\":\"cloudwatch-agent\"}]}"
+	fields["Sources"] = "[\"cadvisor\",\"pod\",\"calculated\"]"
+
+	config := &Config{
+		//include valid json string, a non-existing key, and keys whose value are not json/string
+		ParseJSONEncodedAttributeValues: []string{"kubernetes", "Sources", "NonExistingAttributeKey", "spanName", "spanCounter"},
+		logger:                          zap.NewNop(),
+	}
 
 	met := &CWMetrics{
 		TimestampMs:  timestamp,
 		Fields:       fields,
 		Measurements: []CWMeasurement{cwMeasurement},
 	}
-	inputLogEvent := translateCWMetricToEMF(met)
+	inputLogEvent := translateCWMetricToEMF(met, config)
 
 	assert.Equal(t, readFromFile("testdata/testTranslateCWMetricToEMF.json"), *inputLogEvent.InputLogEvent.Message, "Expect to be equal")
 }
@@ -1994,7 +2003,7 @@ func TestTranslateCWMetricToEMFNoMeasurements(t *testing.T) {
 		Fields:       fields,
 		Measurements: nil,
 	}
-	inputLogEvent := translateCWMetricToEMF(met)
+	inputLogEvent := translateCWMetricToEMF(met, &Config{})
 	expected := "{\"OTelLib\":\"cloudwatch-otel\",\"spanCounter\":0,\"spanName\":\"test\"}"
 
 	assert.Equal(t, expected, *inputLogEvent.InputLogEvent.Message)
@@ -2132,6 +2141,6 @@ func BenchmarkTranslateCWMetricToEMF(b *testing.B) {
 
 	b.ResetTimer()
 	for n := 0; n < b.N; n++ {
-		translateCWMetricToEMF(met)
+		translateCWMetricToEMF(met, &Config{})
 	}
 }

exporter/awsemfexporter/testdata/testTranslateCWMetricToEMF.json

@@ -1 +1 @@
-{"OTelLib":"cloudwatch-otel","_aws":{"CloudWatchMetrics":[{"Namespace":"test-emf","Dimensions":[["OTelLib"],["OTelLib","spanName"]],"Metrics":[{"Name":"spanCounter","Unit":"Count"}]}],"Timestamp":1596151098037},"spanCounter":0,"spanName":"test"}
+{"OTelLib":"cloudwatch-otel","Sources":["cadvisor","pod","calculated"],"_aws":{"CloudWatchMetrics":[{"Namespace":"test-emf","Dimensions":[["OTelLib"],["OTelLib","spanName"]],"Metrics":[{"Name":"spanCounter","Unit":"Count"}]}],"Timestamp":1596151098037},"kubernetes":{"container_name":"cloudwatch-agent","docker":{"container_id":"fc1b0a4c3faaa1808e187486a3a90cbea883dccaf2e2c46d4069d663b032a1ca"},"host":"ip-192-168-58-245.ec2.internal","labels":{"controller-revision-hash":"5bdbf497dc","name":"cloudwatch-agent","pod-template-generation":"1"},"namespace_name":"amazon-cloudwatch","pod_id":"e23f3413-af2e-4a98-89e0-5df2251e7f05","pod_name":"cloudwatch-agent-26bl6","pod_owners":[{"owner_kind":"DaemonSet","owner_name":"cloudwatch-agent"}]},"spanCounter":0,"spanName":"test"}