feat: add support to default alias in producers/consumers configuration

kafka-config.yml.sample

@@ -165,8 +165,8 @@ integrations:
     # In order to collect Java producer and consumer metrics the "producers" and "consumers" fields should be filled out.
     # Both fields are JSON arrays with each entry being a separate JAVA producer or consumer, in it's respective field.
     # Each entry should have the following fields:
-    # - name: This is the client.id of the producer/consumer as it appears in Kafka.
-    # - host: The IP or Hostname of the producer/consumser. If omitted, will use the value of the "default_jmx_host" field
+    # - name: This is the client.id of the producer/consumer as it appears in Kafka. If omitted, metrics from all clients in the JMX host:port will be reported.
+    # - host: The IP or Hostname of the producer/consumer. If omitted, will use the value of the "default_jmx_host" field
     # - port: The port in which JMX is setup for on the producer/consumer. If omitted will, use the value of the "default_jmx_port" field
     # - username: The username used to connect to JMX. If omitted, will use the value of the "default_jmx_user" field
     # - password: The password used to connect to JMX. If omitted, will use the value of the "default_jmx_password" field
@@ -175,7 +175,10 @@ integrations:
     CONSUMERS: '[{"name": "myConsumer", "host": "localhost", "port": 24, "username": "me", "password": "secret"}]'
     # If several producers/consumers are on the same host an agent can be installed on that host and the
     # "default_jmx_host" and "default_jmx_port" field can be set once and used for all producers/consumers that
-    # do not have the "host" or "port" field repsectively.
+    # do not have the "host" or "port" field respectively.
+    # When defaults are set it is also possible to use the string "default" to gather metrics from all producers /
+    # consumers in the "default_jmx_host:default_jmx_port". Example:
+    # PRODUCERS: default
     # These fields can be removed if each producer/consumer has it's own "host" and/or "port" field filled out.
     DEFAULT_JMX_HOST: "localhost"
     DEFAULT_JMX_PORT: "9999"

src/args/args_test.go

@@ -9,6 +9,7 @@ import (
 	sdkArgs "github.com/newrelic/infra-integrations-sdk/args"
 	"github.com/newrelic/infra-integrations-sdk/integration"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestParseArgs(t *testing.T) {
@@ -217,3 +218,93 @@ func Test_unmarshalConsumerGroups_NoTopics(t *testing.T) {
 		t.Error("Expected error")
 	}
 }
+
+func TestUnMarshalJMXHosts(t *testing.T) {
+	arguments := &ArgumentList{
+		DefaultJMXUser:     "user",
+		DefaultJMXPassword: "password",
+		DefaultJMXPort:     42,
+		DefaultJMXHost:     "host",
+	}
+	cases := []struct {
+		Name     string
+		Input    string
+		Expected []*JMXHost
+	}{
+		{
+			Name:     "Empty",
+			Input:    `[]`,
+			Expected: []*JMXHost{},
+		},
+		{
+			Name:  "Default with no alias",
+			Input: `[{}]`,
+			Expected: []*JMXHost{
+				{
+					User:     arguments.DefaultJMXUser,
+					Password: arguments.DefaultJMXPassword,
+					Port:     arguments.DefaultJMXPort,
+					Host:     arguments.DefaultJMXHost,
+				},
+			},
+		},
+		{
+			Name:  "Default with alias",
+			Input: `default`,
+			Expected: []*JMXHost{
+				{
+					User:     arguments.DefaultJMXUser,
+					Password: arguments.DefaultJMXPassword,
+					Port:     arguments.DefaultJMXPort,
+					Host:     arguments.DefaultJMXHost,
+				},
+			},
+		},
+		{
+			Name:  "Only name set",
+			Input: `[{"name": "client.id"}]`,
+			Expected: []*JMXHost{
+				{
+					Name:     "client.id",
+					User:     arguments.DefaultJMXUser,
+					Password: arguments.DefaultJMXPassword,
+					Port:     arguments.DefaultJMXPort,
+					Host:     arguments.DefaultJMXHost,
+				},
+			},
+		},
+		{
+			Name:  "No name set",
+			Input: `[{"user": "my.user", "password": "my.pass", "port": 1088, "host": "localhost"}]`,
+			Expected: []*JMXHost{
+				{
+					User:     "my.user",
+					Password: "my.pass",
+					Port:     1088,
+					Host:     "localhost",
+				},
+			},
+		},
+		{
+			Name:  "All values set",
+			Input: `[{"name": "my.name", "user": "my.user", "password": "my.pass", "port": 1088, "host": "localhost"}]`,
+			Expected: []*JMXHost{
+				{
+					Name:     "my.name",
+					User:     "my.user",
+					Password: "my.pass",
+					Port:     1088,
+					Host:     "localhost",
+				},
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Name, func(t *testing.T) {
+			parsed, err := unmarshalJMXHosts([]byte(c.Input), arguments)
+			require.NoError(t, err)
+			require.Equal(t, c.Expected, parsed)
+		})
+	}
+}

src/args/parsed_args.go

@@ -19,6 +19,8 @@ var GlobalArgs *ParsedArguments
 const (
 	defaultZookeeperPort = 2181
 	defaultJMXPort       = 9999
+
+	jmxHostDefaultAlias = "default"
 )
 
 // ParsedArguments is an special version of the config arguments that has advanced parsing
@@ -313,10 +315,11 @@ func ParseArgs(a ArgumentList) (*ParsedArguments, error) {
 // unmarshalJMXHosts parses the user-provided JSON map for a producer
 // or consumers into a jmxHost structs and sets default values
 func unmarshalJMXHosts(data []byte, a *ArgumentList) ([]*JMXHost, error) {
-
 	// Parse the producer or consumer
 	var v []*JMXHost
-	if err := json.Unmarshal([]byte(data), &v); err != nil {
+	if string(data) == jmxHostDefaultAlias {
+		v = []*JMXHost{{}}
+	} else if err := json.Unmarshal(data, &v); err != nil {
 		return nil, err
 	}