Ensure that job names are unique in parsed configs.

Change-Id: I6bd89e6401bd924315981db797af21bdf0b81252

config/config.go

@@ -69,7 +69,13 @@ func (c Config) Validate() error {
 	}
 
 	// Check each job configuration for validity.
+	jobNames := map[string]bool{}
 	for _, job := range c.Job {
+		if jobNames[job.GetName()] {
+			return fmt.Errorf("Found multiple jobs configured with the same name: '%s'", job.GetName())
+		}
+		jobNames[job.GetName()] = true
+
 		if !jobNameRE.MatchString(job.GetName()) {
 			return fmt.Errorf("Invalid job name '%s'", job.GetName())
 		}

config/config_test.go

@@ -60,6 +60,11 @@ var configTests = []struct {
 		shouldFail:  true,
 		errContains: "Specified both DNS-SD name and target group",
 	},
+	{
+		inputFile:   "repeated_job_name.conf.input",
+		shouldFail:  true,
+		errContains: "Found multiple jobs configured with the same name: 'testjob1'",
+	},
 }
 
 func TestConfigs(t *testing.T) {

config/fixtures/repeated_job_name.conf.input

@@ -0,0 +1,11 @@
+job: <
+  name: "testjob1"
+>
+
+job: <
+  name: "testjob2"
+>
+
+job: <
+  name: "testjob1"
+>