daemon: expose prometheus in new global.monitoring config section + document it

refs #67

cmd/config_job_prometheus.go

@@ -12,6 +12,7 @@ import (
 )
 
 type PrometheusJob struct {
+	Name   string
 	Listen string
 }
 
@@ -55,12 +56,10 @@ func parsePrometheusJob(c JobParsingContext, name string, i map[string]interface
 	if s.Listen == "" {
 		return nil, errors.New("must specify 'listen' attribute")
 	}
-	return &PrometheusJob{s.Listen}, nil
+	return &PrometheusJob{name, s.Listen}, nil
 }
 
-func (*PrometheusJob) JobName() string {
-	return "prometheus"
-}
+func (j *PrometheusJob) JobName() string { return j.Name }
 
 func (j *PrometheusJob) JobType() JobType { return JobTypePrometheus }
 

cmd/config_parse.go

@@ -93,9 +93,30 @@ func parseConfig(i interface{}) (c *Config, err error) {
 
 	cpc := ConfigParsingContext{&c.Global}
 	jpc := JobParsingContext{cpc}
-
-	// Jobs
 	c.Jobs = make(map[string]Job, len(asMap.Jobs))
+
+	// FIXME internal jobs should not be mixed with user jobs
+	// Monitoring Jobs
+	var monJobs []map[string]interface{}
+	if err := mapstructure.Decode(asMap.Global["monitoring"], &monJobs); err != nil {
+		return nil, errors.Wrap(err, "cannot parse monitoring section")
+	}
+	for i, jc := range monJobs {
+		if jc["name"] == "" || jc["name"] == nil {
+			// FIXME internal jobs should not require a name...
+			jc["name"] = fmt.Sprintf("prometheus-%d", i)
+		}
+		job, err := parseJob(jpc, jc)
+		if err != nil {
+			return nil, errors.Wrapf(err, "cannot parse monitoring job #%d", i)
+		}
+		if job.JobType() != JobTypePrometheus {
+			return nil, errors.Errorf("monitoring job #%d has invalid job type", i)
+		}
+		c.Jobs[job.JobName()] = job
+	}
+
+	// Regular Jobs
 	for i := range asMap.Jobs {
 		job, err := parseJob(jpc, asMap.Jobs[i])
 		if err != nil {
@@ -109,7 +130,7 @@ func parseConfig(i interface{}) (c *Config, err error) {
 		}
 		jn := job.JobName()
 		if _, ok := c.Jobs[jn]; ok {
-			err = errors.Errorf("duplicate job name: %s", jn)
+			err = errors.Errorf("duplicate or invalid job name: %s", jn)
 			return nil, err
 		}
 		c.Jobs[job.JobName()] = job

cmd/config_test.go

@@ -17,7 +17,7 @@ func TestSampleConfigsAreParsedWithoutErrors(t *testing.T) {
 		"./sampleconf/pullbackup/backuphost.yml",
 		"./sampleconf/pullbackup/productionhost.yml",
 		"./sampleconf/random/debugging.yml",
-		"./sampleconf/random/logging.yml",
+		"./sampleconf/random/logging_and_monitoring.yml",
 	}
 
 	for _, p := range paths {

cmd/sampleconf/random/logging_and_monitoring.yml

@@ -20,5 +20,9 @@ global:
       level: debug
       format: logfmt
 
+  monitoring:
+
+    - type: prometheus
+      listen: ':9090'
 
 jobs: []