Use channels, add a metric router, split up configuration and use extended version of Influx line protocol internally

internal/metricRouter/metricRouter.go

@@ -0,0 +1,118 @@
+package metricRouter
+
+import (
+    lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
+    "sync"
+    "log"
+    "encoding/json"
+    "os"
+)
+
+type metricRounterTagConfig struct {
+    Key string `json:"key"`
+    Value string `json:"value"`
+    Condition string `json:"if"`
+}
+
+type metricRouterConfig struct {
+    AddTags []metricRounterTagConfig `json:"add_tags"`
+    DelTags []metricRounterTagConfig `json:"delete_tags"`
+    IntervalStamp bool `json:"interval_timestamp"`
+}
+
+type metricRouter struct {
+	inputs     []chan lp.CCMetric
+	outputs     []chan lp.CCMetric
+	done        chan bool
+	wg          *sync.WaitGroup
+	config      metricRouterConfig
+}
+
+type MetricRouter interface {
+	Init(routerDone chan bool, wg *sync.WaitGroup) error
+	AddInput(input chan lp.CCMetric)
+	AddOutput(output chan lp.CCMetric)
+	ReadConfig(filename string) error
+	Start()
+	Close()
+}
+
+
+func (r *metricRouter) Init(routerDone chan bool, wg *sync.WaitGroup) error {
+    r.inputs = make([]chan lp.CCMetric, 0)
+    r.outputs = make([]chan lp.CCMetric, 0)
+    r.done = routerDone
+    r.wg = wg
+    return nil
+}
+
+func (r *metricRouter) ReadConfig(filename string) error {
+    configFile, err := os.Open(filename)
+    if err != nil {
+        log.Print(err.Error())
+        return err
+    }
+    defer configFile.Close()
+    jsonParser := json.NewDecoder(configFile)
+	err = jsonParser.Decode(&r.config)
+	if err != nil {
+	    log.Print(err.Error())
+        return err
+    }
+    return nil
+}
+
+func (r *metricRouter) Start() {
+    r.wg.Add(1)
+    go func() {
+        for {
+RouterLoop:
+            select {
+            case <- r.done:
+                log.Print("[MetricRouter] DONE\n")
+                r.wg.Done()
+                break RouterLoop
+            default:
+                for _, c := range r.inputs {
+RouterInputLoop:
+                    select {
+                    case <- r.done:
+                        log.Print("[MetricRouter] DONE\n")
+                        r.wg.Done()
+                        break RouterInputLoop
+                    case p := <- c:
+                        log.Print("[MetricRouter] FORWARD ",p)
+                        for _, o := range r.outputs {
+                            o <- p
+                        }
+                    default:
+                    }
+                }
+            }
+        }
+        log.Print("[MetricRouter] EXIT\n")
+    }()
+    log.Print("[MetricRouter] STARTED\n")
+}
+
+func (r *metricRouter) AddInput(input chan lp.CCMetric) {
+    r.inputs = append(r.inputs, input)
+}
+
+func (r *metricRouter) AddOutput(output chan lp.CCMetric) {
+    r.outputs = append(r.outputs, output)
+}
+
+func (r *metricRouter) Close() {
+    r.done <- true
+    log.Print("[MetricRouter] CLOSE\n")
+}
+
+func New(done chan bool, wg *sync.WaitGroup) (MetricRouter, error) {
+    r := &metricRouter{}
+    err := r.Init(done, wg)
+    if err != nil {
+        return nil, err
+    }
+    return r, err
+}