Add documentation

internal/metricRouter/metricRouter.go

@@ -2,38 +2,42 @@ package metricRouter
 
 import (
 	"encoding/json"
-	cclog "github.com/ClusterCockpit/cc-metric-collector/internal/ccLogger"
 	"os"
 	"sync"
 	"time"
 
+	cclog "github.com/ClusterCockpit/cc-metric-collector/internal/ccLogger"
+
 	lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
 	mct "github.com/ClusterCockpit/cc-metric-collector/internal/multiChanTicker"
 	"gopkg.in/Knetic/govaluate.v2"
 )
 
+// Metric router tag configuration
 type metricRouterTagConfig struct {
-	Key       string `json:"key"`
-	Value     string `json:"value"`
-	Condition string `json:"if"`
+	Key       string `json:"key"`   // Tag name
+	Value     string `json:"value"` // Tag value
+	Condition string `json:"if"`    // Condition for adding or removing corresponding tag
 }
 
+// Metric router configuration
 type metricRouterConfig struct {
-	AddTags       []metricRouterTagConfig `json:"add_tags"`
-	DelTags       []metricRouterTagConfig `json:"delete_tags"`
-	IntervalStamp bool                    `json:"interval_timestamp"`
+	AddTags       []metricRouterTagConfig `json:"add_tags"`           // List of tags that are added when the condition is met
+	DelTags       []metricRouterTagConfig `json:"delete_tags"`        // List of tags that are removed when the condition is met
+	IntervalStamp bool                    `json:"interval_timestamp"` // Update timestamp periodically?
 }
 
 type metricRouter struct {
-	inputs    []chan lp.CCMetric
-	outputs   []chan lp.CCMetric
-	done      chan bool
+	inputs    []chan lp.CCMetric // List of all input channels
+	outputs   []chan lp.CCMetric // List of all output channels
+	done      chan bool          // channel to finish stop metric router
 	wg        *sync.WaitGroup
-	timestamp time.Time
+	timestamp time.Time // timestamp
 	ticker    mct.MultiChanTicker
 	config    metricRouterConfig
 }
 
+// MetricRouter access functions
 type MetricRouter interface {
 	Init(ticker mct.MultiChanTicker, wg *sync.WaitGroup, routerConfigFile string) error
 	AddInput(input chan lp.CCMetric)
@@ -42,6 +46,12 @@ type MetricRouter interface {
 	Close()
 }
 
+// Init initializes a metric router by setting up:
+// * input and output channels
+// * done channel
+// * wait group synchronization (from variable wg)
+// * ticker (from variable ticker)
+// * configuration (read from config file in variable routerConfigFile)
 func (r *metricRouter) Init(ticker mct.MultiChanTicker, wg *sync.WaitGroup, routerConfigFile string) error {
 	r.inputs = make([]chan lp.CCMetric, 0)
 	r.outputs = make([]chan lp.CCMetric, 0)
@@ -63,25 +73,27 @@ func (r *metricRouter) Init(ticker mct.MultiChanTicker, wg *sync.WaitGroup, rout
 	return nil
 }
 
+// StartTimer starts a timer which updates timestamp periodically
 func (r *metricRouter) StartTimer() {
 	m := make(chan time.Time)
 	r.ticker.AddChannel(m)
 	go func() {
 		for {
-			select {
-			case t := <-m:
-				r.timestamp = t
-			}
+			t := <-m
+			r.timestamp = t
 		}
 	}()
 }
 
+// EvalCondition evaluates condition Cond for metric data from point
 func (r *metricRouter) EvalCondition(Cond string, point lp.CCMetric) (bool, error) {
 	expression, err := govaluate.NewEvaluableExpression(Cond)
 	if err != nil {
 		cclog.ComponentDebug("MetricRouter", Cond, " = ", err.Error())
 		return false, err
 	}
+
+	// Add metric name, tags, meta data, fields and timestamp to the parameter list
 	params := make(map[string]interface{})
 	params["name"] = point.Name()
 	for _, t := range point.TagList() {
@@ -95,6 +107,7 @@ func (r *metricRouter) EvalCondition(Cond string, point lp.CCMetric) (bool, erro
 	}
 	params["timestamp"] = point.Time()
 
+	// evaluate condition
 	result, err := expression.Evaluate(params)
 	if err != nil {
 		cclog.ComponentDebug("MetricRouter", Cond, " = ", err.Error())
@@ -103,6 +116,7 @@ func (r *metricRouter) EvalCondition(Cond string, point lp.CCMetric) (bool, erro
 	return bool(result.(bool)), err
 }
 
+// DoAddTags adds a tag when condition is fullfiled
 func (r *metricRouter) DoAddTags(point lp.CCMetric) {
 	for _, m := range r.config.AddTags {
 		var conditionMatches bool
@@ -123,6 +137,7 @@ func (r *metricRouter) DoAddTags(point lp.CCMetric) {
 	}
 }
 
+// DoDelTags removes a tag when condition is fullfiled
 func (r *metricRouter) DoDelTags(point lp.CCMetric) {
 	for _, m := range r.config.DelTags {
 		var conditionMatches bool
@@ -143,6 +158,7 @@ func (r *metricRouter) DoDelTags(point lp.CCMetric) {
 	}
 }
 
+// Start starts the metric router
 func (r *metricRouter) Start() {
 	r.wg.Add(1)
 	r.timestamp = time.Now()