Avoid duplicate error printing

internal/metricAggregator/metricAggregator.go

@@ -94,8 +94,7 @@ func (c *metricAggregator) Init(output chan lp.CCMessage) error {
 	// Set hostname
 	hostname, err := os.Hostname()
 	if err != nil {
-		cclog.Error(err.Error())
-		return err
+		return fmt.Errorf("metricAggregator: failed to get hostname: %w", err)
 	}
 	// Drop domain part of host name
 	c.constants["hostname"] = strings.SplitN(hostname, `.`, 2)[0]

internal/metricRouter/metricCache.go

@@ -8,6 +8,7 @@
 package metricRouter
 
 import (
+	"fmt"
 	"sync"
 	"time"
 
@@ -70,8 +71,7 @@ func (c *metricCache) Init(output chan lp.CCMessage, ticker mct.MultiChanTicker,
 	// The code is executed by the MetricCache goroutine
 	c.aggEngine, err = agg.NewAggregator(c.output)
 	if err != nil {
-		cclog.ComponentError("MetricCache", "Cannot create aggregator")
-		return err
+		return fmt.Errorf("MetricCache: failed to create aggregator: %w", err)
 	}
 
 	return nil

internal/metricRouter/metricRouter.go

@@ -112,8 +112,7 @@ func (r *metricRouter) Init(ticker mct.MultiChanTicker, wg *sync.WaitGroup, rout
 	if r.config.NumCacheIntervals > 0 {
 		r.cache, err = NewCache(r.cache_input, r.ticker, &r.cachewg, r.config.NumCacheIntervals)
 		if err != nil {
-			cclog.ComponentError("MetricRouter", "MetricCache initialization failed:", err.Error())
-			return err
+			return fmt.Errorf("MetricRouter: failed to initialize MetricCache: %w", err)
 		}
 		for _, agg := range r.config.IntervalAgg {
 			err = r.cache.AddAggregation(agg.Name, agg.Function, agg.Condition, agg.Tags, agg.Meta)