Added ctx passing to analyzer api call methods and moved semaphore su…

cmd/cardamon/main.go

@@ -45,9 +45,6 @@ func main() {
 		log.Fatalf("Failed to initialize Prometheus client: %v", err)
 	}
 	promAnalyzer := prom.NewAnalyzer(promClient)
-	if err != nil {
-		log.Fatalf("Failed to initialize Prometeheus analyzer: %v", err)
-	}
 	grafanaClient := grafana.NewClient(cfg.Grafana.Address, cfg.Grafana.PathPrefix, cfg.Grafana.Token, cfg.Grafana.Username, cfg.Grafana.Password)
 	grafanaAnalyzer := grafana.NewAnalyzer(grafanaClient)
 
@@ -58,7 +55,7 @@ func main() {
 		log.Fatalf("Error fetching all metric names from Prometheus: %v", err)
 	}
 
-	grafanaUsed, err := grafanaAnalyzer.DiscoverUsedMetrics()
+	grafanaUsed, err := grafanaAnalyzer.DiscoverUsedMetrics(ctx)
 	if err != nil {
 		fmt.Printf("Warning: Creawling Grafana failed: %v\n", err)
 	}

pkg/grafana/analyzer.go

@@ -15,6 +15,7 @@
 package grafana
 
 import (
+	"context"
 	"regexp"
 	"sync"
 )
@@ -32,8 +33,8 @@ func NewAnalyzer(client *Client) *Analyzer {
 }
 
 // DiscoverUsedMetrics crawls all dashboards and returns a unique set of metric names found.
-func (a *Analyzer) DiscoverUsedMetrics() ([]string, error) {
-	dashboards, err := a.client.SearchDashboards()
+func (a *Analyzer) DiscoverUsedMetrics(ctx context.Context) ([]string, error) {
+	dashboards, err := a.client.SearchDashboards(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -44,13 +45,14 @@ func (a *Analyzer) DiscoverUsedMetrics() ([]string, error) {
 	sem := make(chan struct{}, 10)
 
 	for _, dash := range dashboards {
+		// The Semaphore limits the amount of goroutines that can be created and thus also the API calls
+		sem <- struct{}{}
 		wg.Add(1)
 		go func(d DashboardMetadata) {
 			defer wg.Done()
-			sem <- struct{}{}
 			defer func() { <-sem }()
 
-			rawJSON, err := a.client.GetDashboardModel(d.UID)
+			rawJSON, err := a.client.GetDashboardModel(ctx, d.UID)
 			if err != nil {
 				return
 			}

pkg/grafana/client.go

@@ -15,6 +15,7 @@
 package grafana
 
 import (
+	"context"
 	"encoding/json"
 	"io"
 	"net/http"
@@ -48,8 +49,8 @@ func NewClient(url, pathPrefix string, token string, username string, password s
 }
 
 // newRequest is used to make a request to the Grafana instance, based on the params in the client struct.
-func (c *Client) newRequest(method, path string) (*http.Request, error) {
-	req, err := http.NewRequest(method, c.URL+c.PathPrefix+path, nil)
+func (c *Client) newRequest(ctx context.Context, method, path string) (*http.Request, error) {
+	req, err := http.NewRequestWithContext(ctx, method, c.URL+c.PathPrefix+path, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -63,8 +64,8 @@ func (c *Client) newRequest(method, path string) (*http.Request, error) {
 }
 
 // SearchDashboards finds all dashboard UIDs.
-func (c *Client) SearchDashboards() ([]DashboardMetadata, error) {
-	req, err := c.newRequest("GET", "/api/search?type=dash-db")
+func (c *Client) SearchDashboards(ctx context.Context) ([]DashboardMetadata, error) {
+	req, err := c.newRequest(ctx, "GET", "/api/search?type=dash-db")
 	if err != nil {
 		return nil, err
 	}
@@ -83,8 +84,8 @@ func (c *Client) SearchDashboards() ([]DashboardMetadata, error) {
 }
 
 // GetDashboardModel fetches the raw JSON of a dashboard based on a UID.
-func (c *Client) GetDashboardModel(uid string) ([]byte, error) {
-	req, err := c.newRequest("GET", "/api/dashboards/uid/"+uid)
+func (c *Client) GetDashboardModel(ctx context.Context, uid string) ([]byte, error) {
+	req, err := c.newRequest(ctx, "GET", "/api/dashboards/uid/"+uid)
 	if err != nil {
 		return nil, err
 	}