feat: run checks in parallel

closes #148

Signed-off-by: Clément Nussbaumer <clement.nussbaumer@postfinance.ch>

internal/servicecheck/servicecheck.go

@@ -9,6 +9,7 @@ import (
  "net"
  "net/http"
  "os"
+ "sync"
  "time"
 
  "github.com/prometheus/client_golang/prometheus"
@@ -70,41 +71,60 @@ func New(_ context.Context, cl client.Client, promRegistry *prometheus.Registry,
 // is respected.
 func (c *Checker) Run() {
  // Run Checks
- result := make(map[string]any)
+ result := sync.Map{}
+
+ wg := sync.WaitGroup{}
 
  // Cache result (used for /alive handler)
- defer func() { c.LastCheckResult = result }()
+ defer func() {
+ res := make(map[string]any)
+
+ result.Range(func(key, value any) bool {
+ k, _ := key.(string)
+ res[k] = value
+
+ return true
+ })
+
+ c.LastCheckResult = res
+ }()
+
+ wg.Add(4)
 
- c.measure(result, c.APIServerDirect, APIServerDirect)
- c.measure(result, c.APIServerDNS, APIServerDNS)
- c.measure(result, c.MeIngress, meIngress)
- c.measure(result, c.MeService, meService)
+ go c.measure(&wg, &result, c.APIServerDirect, APIServerDirect)
+ go c.measure(&wg, &result, c.APIServerDNS, APIServerDNS)
+ go c.measure(&wg, &result, c.MeIngress, meIngress)
+ go c.measure(&wg, &result, c.MeService, meService)
 
  if c.SkipCheckNeighbourhood {
- result[NeighbourhoodState] = skippedStr
+ result.Store(NeighbourhoodState, skippedStr)
  return
  }
 
  neighbours, err := c.getNeighbours(context.Background(), c.KubenurseNamespace, c.NeighbourFilter)
  if err != nil {
- result[NeighbourhoodState] = err.Error()
+ result.Store(NeighbourhoodState, err.Error())
  return
  }
 
- result[NeighbourhoodState] = okStr
- result[Neighbourhood] = neighbours
+ result.Store(NeighbourhoodState, okStr)
+ result.Store(Neighbourhood, neighbours)
 
  if c.NeighbourLimit > 0 && len(neighbours) > c.NeighbourLimit {
  neighbours = c.filterNeighbours(neighbours)
  }
 
+ wg.Add((len(neighbours)))
+
  for _, neighbour := range neighbours {
  check := func(ctx context.Context) string {
  return c.doRequest(ctx, podIPtoURL(neighbour.PodIP, c.UseTLS), true)
  }
 
- c.measure(result, check, "path_"+neighbour.NodeName)
+ go c.measure(&wg, &result, check, "path_"+neighbour.NodeName)
  }
+
+ wg.Wait()
 }
 
 // RunScheduled runs the checks in the specified interval which can be used to keep the metrics up-to-date. This
@@ -169,12 +189,13 @@ func (c *Checker) MeService(ctx context.Context) string {
 }
 
 // measure implements metric collections for the check
-func (c *Checker) measure(res map[string]any, check Check, requestType string) {
+func (c *Checker) measure(wg *sync.WaitGroup, res *sync.Map, check Check, requestType string) {
  // Add our label (check type) to the context so our http tracer can annotate
  // metrics and errors based with the label
- ctx := context.WithValue(context.Background(), kubenurseTypeKey{}, requestType)
+ defer wg.Done()
 
- res[requestType] = check(ctx)
+ ctx := context.WithValue(context.Background(), kubenurseTypeKey{}, requestType)
+ res.Store(requestType, check(ctx))
 }
 
 func podIPtoURL(podIP string, useTLS bool) string {