roachprod: create type alias to hold NodeInfo map

Previously the NodeInfo to Node was stored in an ambiguous map
structure, leading to an improper printing of the ip ports stored in it,
this patch creates a type alias with a String() method to replace all
instances of this map structure.

Release note: none
Fixes: none
Informs: none

Author: Dev-Kyle

pkg/roachprod/promhelperclient/client.go

@@ -130,7 +130,7 @@ func (c *PromClient) setUrl(url string) {
 
 // instanceConfigRequest is the HTTP request received for generating instance config
 type instanceConfigRequest struct {
-	//Config is the content of the yaml file
+	// Config is the content of the yaml file
 	Config   string `json:"config"`
 	Insecure bool   `json:"insecure"`
 }
@@ -140,15 +140,15 @@ func (c *PromClient) UpdatePrometheusTargets(
 	ctx context.Context,
 	clusterName string,
 	forceFetchCreds bool,
-	nodes map[int][]*NodeInfo,
+	nodeTargets NodeTargets,
 	insecure bool,
 	l *logger.Logger,
 ) error {
 	if c.disabled {
 		l.Printf("Prometheus registration is disabled")
 		return nil
 	}
-	req, err := buildCreateRequest(nodes, insecure)
+	req, err := buildCreateRequest(nodeTargets, insecure)
 	if err != nil {
 		return err
 	}
@@ -171,7 +171,7 @@ func (c *PromClient) UpdatePrometheusTargets(
 		defer func() { _ = response.Body.Close() }()
 		if response.StatusCode == http.StatusUnauthorized && !forceFetchCreds {
 			l.Printf("request failed - this may be due to a stale token. retrying with forceFetchCreds true ...")
-			return c.UpdatePrometheusTargets(ctx, clusterName, true, nodes, insecure, l)
+			return c.UpdatePrometheusTargets(ctx, clusterName, true, nodeTargets, insecure, l)
 		}
 		body, err := io.ReadAll(response.Body)
 		if err != nil {
@@ -253,8 +253,23 @@ type NodeInfo struct {
 	CustomLabels map[string]string // Custom labels to be added to the cluster config
 }
 
+// NodeTargets contains prometheus scrape targets for each node.
+type NodeTargets map[int][]*NodeInfo
+
+func (nt NodeTargets) String() string {
+	var parts []string
+	for port, infos := range nt {
+		var targets []string
+		for _, info := range infos {
+			targets = append(targets, info.Target)
+		}
+		parts = append(parts, fmt.Sprintf("%d:[%s]", port, strings.Join(targets, ",")))
+	}
+	return strings.Join(parts, " ")
+}
+
 // createClusterConfigFile creates the cluster config file per node
-func buildCreateRequest(nodes map[int][]*NodeInfo, insecure bool) (io.Reader, error) {
+func buildCreateRequest(nodes NodeTargets, insecure bool) (io.Reader, error) {
 	configs := make([]*CCParams, 0)
 	for _, n := range nodes {
 		for _, node := range n {

pkg/roachprod/promhelperclient/client_test.go

@@ -46,12 +46,12 @@ func TestUpdatePrometheusTargets(t *testing.T) {
 			}, nil
 		}
 		err := c.UpdatePrometheusTargets(ctx, "c1", false,
-			map[int][]*NodeInfo{1: {{Target: "n1"}}}, true, l)
+			NodeTargets{1: {{Target: "n1"}}}, true, l)
 		require.NotNil(t, err)
 		require.Equal(t, fmt.Sprintf(ErrorMessage, 400, getUrl(promUrl, "c1"), "failed"), err.Error())
 	})
 	t.Run("UpdatePrometheusTargets succeeds", func(t *testing.T) {
-		nodeInfos := map[int][]*NodeInfo{
+		nodeInfos := NodeTargets{
 			1: {{
 				Target: "n1",
 			}},

pkg/roachprod/roachprod.go

@@ -818,7 +818,7 @@ func updatePrometheusTargets(
 	}
 
 	cl := promhelperclient.NewPromClient()
-	nodeIPPorts := make(map[int][]*promhelperclient.NodeInfo)
+	nodeIPPorts := promhelperclient.NodeTargets{}
 	nodeIPPortsMutex := syncutil.RWMutex{}
 	var wg sync.WaitGroup
 	for _, node := range c.Nodes {