remove older porter agent and check for monitoring node when installing new porter agent

api/server/handlers/cluster/install_agent.go

@@ -1,6 +1,7 @@
 package cluster
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 
@@ -13,7 +14,14 @@ import (
 	"github.com/porter-dev/porter/internal/auth/token"
 	"github.com/porter-dev/porter/internal/helm"
 	"github.com/porter-dev/porter/internal/helm/loader"
+	"github.com/porter-dev/porter/internal/kubernetes"
 	"github.com/porter-dev/porter/internal/models"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+const (
+	monitoringNodeLabel = "porter.run/workload-kind=monitoring"
+	olderAgentLabel     = "control-plane=controller-manager"
 )
 
 type InstallAgentHandler struct {
@@ -36,6 +44,21 @@ func (c *InstallAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request)
 	proj, _ := r.Context().Value(types.ProjectScope).(*models.Project)
 	user, _ := r.Context().Value(types.UserScope).(*models.User)
 	cluster, _ := r.Context().Value(types.ClusterScope).(*models.Cluster)
+
+	k8sAgent, err := c.GetAgent(r, cluster, "porter-agent-system")
+
+	if err != nil {
+		c.HandleAPIError(w, r, apierrors.NewErrInternal(err))
+		return
+	}
+
+	err = checkAndDeleteOlderAgent(k8sAgent)
+
+	if err != nil {
+		c.HandleAPIError(w, r, apierrors.NewErrInternal(err))
+		return
+	}
+
 	helmAgent, err := c.GetHelmAgent(r, cluster, "porter-agent-system")
 
 	if err != nil {
@@ -87,6 +110,13 @@ func (c *InstallAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request)
 		},
 	}
 
+	if exists, err := checkIfMonitoringNodeExists(k8sAgent); err != nil {
+		c.HandleAPIError(w, r, apierrors.NewErrInternal(err))
+		return
+	} else if exists {
+		porterAgentValues["monitoringWorkload"] = true
+	}
+
 	conf := &helm.InstallChartConfig{
 		Chart:     chart,
 		Name:      "porter-agent",
@@ -100,8 +130,7 @@ func (c *InstallAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request)
 
 	if err != nil {
 		c.HandleAPIError(w, r, apierrors.NewErrPassThroughToClient(
-			fmt.Errorf("error installing a new chart: %s", err.Error()),
-			http.StatusBadRequest,
+			fmt.Errorf("error installing porter-agent: %w", err), http.StatusBadRequest,
 		))
 
 		return
@@ -109,3 +138,61 @@ func (c *InstallAgentHandler) ServeHTTP(w http.ResponseWriter, r *http.Request)
 
 	w.WriteHeader(http.StatusOK)
 }
+
+func checkAndDeleteOlderAgent(k8sAgent *kubernetes.Agent) error {
+	namespaceList, err := k8sAgent.Clientset.CoreV1().Namespaces().List(context.Background(), v1.ListOptions{})
+
+	if err != nil {
+		return fmt.Errorf("error listing namespaces: %w", err)
+	}
+
+	nsExists := false
+
+	for _, namespace := range namespaceList.Items {
+		if namespace.Name == "porter-agent-system" {
+			nsExists = true
+			break
+		}
+	}
+
+	if !nsExists {
+		return nil
+	}
+
+	podList, err := k8sAgent.Clientset.CoreV1().Pods("porter-agent-system").List(context.Background(), v1.ListOptions{
+		LabelSelector: olderAgentLabel,
+	})
+
+	if err != nil {
+		return fmt.Errorf("error listing pods for older porter-agent: %w", err)
+	}
+
+	if len(podList.Items) > 0 {
+		// older porter-agent exists, delete the entire namespace
+		err := k8sAgent.Clientset.CoreV1().Namespaces().Delete(
+			context.Background(), "porter-agent-system", v1.DeleteOptions{},
+		)
+
+		if err != nil {
+			return fmt.Errorf("error deleting older porter-agent's namespace: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func checkIfMonitoringNodeExists(k8sAgent *kubernetes.Agent) (bool, error) {
+	nodeList, err := k8sAgent.Clientset.CoreV1().Nodes().List(context.Background(), v1.ListOptions{
+		LabelSelector: monitoringNodeLabel,
+	})
+
+	if err != nil {
+		return false, fmt.Errorf("error listing nodes: %w", err)
+	}
+
+	if len(nodeList.Items) > 0 {
+		return true, nil
+	}
+
+	return false, nil
+}