fix(gke): Update collect method to gracefully fail

There is a condition where a failure to find a machine type in the price
map was causing the `Collect` method to return instead of continuing.
Instead, this changes the logic to log out the message within `Collect`
and continue operating.
Adds a unit test to reproduce the error and then validates it is
resolved.

A future improvement here would be to
1. Export a metric
2. Set a sane default value(if provided?)

- closes #335

pkg/google/gke/gke.go

@@ -145,6 +145,13 @@ func (c *Collector) Collect(ch chan<- prometheus.Metric) error {
 				clusterName := instance.GetClusterName()
 				// We skip instances that do not have a clusterName because they are not associated with an GKE cluster
 				if clusterName == "" {
+					c.logger.LogAttrs(ctx,
+						slog.LevelDebug,
+						"instance does not have a clustername",
+						slog.String("region", instance.Region),
+						slog.String("machine_type", instance.MachineType),
+						slog.String("project", project),
+					)
 					continue
 				}
 				labelValues := []string{
@@ -158,7 +165,16 @@ func (c *Collector) Collect(ch chan<- prometheus.Metric) error {
 				}
 				cpuCost, ramCost, err := c.PricingMap.GetCostOfInstance(instance)
 				if err != nil {
-					return err
+					// Log out the error and continue processing nodes
+					// TODO(@pokom): Should we set sane defaults here to emit _something_?
+					c.logger.LogAttrs(ctx,
+						slog.LevelError,
+						err.Error(),
+						slog.String("machine_type", instance.MachineType),
+						slog.String("region", instance.Region),
+						slog.String("project", project),
+					)
+					continue
 				}
 				ch <- prometheus.MustNewConstMetric(
 					gkeNodeCPUHourlyCostDesc,
@@ -198,6 +214,16 @@ func (c *Collector) Collect(ch chan<- prometheus.Metric) error {
 
 				price, err := c.PricingMap.GetCostOfStorage(d.Region(), d.StorageClass())
 				if err != nil {
+					c.logger.LogAttrs(ctx,
+						slog.LevelError,
+						err.Error(),
+						slog.String("disk_name", disk.Name),
+						slog.String("project", project),
+						slog.String("region", d.Region()),
+						slog.String("cluster_name", d.Cluster),
+						slog.String("storage_class", d.StorageClass()),
+					)
+
 					fmt.Printf("%s error getting cost of storage: %v\n", disk.Name, err)
 					continue
 				}

pkg/google/gke/gke_test.go

@@ -381,6 +381,19 @@ func TestCollector_Collect(t *testing.T) {
 									GkeClusterLabel: "test",
 								},
 							},
+							{
+								// Add in an instance that does not have a machine type that would exist in the pricing map.
+								// This test replicates and fixes https://github.com/grafana/cloudcost-exporter/issues/335
+								Name:        "test-n1-spot",
+								MachineType: "abc/n8-slim",
+								Zone:        "testing/us-central1-a",
+								Scheduling: &computev1.Scheduling{
+									ProvisioningModel: "SPOT",
+								},
+								Labels: map[string]string{
+									GkeClusterLabel: "test",
+								},
+							},
 							{
 								Name:        "test-n2-us-east1",
 								MachineType: "abc/n2-slim",