Add validation for single node clusters

bundle/config/validate/single_node_cluster.go

@@ -0,0 +1,135 @@
+package validate
+
+import (
+	"context"
+	"strings"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/dyn"
+	"github.com/databricks/cli/libs/dyn/convert"
+	"github.com/databricks/cli/libs/log"
+)
+
+// Validates that any single node clusters defined in the bundle are correctly configured.
+func SingleNodeCluster() bundle.ReadOnlyMutator {
+	return &singleNodeCluster{}
+}
+
+type singleNodeCluster struct{}
+
+func (m *singleNodeCluster) Name() string {
+	return "validate:SingleNodeCluster"
+}
+
+const singleNodeWarningDetail = `num_workers should be 0 only for single-node clusters. To create a
+valid single node cluster please ensure that the following properties
+are correctly set in the cluster specification:
+
+  spark_conf:
+    spark.databricks.cluster.profile: singleNode
+    spark.master: local[*]
+
+  custom_tags:
+    ResourceClass: SingleNode
+  `
+
+const singleNodeWarningSummary = `Single node cluster is not correctly configured`
+
+func showSingleNodeClusterWarning(ctx context.Context, v dyn.Value) bool {
+	// Check if the user has explicitly set the num_workers to 0. Skip the warning
+	// if that's not the case.
+	numWorkers, ok := v.Get("num_workers").AsInt()
+	if !ok || numWorkers > 0 {
+		return false
+	}
+
+	// Convenient type that contains the common fields from compute.ClusterSpec and
+	// pipelines.PipelineCluster that we are interested in.
+	type ClusterConf struct {
+		SparkConf  map[string]string `json:"spark_conf"`
+		CustomTags map[string]string `json:"custom_tags"`
+		PolicyId   string            `json:"policy_id"`
+	}
+
+	conf := &ClusterConf{}
+	err := convert.ToTyped(conf, v)
+	if err != nil {
+		return false
+	}
+
+	// If the policy id is set, we don't want to show the warning. This is because
+	// the user might have configured `spark_conf` and `custom_tags` correctly
+	// in their cluster policy.
+	if conf.PolicyId != "" {
+		return false
+	}
+
+	profile, ok := conf.SparkConf["spark.databricks.cluster.profile"]
+	if !ok {
+		log.Warnf(ctx, "spark_conf spark.databricks.cluster.profile not found in single-node cluster spec")
+		return true
+	}
+	if profile != "singleNode" {
+		log.Warnf(ctx, "spark_conf spark.databricks.cluster.profile is not singleNode in single-node cluster spec: %s", profile)
+		return true
+	}
+
+	master, ok := conf.SparkConf["spark.master"]
+	if !ok {
+		log.Warnf(ctx, "spark_conf spark.master not found in single-node cluster spec")
+		return true
+	}
+	if !strings.HasPrefix(master, "local") {
+		log.Warnf(ctx, "spark_conf spark.master does not start with local in single-node cluster spec: %s", master)
+		return true
+	}
+
+	resourceClass, ok := conf.CustomTags["ResourceClass"]
+	if !ok {
+		log.Warnf(ctx, "custom_tag ResourceClass not found in single-node cluster spec")
+		return true
+	}
+	if resourceClass != "SingleNode" {
+		log.Warnf(ctx, "custom_tag ResourceClass is not SingleNode in single-node cluster spec: %s", resourceClass)
+		return true
+	}
+
+	return false
+}
+
+func (m *singleNodeCluster) Apply(ctx context.Context, rb bundle.ReadOnlyBundle) diag.Diagnostics {
+	diags := diag.Diagnostics{}
+
+	patterns := []dyn.Pattern{
+		// Interactive clusters
+		dyn.NewPattern(dyn.Key("resources"), dyn.Key("clusters"), dyn.AnyKey()),
+		// Job clusters
+		dyn.NewPattern(dyn.Key("resources"), dyn.Key("jobs"), dyn.AnyKey(), dyn.Key("job_clusters"), dyn.AnyIndex(), dyn.Key("new_cluster")),
+		// Job task clusters
+		dyn.NewPattern(dyn.Key("resources"), dyn.Key("jobs"), dyn.AnyKey(), dyn.Key("tasks"), dyn.AnyIndex(), dyn.Key("new_cluster")),
+		// Pipeline clusters
+		dyn.NewPattern(dyn.Key("resources"), dyn.Key("pipelines"), dyn.AnyKey(), dyn.Key("clusters"), dyn.AnyIndex()),
+	}
+
+	for _, p := range patterns {
+		_, err := dyn.MapByPattern(rb.Config().Value(), p, func(p dyn.Path, v dyn.Value) (dyn.Value, error) {
+			warning := diag.Diagnostic{
+				Severity:  diag.Warning,
+				Summary:   singleNodeWarningSummary,
+				Detail:    singleNodeWarningDetail,
+				Locations: v.Locations(),
+				Paths:     []dyn.Path{p},
+			}
+
+			if showSingleNodeClusterWarning(ctx, v) {
+				diags = append(diags, warning)
+			}
+			return v, nil
+		})
+		if err != nil {
+			log.Debugf(ctx, "Error while applying single node cluster validation: %s", err)
+		}
+	}
+	return diags
+}