platform: Check valid CPU manager policy

Signed-off-by: Suraj Deshmukh <suraj@kinvolk.io>

pkg/platform/platform.go

@@ -17,6 +17,7 @@ package platform
 import (
 	"fmt"
 	"path/filepath"
+	"sort"
 
 	"github.com/hashicorp/hcl/v2"
 	"helm.sh/helm/v3/pkg/chart"
@@ -281,3 +282,36 @@ func WorkerPoolNamesUnique(pools []WorkerPool) hcl.Diagnostics {
 
 	return d
 }
+
+// CheckCPUManagerPolicy takes a map with key as worker pool name and value as the CPU Manager
+// Policy value. This function checks if the values are valid.
+func CheckCPUManagerPolicy(wp map[string]string) hcl.Diagnostics {
+	var diagnostics hcl.Diagnostics
+
+	// Gather all worker pool names.
+	wps := make([]string, len(wp))
+
+	for k := range wp {
+		wps = append(wps, k)
+	}
+
+	// Sort in ascending order to return consistent results.
+	sort.Strings(wps)
+
+	for _, name := range wps {
+		policy := wp[name]
+
+		switch policy {
+		case "", "none", "static":
+			continue
+		default:
+			diagnostics = append(diagnostics, &hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "invalid cpu_manager_policy",
+				Detail:   fmt.Sprintf("Worker pool %q has invalid cpu_manager_policy %q", name, policy),
+			})
+		}
+	}
+
+	return diagnostics
+}

pkg/platform/platform_test.go

@@ -17,6 +17,8 @@ package platform_test
 import (
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
+	"github.com/hashicorp/hcl/v2"
 	"github.com/kinvolk/lokomotive/pkg/platform"
 )
 
@@ -178,3 +180,66 @@ func TestNodeLocalDNSIsIncludedInCommonChartsWhenRequested(t *testing.T) {
 		t.Fatalf("NodeLocalDNS should be included in charts list when requested")
 	}
 }
+
+func TestCheckCPUManagerPolicy(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		wp   map[string]string
+		want hcl.Diagnostics
+	}{
+		{
+			name: "valid_cpu_manager_policy_values",
+			wp: map[string]string{
+				"wp_a": "",
+				"wp_b": "static",
+				"wp_c": "none",
+			},
+			want: nil,
+		},
+		{
+			name: "invalid_cpu_manager_policy_value",
+			wp: map[string]string{
+				"wp_a":   "",
+				"foobar": "foobar",
+			},
+			want: hcl.Diagnostics{&hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "invalid cpu_manager_policy",
+				Detail:   "Worker pool \"foobar\" has invalid cpu_manager_policy \"foobar\"",
+			}},
+		},
+		{
+			name: "all_invalid_values",
+			wp: map[string]string{
+				"foo": "foo",
+				"bar": "bar",
+			},
+			want: hcl.Diagnostics{
+				&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "invalid cpu_manager_policy",
+					Detail:   "Worker pool \"bar\" has invalid cpu_manager_policy \"bar\"",
+				},
+				&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "invalid cpu_manager_policy",
+					Detail:   "Worker pool \"foo\" has invalid cpu_manager_policy \"foo\"",
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := platform.CheckCPUManagerPolicy(tt.wp)
+			if diff := cmp.Diff(got, tt.want); diff != "" {
+				t.Errorf("got unexpected diagnostics: -want +got\n%s", diff)
+			}
+		})
+	}
+}