adds function for creating a configmap from a registry server config (#2547)

* we want to convert the reg server config to configmap

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

* lint

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

---------

Signed-off-by: ChrisJBurns <29541485+ChrisJBurns@users.noreply.github.com>

Author: ChrisJBurns

cmd/thv-operator/pkg/registryapi/config.go

@@ -3,7 +3,12 @@ package registryapi
 import (
 	"fmt"
 
+	"gopkg.in/yaml.v2"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
 	mcpv1alpha1 "github.com/stacklok/toolhive/cmd/thv-operator/api/v1alpha1"
+	ctrlutil "github.com/stacklok/toolhive/cmd/thv-operator/pkg/controllerutil"
 )
 
 // ConfigManager provides methods to build registry server configuration from MCPRegistry resources
@@ -110,6 +115,28 @@ type TagFilterConfig struct {
 	Exclude []string `yaml:"exclude,omitempty"`
 }
 
+// ToConfigMapWithContentChecksum converts the Config to a ConfigMap with a content checksum annotation
+func (c *Config) ToConfigMapWithContentChecksum(mcpRegistry *mcpv1alpha1.MCPRegistry) (*corev1.ConfigMap, error) {
+	yamlData, err := yaml.Marshal(c)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal config to YAML: %w", err)
+	}
+
+	configMap := &corev1.ConfigMap{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      fmt.Sprintf("%s-configmap", c.RegistryName),
+			Namespace: mcpRegistry.Namespace,
+			Annotations: map[string]string{
+				"toolhive.dev/content-checksum": ctrlutil.CalculateConfigHash(yamlData),
+			},
+		},
+		Data: map[string]string{
+			"config.yaml": string(yamlData),
+		},
+	}
+	return configMap, nil
+}
+
 func (*configManager) BuildConfig(mcpRegistry *mcpv1alpha1.MCPRegistry) (*Config, error) {
 	config := Config{}
 

cmd/thv-operator/pkg/registryapi/config_test.go

@@ -740,3 +740,81 @@ func TestBuildConfig_Filter(t *testing.T) {
 		assert.Empty(t, config.Filter.Tags.Exclude)
 	})
 }
+
+// TestToConfigMapWithContentChecksum tests that ToConfigMapWithContentChecksum creates
+// a ConfigMap with the correct checksum annotation based on the YAML content.
+func TestToConfigMapWithContentChecksum(t *testing.T) {
+	t.Parallel()
+
+	// Create a populated Config object
+	config := &Config{
+		RegistryName: "checksum-test-registry",
+		Source: &SourceConfig{
+			Format: "toolhive",
+			Git: &GitConfig{
+				Repository: "https://github.com/example/mcp-servers.git",
+				Branch:     "main",
+			},
+		},
+		SyncPolicy: &SyncPolicyConfig{
+			Interval: "15m",
+		},
+		Filter: &FilterConfig{
+			Names: &NameFilterConfig{
+				Include: []string{"mcp-*"},
+				Exclude: []string{"*-dev"},
+			},
+		},
+	}
+
+	mcpRegistry := &mcpv1alpha1.MCPRegistry{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-registry",
+			Namespace: "test-namespace",
+		},
+	}
+
+	// Call ToConfigMapWithContentChecksum
+	configMap, err := config.ToConfigMapWithContentChecksum(mcpRegistry)
+
+	// Verify no error occurred
+	require.NoError(t, err)
+	require.NotNil(t, configMap)
+
+	// Verify basic ConfigMap properties
+	assert.Equal(t, "checksum-test-registry-configmap", configMap.Name)
+	assert.Equal(t, "test-namespace", configMap.Namespace)
+
+	// Verify the checksum annotation exists
+	require.NotNil(t, configMap.Annotations)
+	checksum, exists := configMap.Annotations["toolhive.dev/content-checksum"]
+	require.True(t, exists, "Expected checksum annotation to exist")
+	require.NotEmpty(t, checksum, "Checksum should not be empty")
+
+	// Verify the checksum format (should be a hex string)
+	// The actual checksum is calculated by ctrlutil.CalculateConfigHash
+	assert.Regexp(t, "^[a-f0-9]+$", checksum, "Checksum should be a hex string")
+
+	// Verify the Data contains config.yaml
+	require.Contains(t, configMap.Data, "config.yaml")
+	yamlData := configMap.Data["config.yaml"]
+	require.NotEmpty(t, yamlData)
+
+	// Verify YAML content includes expected fields
+	assert.Contains(t, yamlData, "registryName: checksum-test-registry")
+	assert.Contains(t, yamlData, "repository: https://github.com/example/mcp-servers.git")
+	assert.Contains(t, yamlData, "interval: 15m")
+
+	// Test that the same config produces the same checksum
+	configMap2, err := config.ToConfigMapWithContentChecksum(mcpRegistry)
+	require.NoError(t, err)
+	checksum2 := configMap2.Annotations["toolhive.dev/content-checksum"]
+	assert.Equal(t, checksum, checksum2, "Same config should produce same checksum")
+
+	// Test that different config produces different checksum
+	config.SyncPolicy.Interval = "30m"
+	configMap3, err := config.ToConfigMapWithContentChecksum(mcpRegistry)
+	require.NoError(t, err)
+	checksum3 := configMap3.Annotations["toolhive.dev/content-checksum"]
+	assert.NotEqual(t, checksum, checksum3, "Different config should produce different checksum")
+}