Begin DRYing up ES connection resource

internal/schema/connection.go

@@ -1,32 +1,44 @@
 package schema
 
-import "github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+import (
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+)
+
+func GetConnectionResource(keyName string) *schema.Resource {
+	usernamePath := makePathRef(keyName, "username")
+	passwordPath := makePathRef(keyName, "password")
+	caDataPath := makePathRef(keyName, "ca_data")
+	caFilePath := makePathRef(keyName, "ca_file")
 
-func GetConnectionResource() *schema.Resource {
 	return &schema.Resource{
 		Schema: map[string]*schema.Schema{
 			"username": {
-				Description:  "A username to use for API authentication to Elasticsearch.",
+				Description:  "Username to use for API authentication to Elasticsearch.",
 				Type:         schema.TypeString,
 				Optional:     true,
-				RequiredWith: []string{"elasticsearch_connection.0.password"},
+				DefaultFunc:  schema.EnvDefaultFunc("ELASTICSEARCH_USERNAME", nil),
+				RequiredWith: []string{passwordPath},
 			},
 			"password": {
-				Description:  "A password to use for API authentication to Elasticsearch.",
+				Description:  "Password to use for API authentication to Elasticsearch.",
 				Type:         schema.TypeString,
 				Optional:     true,
 				Sensitive:    true,
-				RequiredWith: []string{"elasticsearch_connection.0.username"},
+				DefaultFunc:  schema.EnvDefaultFunc("ELASTICSEARCH_PASSWORD", nil),
+				RequiredWith: []string{usernamePath},
 			},
 			"api_key": {
 				Description:   "API Key to use for authentication to Elasticsearch",
 				Type:          schema.TypeString,
 				Optional:      true,
 				Sensitive:     true,
-				ConflictsWith: []string{"elasticsearch_connection.0.username", "elasticsearch_connection.0.password"},
+				DefaultFunc:   schema.EnvDefaultFunc("ELASTICSEARCH_API_KEY", nil),
+				ConflictsWith: []string{usernamePath, passwordPath},
 			},
 			"endpoints": {
-				Description: "A list of endpoints the Terraform provider will point to. They must include the http(s) schema and port number.",
+				Description: "A comma-separated list of endpoints where the terraform provider will point to, this must include the http(s) schema and port number.",
 				Type:        schema.TypeList,
 				Optional:    true,
 				Sensitive:   true,
@@ -38,20 +50,24 @@ func GetConnectionResource() *schema.Resource {
 				Description: "Disable TLS certificate validation",
 				Type:        schema.TypeBool,
 				Optional:    true,
-				Default:     false,
+				DefaultFunc: schema.EnvDefaultFunc("ELASTICSEARCH_INSECURE", false),
 			},
 			"ca_file": {
 				Description:   "Path to a custom Certificate Authority certificate",
 				Type:          schema.TypeString,
 				Optional:      true,
-				ConflictsWith: []string{"elasticsearch_connection.ca_data"},
+				ConflictsWith: []string{caDataPath},
 			},
 			"ca_data": {
 				Description:   "PEM-encoded custom Certificate Authority certificate",
 				Type:          schema.TypeString,
 				Optional:      true,
-				ConflictsWith: []string{"elasticsearch_connection.ca_file"},
+				ConflictsWith: []string{caFilePath},
 			},
 		},
 	}
 }
+
+func makePathRef(keyName string, keyValue string) string {
+	return fmt.Sprintf("%s.0.%s", keyName, keyValue)
+}

internal/utils/utils.go

@@ -124,12 +124,13 @@ func IsEmpty(v interface{}) bool {
 // Returns the common connection schema for all the Elasticsearch resources,
 // which defines the fields which can be used to configure the API access
 func AddConnectionSchema(providedSchema map[string]*schema.Schema) {
-	providedSchema["elasticsearch_connection"] = &schema.Schema{
+	keyName := "elasticsearch_connection"
+	providedSchema[keyName] = &schema.Schema{
 		Description: "Used to establish connection to Elasticsearch server. Overrides environment variables if present.",
 		Type:        schema.TypeList,
 		Optional:    true,
 		MaxItems:    1,
-		Elem:        providerSchema.GetConnectionResource(),
+		Elem:        providerSchema.GetConnectionResource(keyName),
 	}
 }
 

provider/provider.go

@@ -18,16 +18,18 @@ func init() {
 }
 
 func New(version string) func() *schema.Provider {
+	esKeyName := "elasticsearch"
+
 	return func() *schema.Provider {
 		p := &schema.Provider{
 
 			Schema: map[string]*schema.Schema{
-				"elasticsearch": {
+				esKeyName: {
 					Description: "Default Elasticsearch connection configuration block.",
 					Type:        schema.TypeList,
 					MaxItems:    1,
 					Optional:    true,
-					Elem:        providerSchema.GetConnectionResource(),
+					Elem:        providerSchema.GetConnectionResource(esKeyName),
 				},
 			},
 			DataSourcesMap: map[string]*schema.Resource{