Added README fro hasura module with configuration description. Updated default values of hasura config.

Author: vvuwei

config/config.go

@@ -64,8 +64,8 @@ type Hasura struct {
 type HasuraSource struct {
 	Name                  string `yaml:"name" validate:"required"`
 	DatabaseHost          string `yaml:"database_host"`
-	UsePreparedStatements bool   `yaml:"use_prepared_statements" validate:"required"`
-	IsolationLevel        string `yaml:"isolation_level" validate:"required"`
+	UsePreparedStatements bool   `yaml:"use_prepared_statements"`
+	IsolationLevel        string `yaml:"isolation_level"`
 }
 
 // UnmarshalYAML -

hasura/README.md

@@ -0,0 +1,20 @@
+# Go wrapper for Hasura metadata methods
+
+Golang's library for registration data source in Hasura service
+
+## Configuration
+
+```yaml
+hasura:
+  url: string             # hasura url, required
+  admin_secret: string    # required
+  select_limit: int       
+  allow_aggregation: bool
+  source:
+    name: string                  # name of data source, required. For more info, [hasura docs](https://hasura.io/docs/latest/api-reference/metadata-api/source/#metadata-pg-add-source-syntax).
+    database_host: string         # host of datasource, if omitted, used host from database config
+    use_prepared_statements: bool # if set to true the server prepares statement before executing on the source database (default: false)
+    isolation_level: bool         # The transaction isolation level in which the queries made to the source will be run with (options: read-committed | repeatable-read | serializable) (default: read-committed)
+  add_source: bool        # should data source be added?
+  rest: bool              # should REST endpoints be created?
+```

hasura/api.go

@@ -131,6 +131,11 @@ func (api *API) AddSource(ctx context.Context, hasura *config.Hasura, cfg config
 
 	databaseUrl := DatabaseUrl(fmt.Sprintf("postgresql://%s:%s@%s:%d/%s", cfg.User, cfg.Password, host, cfg.Port, cfg.Database))
 
+	isolationLevel := "read-committed"
+	if hasura.Source.IsolationLevel != "" {
+		isolationLevel = hasura.Source.IsolationLevel
+	}
+
 	req := Request{
 		Type: "pg_add_source",
 		Args: map[string]interface{}{
@@ -139,7 +144,7 @@ func (api *API) AddSource(ctx context.Context, hasura *config.Hasura, cfg config
 				ConnectionInfo: ConnectionInfo{
 					DatabaseUrl:           databaseUrl,
 					UsePreparedStatements: hasura.Source.UsePreparedStatements,
-					IsolationLevel:        hasura.Source.IsolationLevel,
+					IsolationLevel:        isolationLevel,
 				},
 			},
 			"replace_configuration": true,