graphql-engine/cli/commands/metadata_export.go

package commands

import (
	"github.com/hasura/graphql-engine/cli"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

const longHelpMetadataExportCmd = `Export Hasura metadata and save it in migrations/metadata.yaml file.
The output is a yaml file which captures all the metadata required 
by GraphQL Engine. This includes info about tables that are tracked,
permission rules, relationships and event triggers that are defined 
on those tables.`

func newMetadataExportCmd(ec *cli.ExecutionContext) *cobra.Command {
	v := viper.New()
	opts := &metadataExportOptions{
		EC:         ec,
		actionType: "export",
	}

	metadataExportCmd := &cobra.Command{
		Use:   "export",
		Short: "Export Hasura GraphQL Engine metadata from the database",
		Example: `  # Export metadata and save it in migrations/metadata.yaml file:
  hasura metadata export`,
		SilenceUsage: true,
		PreRunE: func(cmd *cobra.Command, args []string) error {
			ec.Viper = v
			return ec.Validate()
		},
		RunE: func(cmd *cobra.Command, args []string) error {
			return opts.run()
		},
		Long: longHelpMetadataExportCmd,
	}

	f := metadataExportCmd.Flags()
	f.String("endpoint", "", "http(s) endpoint for Hasura GraphQL Engine")
	f.String("access-key", "", "access key for Hasura GraphQL Engine")

	// need to create a new viper because https://github.com/spf13/viper/issues/233
	v.BindPFlag("endpoint", f.Lookup("endpoint"))
	v.BindPFlag("access_key", f.Lookup("access-key"))

	return metadataExportCmd
}

type metadataExportOptions struct {
	EC *cli.ExecutionContext

	actionType string
}

func (o *metadataExportOptions) run() error {
	migrateDrv, err := newMigrate(o.EC.MigrationDir, o.EC.Config.ParsedEndpoint, o.EC.Config.AccessKey, o.EC.Logger)
	if err != nil {
		return err
	}
	return executeMetadata(o.actionType, migrateDrv, o.EC.MetadataFile)
}