Pre-Upgrade Handling

Cosmovisor supports custom pre-upgrade handling. Use pre-upgrade handling when you need to implement application config changes that are required in the newer version before you perform the upgrade.

Using Cosmovisor pre-upgrade handling is optional. If pre-upgrade handling is not implemented, the upgrade continues.

For example, make the required new-version changes to app.toml settings during the pre-upgrade handling. The pre-upgrade handling process means that the file does not have to be manually updated after the upgrade.

Before the application binary is upgraded, Cosmovisor calls a pre-upgrade command that can be implemented by the application.

The pre-upgrade command does not take in any command-line arguments and is expected to terminate with the following exit codes:

Exit status code	How it is handled in Cosmosvisor
0	Assumes pre-upgrade command executed successfully and continues the upgrade.
1	Default exit code when pre-upgrade command has not been implemented.
30	pre-upgrade command was executed but failed. This fails the entire upgrade.
31	pre-upgrade command was executed but failed. But the command is retried until exit code 1 or 30 are returned.

Sample

Here is a sample structure of the pre-upgrade command:

Copy func preUpgradeCommand() *cobra.Command { cmd := &cobra.Command{ Use: "pre-upgrade", Short: "Pre-upgrade command", Long: "Pre-upgrade command to implement custom pre-upgrade handling", Run: func(cmd *cobra.Command, args []string) { err := HandlePreUpgrade() if err != nil { os.Exit(30) } os.Exit(0) }, } return cmd }

Ensure that the pre-upgrade command has been registered in the application:

Copy rootCmd.AddCommand( // .. preUpgradeCommand(), // .. )