Allow caller of select_config_file to specify whether to auto-migrate config files with older versions.

By default auto migration does not happen, and the user is prompted.
During ursula run auto migration is set to true so that there are no user prompts for migration.

nucypher/cli/actions/select.py

@@ -14,9 +14,11 @@ from nucypher.cli.actions.migrate import migrate
 from nucypher.cli.literature import (
     DEFAULT_TO_LONE_CONFIG_FILE,
     GENERIC_SELECT_ACCOUNT,
+    IGNORE_OLD_CONFIGURATION,
     MIGRATE_OLD_CONFIGURATION,
     NO_ACCOUNTS,
     NO_CONFIGURATIONS_ON_DISK,
+    PROMPT_TO_MIGRATE,
     SELECT_DOMAIN,
     SELECTED_ACCOUNT,
 )
@@ -117,11 +119,13 @@ def select_domain(emitter: StdoutEmitter, message: Optional[str] = None) -> str:
     return domain
 
 
-def select_config_file(emitter: StdoutEmitter,
-                       config_class: Type[CharacterConfiguration],
-                       config_root: Optional[Path] = None,
-                       checksum_address: str = None,
-                       ) -> Path:
+def select_config_file(
+    emitter: StdoutEmitter,
+    config_class: Type[CharacterConfiguration],
+    config_root: Optional[Path] = None,
+    checksum_address: str = None,
+    do_auto_migrate: bool = False,
+) -> Path:
     """
     Selects a nucypher character configuration file from the disk automatically or interactively.
 
@@ -136,6 +140,10 @@ def select_config_file(emitter: StdoutEmitter,
     - If there are multiple character configurations on the disk in the same configuration root,
       use interactive selection.
 
+    - If the configuration file is old and:
+        1. `do_auto_migration` is False then prompt user
+        2. `do_auto_migration` is True then try migrating the file, and retry loading
+
     - Aborts if there are no configurations associated with the supplied character configuration class.
 
     """
@@ -165,14 +173,27 @@ def select_config_file(emitter: StdoutEmitter,
             parsed_config_files.append(fp)
             parsed_addresses_and_filenames.append([config_checksum_address, Path(fp).name])  # store checksum & filename
         except config_class.OldVersion as e:
-            # attempt migration
-            emitter.echo(
-                MIGRATE_OLD_CONFIGURATION.format(config_file=fp, version=e.version),
-                color="yellow",
-            )
-            migrate(emitter=emitter, config_file=fp)
-            # retry migrated file
-            continue
+            attempt_migration = True
+            if not do_auto_migrate:
+                if not click.confirm(
+                    PROMPT_TO_MIGRATE.format(config_file=fp, version=e.version)
+                ):
+                    emitter.echo(
+                        IGNORE_OLD_CONFIGURATION.format(
+                            config_file=fp, version=e.version
+                        ),
+                        color="yellow",
+                    )
+                    attempt_migration = False
+
+            if attempt_migration:
+                emitter.echo(
+                    MIGRATE_OLD_CONFIGURATION.format(config_file=fp, version=e.version),
+                    color="yellow",
+                )
+                migrate(emitter=emitter, config_file=fp)
+                # retry reading migrated file
+                continue
 
         i += 1
 

nucypher/cli/commands/ursula.py

@@ -120,9 +120,12 @@ class UrsulaConfigOptions:
             )
         else:
             if not config_file:
-                config_file = select_config_file(emitter=emitter,
-                                                 checksum_address=self.operator_address,
-                                                 config_class=UrsulaConfiguration)
+                config_file = select_config_file(
+                    emitter=emitter,
+                    checksum_address=self.operator_address,
+                    config_class=UrsulaConfiguration,
+                    do_auto_migrate=True,
+                )
             try:
                 return UrsulaConfiguration.from_configuration_file(
                     emitter=emitter,

nucypher/cli/literature.py

@@ -38,9 +38,17 @@ SUCCESSFUL_DESTRUCTION = "Successfully destroyed nucypher configuration"
 CONFIRM_FORGET_NODES = "Permanently delete all known node data?"
 SUCCESSFUL_FORGET_NODES = "Removed all stored known nodes metadata and certificates"
 
+IGNORE_OLD_CONFIGURATION = """
+Ignoring configuration file '{config_file}' whose version is too old ('{version}').
+Run `nucypher ursula config migrate --config-file '{config_file}'` to update it.
+"""
 MIGRATE_OLD_CONFIGURATION = """
 Migrating configuration file '{config_file}' whose version ('{version}') is too old.
 """
+PROMPT_TO_MIGRATE = """
+Detected configuration file '{config_file}' with old version ('{version}'). Would you 
+like to migrate this file to the newest version? 
+"""
 DEFAULT_TO_LONE_CONFIG_FILE = "Defaulting to {config_class} configuration file: '{config_file}'"
 
 #  Authentication