migration_status: Switch to passing the path in Python.

This is an important prerequisite to changing these paths used in
provisioning.

tools/do-destroy-rebuild-database

@@ -4,10 +4,6 @@ set -x
 
 "$(dirname "$0")/../scripts/setup/terminate-psql-sessions" zulip zulip zulip_base
 
-function migration_status {
-    ./manage.py get_migration_status --settings=zproject.settings > $1
-}
-
 psql -h localhost postgres zulip <<EOF
 DROP DATABASE IF EXISTS zulip;
 CREATE DATABASE zulip TEMPLATE zulip_base;
@@ -17,7 +13,7 @@ sh "$(dirname "$0")/../scripts/setup/flush-memcached"
 
 ./manage.py purge_queue --all
 ./manage.py migrate --noinput
-migration_status "var/migration_status_dev"
+./manage.py get_migration_status --settings=zproject.settings --output="var/migration_status_dev"
 ./manage.py createcachetable third_party_api_results
 ./manage.py populate_db -n100 --threads=1
 # Ensure that the local user's API key is synced from ~/.zuliprc

tools/setup/generate-fixtures

@@ -1,10 +1,6 @@
 #!/usr/bin/env bash
 set -e
 
-function migration_status {
-    ./manage.py get_migration_status --settings=zproject.test_settings > $1
-}
-
 if  [ "$1" != "--force" ]; then
     "$(dirname "$0")/../../scripts/setup/terminate-psql-sessions" zulip zulip_test zulip_test_base zulip_test_template
     psql -h localhost postgres zulip_test << EOF
@@ -26,7 +22,8 @@ EOF
 sh "$(dirname "$0")/../../scripts/setup/flush-memcached"
 
 ./manage.py migrate --noinput --settings=zproject.test_settings
-migration_status "var/migration_status_test"
+./manage.py get_migration_status --settings=zproject.test_settings \
+    --output="var/migration_status_test"
 
 # This next line can be simplified to "-n0" once we fix our app (and tests) with 0 messages.
 ./manage.py populate_db --settings=zproject.test_settings --test-suite -n30 \

zerver/management/commands/get_migration_status.py

@@ -19,6 +19,14 @@ class Command(BaseCommand):
                             default=DEFAULT_DB_ALIAS, help='Nominates a database to synchronize. '
                             'Defaults to the "default" database.')
 
+        parser.add_argument('--output', action='store',
+                            help='Path to store the status to (default to stdout).')
+
     def handle(self, *args, **options):
         # type: (*Any, **Any) -> None
-        self.stdout.write(get_migration_status(**options))
+        result = get_migration_status(**options)
+        if options['output'] is not None:
+            with open(options['output'], 'w') as f:
+                f.write(result)
+        else:
+            self.stdout.write(result)