centralize all migration status together

[lvmxh]

now the migration status in nova is hard-code.

They are defined arbitrary.
Such as, we need a "cancelled" status, then we defined it where where want.

1. firstly
this is not a good program style.

2. this is error prone.
such as we need a list of in-progress status migrations.
we need to do the follow command to summarize all migration status firstly.
this is easy to missing some status.

$ git grep "mig.*status"
......
nova/compute/api.py: migration.status = 'confirming'
nova/compute/api.py: mig.status = 'finished'
nova/compute/api.py: if migration.status != 'running':
nova/compute/api.py: state=migration.status,
nova/compute/manager.py: # decorated function, migration status should be set to
nova/compute/manager.py: # 'error', without checking current migration status.
nova/compute/manager.py: status = migration.status
nova/compute/manager.py: migration.status = 'error'
......

[lvmxh (shaohef)]

we need to clean up these migration status.

an ideal solution

we define a new file such as status.py

def class MigeationStatus(Object):
       ERROR='error'
       RUNNING="running"
.......

This is just a simple.

Then clean up all files using migration.status hard code.

$ git grep "mig.*status" | grep .py |awk '{print $1}' |sort | uniq
nova/api/openstack/compute/server_migrations.py:
nova/compute/api.py:
nova/compute/manager.py:
nova/compute/resource_tracker.py:
nova/conductor/manager.py:
nova/conductor/tasks/live_migrate.py:
nova/db/api.py:
nova/db/api.py:def
nova/db/sqlalchemy/api.py:def
nova/db/sqlalchemy/migrate_repo/versions/216_havana.py:
nova/db/sqlalchemy/models.py:
nova/objects/migration.py:
nova/tests/functional/api_sample_tests/test_server_migrations.py:
nova/tests/unit/api/openstack/compute/test_server_migrations.py:
nova/tests/unit/compute/test_compute.py:
nova/tests/unit/compute/test_compute_api.py:
nova/tests/unit/compute/test_compute_mgr.py:
nova/tests/unit/compute/test_resource_tracker.py:
nova/tests/unit/conductor/tasks/test_live_migrate.py:
nova/tests/unit/conductor/test_conductor.py:
nova/tests/unit/db/test_db_api.py:
nova/tests/unit/objects/test_migration.py:
nova/virt/libvirt/driver.py:

[Sean Dague (sdague)]

If done, this should be like nova/compute files arch.py, task_states.py, vm_states.py

[John Garbutt (johngarbutt)]

well, an enum field in the object makes good sense to me.

[Sarafraj Singh (sarafraj-singh)]

Shaohef,
Are you working on the fix? Please change status to Inprogress if you are, otherwise change Assigned to ->nobody.