Usage

Type System

UCloud Python SDK has type system for runtime checking.

For example:

client.uhost().create_uhost_instance({
    'CPU': "i am not a integer",
})

it will raise ValidationException with invalid integer and some required field is miss matched.

Wait State Changed

SDK also provide state waiter helper to improver usage experience.

When using it?

Waiter can wait for remote state is achieved to target state. such as,

• create and wait for resource state is completed.
• invoke/start/stop a resource and wait for it is finished.
• custom retry policies and wait for retrying is finished.

For example:

def mget_uhost_states(uhost_ids):
    resp = client.uhost().describe_uhost_instance({'UHostIds': uhost_ids})
    return [inst.get('State') for inst in resp.get('UHostSet')]

# Stop all instances
for uhost_id in uhost_ids:
    client.uhost().stop_uhost_instance({'UHostId': uhost_id})

# Wait all instances is stopped
wait.wait_for_state(
    target=['stopped'], pending=['pending'],
    timeout=300, # wait 5min
    refresh=lambda: (
        'stopped' if all([state == 'Stopped' for state in mget_uhost_states(uhost_ids)]) else 'pending'
    ),
)

# Remove all instances
for uhost_id in uhost_ids:
    client.uhost().terminate_uhost_instance({'UHostId': uhost_id})

By the default, waiter will use exponential back-off delay between twice request. it will raise WaitTimeoutException when timeout is reached.

Client/Transport Middleware

UCloud SDK provide middleware feature to client or transport level request.

It allowed to add custom logic into the lifecycle of request/response.

For example:

@client.middleware.request
def log_params(req):
    print('[REQ]', req)

@client.middleware.response
def log_response(resp):
    print('[RESP]', resp)

or transport:

from ucloud.core.transport import RequestsTransport

transport = RequestsTransport()

@transport.middleware.request
def log_request(req):
    print('[REQ]', req)

@transport.middleware.response
def log_response(resp):
    print('[RESP]', resp)

Client({'Region': 'cn-bj2'}, transport=transport)