Module operation 

The operation handle, and what its commands take and answer. The operation object, and the filters and parameters its commands take.

An operation used to be a String here, and every command took one. That is still true — Client carries the whole lifecycle over an id — but a string is a poor thing to hand to a function, and it is nothing to reattach to. Operation is the handle: a client and an id, with the same commands on it, obtained either from an id you just started or from one you persisted before the process died.

let id = client.start_vanilla(&spec)?;
std::fs::write("run.id", &id)?;          // survive a restart

// …later, in a process that did not start it:
let op = client.attach_operation(std::fs::read_to_string("run.id")?);
op.suspend(false)?;
op.resume()?;
op.wait()?;

What the cluster says about the lifecycle

Measured on a local cluster, because none of it is obvious:

• Suspension is not a state. A suspended operation still reports running; suspended is a separate attribute, which is what Operation::suspended reads — and Operation::status reads beside the state, in one request, because a poll loop needs both. Polling the state alone will never tell you an operation is paused.
• Suspend is idempotent, resume is not. Suspending a suspended operation answers {}; resuming one that is not suspended fails with code 201, Operation is in "running" state.
• Complete is not idempotent, and behaves like Client::abort_operation: the second one is answered No such operation.
• Once the scheduler has let the operation go, every one of these answers No such operation — the rule is “the scheduler still has it”, not “it has not finished”.

Structs

Operation

A running — or finished — operation, and the client that can ask about it.

OperationEvent

One entry of an operation’s event log, as list_operation_events reports it.

OperationFilter

Which operations Client::list_operations should return.

OperationInfo

One operation, as Client::list_operations reports it.

OperationList

The answer to Client::list_operations.

OperationParameters

What Client::update_operation_parameters should change.

OperationStatus

What an operation is doing, as Client::operation_status reports it.