Hey,
I've noticed a hole in our current API which makes it difficult to write
external clients and other tooling around fetching the state of updates.
Currently, to fetch updates we are given two RPCs:
````
/** Gets job update summaries. */
Response getJobUpdateSummaries(1: JobUpdateQuery jobUpdateQuery)
/** Gets job update details. */
Response getJobUpdateDetails(1: JobUpdateKey key)
````
The `getJobUpdateSummaries` RPC is not scoped to a single update and
returns a
set of `JobUpdateSummary` structs. The struct is defined:
````
/** Summary of the job update including job key, user and current state. */
struct JobUpdateSummary {
/** Unique identifier for the update. */
5: JobUpdateKey key
/** User initiated an update. */
3: string user
/** Current job update state. */
4: JobUpdateState state
}
````
The `getJobUpdateDetails` RPC is scoped to a single update and returns the
following struct:
````
struct JobUpdateDetails {
/** Update definition. */
1: JobUpdate update
/** History for this update. */
2: list<JobUpdateEvent> updateEvents
/** History for the individual instances updated. */
3: list<JobInstanceUpdateEvent> instanceEvents
}
````
Maxim mentioned to me yesterday that this RPC is scoped to a single update
because assembling the `instanceEvents` can be extremely expensive. A query
that
could span more than a single update risks taking down the scheduler in a
large
cluster.
The problem I discovered is that there is no batch API to get the
inexpensive
information inside the `JobUpdate` struct. For reference this struct
contains:
````
/** Full definition of the job update. */
struct JobUpdate {
/** Update summary. */
1: JobUpdateSummary summary
/** Update configuration. */
2: JobUpdateInstructions instructions
}
````
Consumers are forced to make several `getJobUpdateDetails` calls to get
multiple
`JobUpdate` structs. Since the `JobUpdate` struct is not expensive to
assemble,
I'm proposing a new RPC that will allow consumers to get several `JobUpdate`
structs in a single call.
````
/** Gets job updates. */
Response getJobUpdates(1: JobUpdateQuery jobUpdateQuery)
````
If there are no objections, I will file tickets and put up a patch to
implement
this.
--
Zameer Manji
