* feat(task): Allow tasks to run more isolated from other task systems
To allow the task internal system to be used for user created tasks as well
as checks, notification and other future additions we needed to take 2 actions:
1 - We need to use type as a first class citizen, meaning that task's have a type
and each system that will be creating tasks will set the task type through the api.
This is a change to the previous assumption that any user could set task types. This change
will allow us to have other service's white label the task service for their own purposes and not
have to worry about colissions between the types.
2 - We needed to allow other systems to add data specific to the problem they are trying to solve.
For this purpose adding a `metadata` field to the internal task system which should allow other systems to
use the task service.
These changes will allow us in the future to allow for the current check's and notifications implementations
to create a task with meta data instead of creating a check object and a task object in the database.
By allowing this new behavior checks, notifications, and user task's can all follow the same pattern:
Field an api request in a system specific http endpoint, use a small translation to the `TaskService` function call,
translate the results to what the api expects for this system, and return results.
* fix(task): undo additional check for ownerID because check is not ready
* feat(task): add limit function for task concurrency
The new task executor handles limit's differently then the old executor
instead of front loading limits by creating a runner for every task that might run
the new executor has a large worker pool and queue. This allow's us to have a unlimited
concurrency per task and helps us avoid a back log of task's execution based on a
arbitrary execution limit. This add's the ability to add an optional task execution limit
so a user can still have the advantages of limiting concurrency.
We needed the coordinator to be able to execute manual runs and resume runs.
These two functions have been added, but we also needed to allow for the executor to be
mocked out. To do that we needed to return a Promise interface instead of an actual
struct. Both these changes are to facilitate coordinator work and testing.
I chose to add a execute function that allow's the task executor to match expectation from
the scheduler but I left in the existing executor method that return's promises. This is
because I like to be able to have the accountablilty and visiblity inside what's happening
with each execution even though the promise isn't required for the scheduler. This function signature
will be used by the coordinator and potentially other's that want to ensure a 'execution' is completed.
The http error schema has been changed to simplify the outward facing
API. The `op` and `error` attributes have been dropped because they
confused people. The `error` attribute will likely be readded in some
form in the future, but only as additional context and will not be
required or even suggested for the UI to use.
Errors are now output differently both when they are serialized to JSON
and when they are output as strings. The `op` is no longer used if it is
present. It will only appear as an optional attribute if at all. The
`message` attribute for an error is always output and it will be the
prefix for any nested error. When this is serialized to JSON, the
message is automatically flattened so a nested error such as:
influxdb.Error{
Msg: errors.New("something bad happened"),
Err: io.EOF,
}
This would be written to the message as:
something bad happened: EOF
This matches a developers expectations much more easily as most
programmers assume that wrapping an error will act as a prefix for the
inner error.
This is flattened when written out to HTTP in order to make this logic
immaterial to a frontend developer.
The code is still present and plays an important role in categorizing
the error type. On the other hand, the code will not be output as part
of the message as it commonly plays a redundant and confusing role when
humans read it. The human readable message usually gives more context
and a message like with the code acting as a prefix is generally not
desired. But, the code plays a very important role in helping to
identify categories of errors and so it is very important as part of the
return response.
Implementations of the backend.Executor produce errors limited to
querying the KV store. The remainder of the errors will be processed
in the implementation of a `RunPromise`.
Fixes#15161
The current behavior is that the update is pushed into the scheduler,
and the scheduler cherry pick's what it needs. This leaves the task itself out
meaning any logging the scheduler did was not going to have the new task information in it.
docmerlin (j. Emrys Landivar)
George
Gavin Cabbage
Gavin Cabbage
Brandon Farmer
Alirie Gray
Jonathan A. Sternberg
Lyon Hill
Mustafa
elbehery
Lorenzo Affetti
Stuart Carnie