Hi everyone,
Sorry it has taken so long to get this written. With the understanding that we
have expressed the desire to move away from Trac as the base for the project,
I'd like to put forward the following as an initial proposal for the way we
progress. You should not expect that this is high on details. I only intend to
provide some guidance around the concepts that I would like to see used. I am
hoping that this will be enough to get a reasonable idea of what the core model
might look like.
In broad terms I am proposing that we
* take the opportunity to design the project from the ground up as opposed to
attempting to build up the existing interfaces
* build the project using the Django web framework
* separate out a core sub-project with a well defined REST api for a frontend
UI sub-project to build upon
The rest of this proposal sets out to define parts of the core sub-project.
The core should provide enough services to support the main part of a issue
tracking UI. I am also expecting there to be further sub-projects to support
additional optional functionality.
The core sub-project will probably provide a basic UI to make progress ahead of
work on the UI sub-project. I am not looking to define the UI sub-project any
further in this proposal although it is likely that it will be highly dynamic,
perhaps making use of websockets. The basic UI of the core project should
remain well-maintained throughout the life of the project but at the moment my
expectation would be that it is a no-thrills interface.
Back to the core sub-project, I am looking for this to be built on the
following concepts:
#0 a change in nomenclature from product to tracker as the top level
#1 uuids for pretty much everything
#2 tickets as the accumulation of ticket change events
#3 'labels' and 'label types' as a unifying concept for categorisation of
tickets
One of the early decisions made in handling of multiple projects in bloodhound
was to call this feature multi-product. The reasoning for this was that the
term 'project' is overloaded (if I recall, there may have been an excuse to add
projects as a layer in bloodhound that could be used to group tickets across
products.) I would like to see the basic functionality brought in to handle the
ability to host multiple projects (in the top level organisation sense) but
change the nomenclature to tracker to be as generic as possible. To be fair,
the name of the feature may not matter so much as I would also like to see
users given the ability to define their levels of organisation to a greater
extent. More on this in the discussion of #3.
Note that I will use the term tracker in the rest of this proposal where you
might prefer to see product or project.
The idea behind #1, uuids, is that it may be useful to be able to unambiguously
identify instances of objects even across bloodhound instances. Pending
decisions on how tickets are referenced, these uuids could be used as a
reference that is unchanging as it moved between trackers.
How tickets are stored as a whole is also worth tackling, which is what #2 is
trying to broadly decide. Here I am suggesting that the state of a ticket can
be built up from a query that collects all the change events and applies the
deltas in order. This could prove to be a slow process so at some point we may
want to look at keeping a record of the current state or a checkpoint but,
given that ticket views are expected to show the history, these are details
that are required anyway. I suggest that we can look at optimising for speed
later. Knowing that we can update a ticket from deltas may be useful.
Finally, I am suggesting in #3 that as much as possible we generalise ticket
categorisation. Categorisation is a central concept to capture and, in trac we
inherited categorisations such as statuses (open, in progress, etc), types
(bug, enhancement, task, etc), milestones, versions, etc, and these had
separate implementations. What I would like to see is that, while we might
provide an initial set of ways to categorise tickets, we should allow users to
add the categorisations that they require. I'm suggesting calling this
generalisation 'labels' and 'label types' (though we can bikeshed that if we
like!)
There are a few ways to look at implementing labels as we could look to capture
a set of common kinds of collections so that there are types of 'label types',
as it were. What I mean by this is that you can have labels that are simply a
tag, perhaps some types of labels should have descriptions, some might have
dates associated with them. Beyond that we would need to know where a label can
be allowed to coexist on a ticket with others of the same 'label type'. A lot
of these aspects could influence how you might want to display them.
At the moment I believe that we can probably get away with a common model
across all label types and we can provide users with the tools to define what
you can do with labels of a given label type via the properties of that label
type.
As you can see I have a lot to say about these labels. Another thing that could
be useful would be to be able to have label types and labels that are available
to a specific tracker, globally or even to a set of trackers. To deliver this,
label types and labels need to be able to be associated with a variable number
of trackers.
We also need to be able to define workflows in terms of transitions between
labels and potentially how they are affected by other labels. I think it is
suffice to say that I would like to see an implementation where users are able
to define workflow transitions with a great deal of flexibility in the label
types that are involved.
>From the point of view of the transition from the trac model to the desired
>model, we can attempt to make use of Django's migrations from autogenerated
>models as brought to our attention by Daniel Brownridge. I do want to ensure
>that there is a viable migration path in place from the old bloodhound to the
>new.
I think this is about as far as I want the proposal to go for now. Obviously
there is going to be plenty more to decide.
Please let me know your thoughts.
Cheers,
Gary
