CRUD topology template

[grdw]

I have a database table with topology_templates. I'm currently trying to think about who can do what. Creating a topology_template seems like something a normal user might no be able to do but I'm no quite so sure about that. In order to remove clutter from the database we might only allow admin users to create, edit and remove topology_templates.

Editing a topology template comes with no hazard I guess if we're going to duplicate the topologies into the LES.

Deleting a topolog template also comes with no hazard.

@ChaelKruip @antw who would be able to create, update, destroy a topology template?

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TODO:

• [ ] Creating a template should make it available to the import form.
• [ ] Duplicate a topology_template into a topology when importing.
• [ ] Make it possible to create a topology_template
• [ ] Make it possible to update a topology_template
• [ ] Make it possible to delete a topology_template

[antw]

who would be able to create, update, destroy a topology template?

In my mind it would be like the current topology system, where anyone can create, update, or delete templates with a similar distinction between public and private.

We might then add a boolean featured flag which allows us to present visitors with a small selection of topologies that we have created. e.g.

+------------------------------+
| Select a topology        | v |
+------------------------------+
| Featured:                    | <- "featured" topologies created by QI
|   Three endpoints            |
|   Simple street              | 
|   Small region               |
|                              |
| Your topologies              | <- public and private templates / topologies
|   My topo. 1                 |    which I created
|   My topo. 2                 |
|                              |
| Topologies by other visitors | <- public templates / topologies created by
|   ...                        |    other people
+------------------------------+

In a perfect world, in addition to allowing a visitor to select a template when creating a LES, we would also allow them to clone the topology/template being used by any LES (this would satisfy #1499 nicely).

+------------------------------+
| Select a topology        | v |
+------------------------------+
| ...                          |
|                              |
| Your topologies              |
|   My topo. 1                 |
|   My topo. 2                 |
|   Topology from "LES A"      | <- clone the topology from a LES instead
|   Topology from "LES B"      |    of from a template
|                              |
| Topologies by other visitors |
|   ...                        |
+------------------------------+