Simplified template creation

[grossmj]

Creating a new template isn't always a smooth experience and I am looking for a way to simplify this.

Currently in v2, an user can create a template in 2 ways:

• By manually providing all settings (in Edit -> Preferences)
• By selecting an appliance provided that all images have been found locally or on the controller.

Create a template after an image has been uploaded

The user uploads an image to the controller which then automatically create a new template by matching the image checksum with an appliance info.

• The controller automatically download missing images to create the template (if they can be freely downloaded).

• A template cannot be created until all required images are uploaded / downloaded / found on the controller for a given appliance version.

Example:

1. The user uploads thevios-adventerprisek9-m.spa.159-3.m3.qcow2 image to the controller.

2. The controller use the image checksum to find the appliance referencing that checksum: https://github.com/GNS3/gns3-registry/blob/master/appliances/cisco-iosv.gns3a

3. Now the controller knows that the version is "15.9(3)M3" and 2 images are required to create a new template. The "IOSv_startup_config.img" image is not locally available, the controller then download that image since it is free to download.

4. The controller create the template using all the info found in the appliance file.

This method would be very easy for users but only works if an image if referenced in an appliance file.

Also, I think we should have some sort of versioning for templates so one template can have multiple images OR we can have multiple template with the same name and a version field.