META | DietPi-Image: Create from disk or shrink an image file

[MichaIng]

Status: WIP

ToDo:

• [ ] Clean tmpfs mount directories. In most cases there are obsolete files inside. Although this can be done as well during DietPi-PREP (mount root dev to tmp mount point, clean, umount).
  => DietPi-PREP task
• Check whether shrink loop can be replaced with only resize2fs loop. During some test running resize2fs 3 times resulted on a bid smaller file system. The 4th loop didn't change something anymore.
• @Fourdee: Which device actually requires RK_SINGLE_IMG (your script) so that the file system is written directly to the drive without partition table?
• @Fourdee: Do I get is right that GPT partitions require gdisk to run (initially and after shrink has finished), then without any actual change press w (write) and y (confirm)? So then this could be automated as well.
• Retest script with another image and see if in some circumstances the UUID of the resulting image file changes. In my case it did after many back and forth creation steps. But possibly I simply mounted the actual drive and image drive in parallel with identical UUIDs and the system automatically corrected this. Otherwise: tune2fs -U <UUID_of_initial_root_partition> $ROOT_DEV
• Automatic hash creation and 7z compression?
• Root partition as ALWAYS the last partition, right? Then we could automate root partition number estimation as well, skipping the input.

Reference: #2026 (comment)

Commit list/description:

• DietPi-Image | Create from disk or shrink an image file

[Fourdee]

@MichaIng
Doing a re-write, will commit later.

ToDo:

• GPT test
• No partition table implementation (NanoPC T4)?

Root partition as ALWAYS the last partition, right?

In my experience yes, however, could not be the case with custom setups. We should cover all options.

[Fourdee]

committed directly to dev:
https://github.com/MichaIng/DietPi/blob/dev/.meta/dietpi-imager

[MichaIng]

Prefect. Will mark this PR as closed then.

AFAIK, no partition table should not be possible. Single partition jep, but boot always requires MBR or GPT, doesn't it?

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Perhaps we can simply take the largest partition as root partition 😎?
Or we list the partitions, similar to how we list the available drives, to let choose it.

Also environment variables would be great to allow automated run. Will do some commit after DietPi-Services finished.