hippo

hippo is a command line utility to manage variants of your configurations and (as a side-effect) centralize them for portability, as a safe and managed alternative to the usual sysadmin route of cp my.conf my.conf.backup.

Author Rohan Prabhu [email protected]

NOTE This is a project I am using to learn Rust and to get back to a systems programming language after extensive years in managed languages and runtimes. As a result most of the upcoming changes would be refactorings as I pick up on the more rustic way of doing things; features and completeness are currently not a priority.

Usage

$ hippo snap /etc/nginx/nginx.conf
Created snapshot `2017-12-22-0255.14` for /etc/nginx/nginx.conf

$ hippo list /etc/nginx/nginx.conf
Found 2 snapshots for /etc/nginx/nginx.conf
 
1  (null)                (null)          January 1, 1970 00:00:00
2* 2017-12-22-0255.14    (no-comment)    December 22, 2017 02:55:14

Now let's say you make changes to your nginx.conf file, set it up for serving your blog. You can save a snapshot after you're done with your changes.

$ hippo snap /etc/nginx/nginx.conf blog-ready "Setup my blog"
Created snapshot `blog-ready` for /etc/nginx/nginx.conf
Old file size: 122B New file size: 180B

Now you can list the snapshots again:

$ hippo list /etc/ngnx/nginx.conf
Found 3 snapshots for /etc/nginx/nginx.conf
 
1  (null)                (null)           January 1, 1970 00:00:00
2  2017-12-22-0255.14    (no-comment)     December 22, 2017 02:55:14
3* blog-ready            Setup my blog    December 22, 2017 04:10:07

To see the diff between any two snapshots:

$ hippo diff /etc/nginx/nginx.conf 2017-12-22-0255.14 blog-ready

To see the diff between a snapshot and the current version of the file:

$ hippo diff 2017-12-22-0255.14

When using a single parameter, it will always show the diff between the current existing file on the filesystem, not necessarily the last known diff. If you have edited the file after taking a snapshot, the same will be reflected in the list command.

$ hippo list /etc/nginx/nginx.conf
Found 4 snapshots for /etc/nginx/nginx.conf
 
1  (null)                (null)           January 1, 1970 00:00:00
2  2017-12-22-0255.14    (no-comment)     December 22, 2017 02:55:14
3  blog-ready            Setup my blog    December 22, 2017 04:10:07
4* (live)                (live)           December 22, 2017 04:15:21

Any snapshot name starting and ending with a parenthesis is reserved and is not allowed.

To get a list of all configurations:

$ hippo list
/etc/nginx/nginx.conf has 4 snapshots
 
1  (null)                (null)           January 1, 1970 00:00:00
2  2017-12-22-0255.14    (no-comment)     December 22, 2017 02:55:14
3  blog-ready            Setup my blog    December 22, 2017 04:10:07
4* (live)                (live)           December 22, 2017 04:15:21
 
/home/rohan/.git/config has 2 snapshots
 
1  (null)                (null)                 January 1, 1970 00:00:00
2  base-config           Base config for git    December 22, 2017 02:55:14

Since this list can get very long, if you only want to see the controlled files:

$ hippo list --summary
/etc/nginx/nginx.conf has 4 snapshots, currently at `(live)`
/home/rohan/.git/config has 2 snapshots, currently at `base-config`

To list only specific files:

$ hippo list --summary /etc/*
/etx/nginx/nginx.conf has 4 snapshots, currently at `(live)`

Now if you have two nginx configs, one for testing your blog and one for testing your techies explosion calculator web app, you can swap between the two:

$ hippo load /etc/nginx/nginx.conf blog-ready
Loaded snapshot `blog-ready` for /etx/nginx/nginx.conf

If there have been any modifications to the file since the last snapshot, you will get an error:

$ hippo load /etc/nginx/nginx.conf techies-calculator
ERROR: The current snapshot is `(live)`. Create a snapshot for the current file
before continuing.

You can ask the load command to auto-create a snapshot:

$ hippo load --auto-snap /etc/nginx/nginx.conf techies-calculator
Created snapshot `2017-12-22-0511.22` for /etc/nginx/nginx.conf
Old file size 131B New file size 122B
Loaded snapshot `techies-calculator` for /etc/nginx/nginx.conf

You can also ask it to skip the check (not recommended) if you want to discard your changes:

$ hippo load --discard-live /etc/nginx/nginx.conf techies-calculator
WARN: The current snapshot is `(live)`. Discarding changes. The last edited version
is stored in /tmp/49jre9f99g/nginx.conf

If temporary storage is not available, or if it is not writable, then the command above will fail. There is no way around it except for creating a snapshot and then proceeding.

If you want to compress your files:

$ hippo snap --compress /etc/nginx/nginx.conf production-server

You do not have to specify any decompression required when loading a snapshot, hippo will figure out the required step on its own.