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This special remote type runs hooks that you configure to store content.
It's not recommended to use this remote type when another like [[rsync]]
or [[directory]] will do. If your hooks are not carefully written, data
could be lost.
## example
Here's a simple example that stores content on clay tablets. If you
implement this example in the real world, I'd appreciate a tour
next Apert! :) --[[Joey]]
# git config annex.cuneiform-store-hook 'tocuneiform < "$ANNEX_FILE" | tablet-writer --implement=stylus --title="$ANNEX_KEY" | tablet-proofreader | librarian --shelve --floor=$ANNEX_HASH_1 --shelf=$ANNEX_HASH_2'
# git config annex.cuneiform-retrieve-hook 'librarian --get --floor=$ANNEX_HASH_1 --shelf=$ANNEX_HASH_2 --title="$ANNEX_KEY" | tablet-reader --implement=coffee --implement=glasses --force-monastic-dedication | fromcuneiform > "$ANNEX_FILE"'
# git config annex.cuneiform-remove-hook 'goon --hit-with-hammer --floor=$ANNEX_HASH_1 --shelf=$ANNEX_HASH_2 --title="$ANNEX_KEY"'
# git config annex.cuneiform-checkpresent-hook 'librarian --find --force-distrust-catalog --floor=$ANNEX_HASH_1 --shelf=$ANNEX_HASH_2 --title="$ANNEX_KEY" --shout-title'
# git annex initremote library type=hook hooktype=cuneiform encryption=none
Can you spot the potential data loss bugs in the above simple example?
(Hint: What happens when the `tablet-proofreader` exits nonzero?)
## configuration
These parameters can be passed to `git annex initremote`:
* `encryption` - Required. Either "none" to disable encryption of content,
or a value that can be looked up (using gpg -k) to find a gpg encryption
key that will be given access to the remote. Note that additional gpg
keys can be given access to a remote by rerunning initremote with
the new key id. See [[encryption]].
* `hooktype` - Required. This specifies a collection of hooks to use for
this remote.
## hooks
Each type of hook remote is specified by a collection of hook commands.
Each hook command is run as a shell command line, and should return nonzero
on failure, and zero on success.
These environment variables are used to communicate with the hook commands:
* `ANNEX_KEY` - name of a key to store, retrieve, remove, or check.
* `ANNEX_FILE` - a file containing the key's content
* `ANNEX_HASH_1` - short stable value, based on the key, can be used for hashing
* `ANNEX_HASH_2` - another hash value, can be used for a second level of hashing
The setting to use in git config for the hook commands are as follows:
* `annex.$hooktype-store-hook` - Command run to store a key in the special remote.
`ANNEX_FILE` contains the content to be stored.
* `annex.$hooktype-retrieve-hook` - Command run to retrieve a key from the special remote.
`ANNEX_FILE` is a file that the retrieved content should be written to.
The file may already exist with a partial
copy of the content (or possibly just garbage), to allow for resuming
of partial transfers.
* `annex.$hooktype-remove-hook` - Command to remove a key from the special remote.
* `annex.$hooktype-checkpresent-hook` - Command to check if a key is present
in the special remote. Should output the key name to stdout, on its own line,
if and only if the key has been actively verified to be present in the
special remote (caching presence information is a very bad idea);
all other output to stdout will be ignored.
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