Added tahoe special remote.

Known problems:

1. Tries to tahoe start when daemon is already running.

2. If multiple tahoe remotes are set up on the same computer,
   they will have the same node.url configured by default,
   and this confuses tahoe commands.

This commit was sponsored by LeastAuthority.com

3 files changed, 49 insertions, 1 deletions

diff --git a/doc/git-annex.mdwn b/doc/git-annex.mdwn
index 27d4df93a..2071f515c 100644
--- a/doc/git-annex.mdwn
+++ b/doc/git-annex.mdwn
@@ -1401,6 +1401,11 @@ Here are all the supported configuration settings.
   Used to identify webdav special remotes.
   Normally this is automatically set up by `git annex initremote`.
 
+* `remote.<name>.tahoe`
+
+  Used to identify tahoe special remotes.
+  Points to the configuration directory for tahoe.
+
 * `remote.<name>.annex-xmppaddress`
 
   Used to identify the XMPP address of a Jabber buddy.
diff --git a/doc/special_remotes.mdwn b/doc/special_remotes.mdwn
index 1a87f1a19..02f9bd135 100644
--- a/doc/special_remotes.mdwn
+++ b/doc/special_remotes.mdwn
@@ -14,6 +14,7 @@ They cannot be used by other git commands though.
 * [[directory]]
 * [[rsync]]
 * [[webdav]]
+* [[tahoe]]
 * [[web]]
 * [[xmpp]]
 * [[hook]]
@@ -27,7 +28,6 @@ for using git-annex with various services:
 * [[Amazon_S3|tips/using_Amazon_S3]]
 * [[Amazon_Glacier|tips/using_Amazon_Glacier]]
 * [[tips/Internet_Archive_via_S3]]
-* [[tahoe-lafs|forum/tips:_special__95__remotes__47__hook_with_tahoe-lafs]]
 * [[Box.com|tips/using_box.com_as_a_special_remote]]
 * [[Google drive|tips/googledriveannex]]
 * [[Google Cloud Storage|tips/using_Google_Cloud_Storage]]
diff --git a/doc/special_remotes/tahoe.mdwn b/doc/special_remotes/tahoe.mdwn
new file mode 100644
index 000000000..ad87044a4
--- /dev/null
+++ b/doc/special_remotes/tahoe.mdwn
@@ -0,0 +1,43 @@
+This special remote stores file contents using
+[Tahoe-LAFS](http://tahoe-lafs.org/). There are a number of commercial
+providers, or you can build your own tahoe storage grid.
+
+Since Tahoe-LAFS encrypts all data stored in it, git-annex does not do any
+additional encryption of its own.
+
+Note that data stored in a tahoe remote cannot be dropped from it, as 
+Tahoe-LAFS does not support removing data once it is stored in the Tahoe grid.
+This, along with Tahoe's ability to recover data when some nodes fail,
+makes a tahoe special remote an excellent choice for storing backups.
+
+Typically you will have an account on a Tahoe-LAFS storage grid, which
+is represented by an "introducer furl". You need to supply this to
+git-annex in the `TAHOE_FURL` environment variable when initializing the
+remote. git-annex will then generate a tahoe configuration directory for
+the remote under `~/.tahoe/git-annex/`, and automatically start the tahoe
+daemon as needed.
+
+## configuration
+
+These parameters can be passed to `git annex initremote` to configure
+the tahoe remote.
+
+* `embedcreds` - Optional. Set to "yes" embed the tahoe credentials 
+  (specifically the introducer furl and shared-convergence-secret)
+  inside the git repository, which allows other clones to also use them
+  in order to access the tahoe grid.
+
+  Think carefully about who can access your git repository, and
+  whether you want to give them access to your tahoe system before
+  using embedcreds!
+
+Setup example:
+
+	# TAHOE_FURL=... git annex initremote tahoe type=tahoe embedcreds=yes
+
+----
+
+An older implementation of tahoe for git-annex used
+the hook special remote. It is not compatible with this newer
+implementation. See
+[[tahoe-lafs|forum/tips:_special__95__remotes__47__hook_with_tahoe-lafs]].