# FUSE Mount

> Tag 13: the client names a path, an id and a kind; the server holds the id and the path against every mount the container has, opens one mount scope on the proxy, waits for its answer, and answers exactly once — mounted, overlaps, taken, or the proxy's error; the mount lives until the run ends.

Canonical: https://protocol.diverge.network/2.3.0/endpoints/containers-tools-run/client/fuse-mount/
Specification revision: 2.3.0

The client opens this channel to have one more file or directory it
serves mounted into the running container, after the id. The channel
carries the path, the client's id for the mount, and the kind; the
server makes the mount as it makes the mounts of the request, and
the asks the mount makes follow on the server channels that the id
keys.

- **The request.** The tag byte `13` followed by the path, the id and
  the kind as JSON.
  [Request](/2.3.0/endpoints/containers-tools-run/client/fuse-mount/request/) states its form.
- **The ledger.** The server holds every mount of the container: the
  volume mounts and the FUSE mounts of the request, and every FUSE
  mount made on this channel. A request whose `id` is one the server
  holds a FUSE mount under is answered with the byte `2`. A request
  whose `container_path` is a held mount's, lies inside one, or
  holds one — a volume mount's or a FUSE mount's — is answered with
  the byte `1`. The server decides the id before the path, holds the
  id and the path from the moment it decides that neither applies,
  and asks the proxy nothing for a request it refuses. Two requests
  the server cannot both make are answered one with the byte `0`
  and the other with the byte `1` or `2`, in the order the server
  decided them.
- **The mount.** The server opens exactly one mount scope on the
  proxy's connection, naming the path and the kind, and waits for
  its answer. The proxy's `Ok` is the mount made: the server answers
  with the byte `0` and the channel response finish, and relays
  every ask the mount makes after the finish, as step 9 of
  [containers::tools::run](/2.3.0/endpoints/containers-tools-run/) states. The proxy's error is the mount not
  made: the server lets go of the id and the path, and answers with
  the byte `3` followed by the error. The proxy's connection ending
  before the proxy answers is answered by a channel response finish
  that no channel response precedes.
- **The response.** Exactly one channel response, then the channel
  response finish.
  [Response](/2.3.0/endpoints/containers-tools-run/client/fuse-mount/response/) states the
  sequence.
- **The tree.** A [filetree](/2.3.0/endpoints/containers-tools-run/client/filetree/) the client
  opens after the byte `0` leaves the mount out, as it leaves out
  every FUSE mount. A filetree open when the mount is made is as it
  was opened.
- **The life of the mount.** The mount lives until the run ends.
  Nothing unmounts it, and no channel asks for that.
- **Malformed.** A channel request whose payload does not decode as
  stated, or whose `container_path` is the root or has a component
  that is empty, `.` or `..`, is answered by a channel response
  finish that no channel response precedes, and the server does
  nothing else for it.