Mount types

The "mounts" hash is the primary mechanism for adding data to the container at runtime (beyond what is already in the container image).

Each value of the "mounts" hash is itself a hash, whose "kind" key determines the handler used to attach data to the container.

table(table table-bordered table-condensed).
|_. Mount type|_. Kind|_. Description|_. Examples|
|Arvados data collection|@collection@|@"portable_data_hash"@ _or_ @"uuid"@ _may_ be provided. If not provided, a new collection will be created. This is useful when @"writable":true@ and the container's @output_path@ is (or is a subdirectory of) this mount target.
@"writable"@ may be provided with a @true@ or @false@ to indicate the path must (or must not) be writable. If not specified, the system can choose.
@"path"@ may be provided, and defaults to @"/"@.
At container startup, the target path will have the same directory structure as the given path within the collection. Even if the files/directories are writable in the container, modifications will _not_ be saved back to the original collections when the container ends.|<pre><code>{
 "kind":"collection",
 "uuid":"...",
 "path":"/foo.txt"
}
{
 "kind":"collection",
 "uuid":"..."
}</code></pre>|
|Git tree|@git_tree@|One of { @"git-url"@, @"repository_name"@, @"uuid"@ } must be provided.
One of { @"commit"@, @"revisions"@ } must be provided.
"path" may be provided. The default path is "/".
At container startup, the target path will have the source tree indicated by the given revision. The @.git@ metadata directory _will not_ be available: typically the system will use @git-archive@ rather than @git-checkout@ to prepare the target directory.
- If a value is given for @"revisions"@, it will be resolved to a set of commits (as desribed in the "ranges" section of git-revisions(1)) and the container request will be satisfiable by any commit in that set.
- If a value is given for @"commit"@, it will be resolved to a single commit, and the tree resulting from that commit will be used.
- @"path"@ can be used to select a subdirectory or a single file from the tree indicated by the selected commit.
- Multiple commits can resolve to the same tree: for example, the file/directory given in @"path"@ might not have changed between commits A and B.
- The resolved mount (found in the Container record) will have only the "kind" key and a "blob" or "tree" key indicating the 40-character hash of the git tree/blob used.|<pre><code>{
 "kind":"git_tree",
 "uuid":"zzzzz-s0uqq-xxxxxxxxxxxxxxx",
 "commit":"master"
}
{
 "kind":"git_tree",
 "uuid":"zzzzz-s0uqq-xxxxxxxxxxxxxxx",
 "commit_range":"bugfix^..master",
 "path":"/crunch_scripts/grep"
}</code></pre>|
|Temporary directory|@tmp@|@"capacity"@: capacity (in bytes) of the storage device.
@"device_type"@ (optional, default "network"): one of @{"ram", "ssd", "disk", "network"}@ indicating the acceptable level of performance.
At container startup, the target path will be empty. When the container finishes, the content will be discarded. This will be backed by a storage mechanism no slower than the specified type.|<pre><code>{
 "kind":"tmp",
 "capacity":100000000000
}
{
 "kind":"tmp",
 "capacity":1000000000,
 "device_type":"ram"
}</code></pre>|
|Keep|@keep@|Expose all readable collections via arv-mount.
Requires suitable runtime constraints.|<pre><code>{
 "kind":"keep"
}</code></pre>|
|Mounted file or directory|@file@|@"path"@: absolute path (inside the container) of a file or directory that is (or is inside) another mount target.
Can be used for "stdin" and "stdout" targets.|<pre><code>{
 "kind":"file",
 "path":"/mounted_tmp/a.out"
}</code></pre>|
|JSON document|@json@|A JSON-encoded string, array, or object.|<pre>{
 "kind":"json",
 "content":{"foo":"bar"}
}</pre>|