hyprlofs
v0.0.4
Published
SmartOS hyprlofs bindings
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Hyprlofs Bindings
Hyprlofs is a SmartOS in-memory filesystem that allows consumers to map files from many disparate locations under one namespace (the hyprlofs mount). See hyprlofs(7fs) for details.
This module allows consumers to create and tear down hyprlofs mounts and modify the mappings associated with a hyprlofs mount. This interface closely resembles the underlying kernel interface without attempting to provide a higher-level abstraction. The main difference between this interface and the kernel interface is that this module's operations are asynchronous, but only one may be outstanding for a given object at any given time.
Synopsis
var mod_hyprlofs = require('hyprlofs');
var fs = new mod_hyprlofs.Filesystem('/export/mymount');
fs.mount(function (err) {
fs.addMappings([
[ '/etc/ssh/sshd_config', 'ssh_config' ],
[ '/etc/release', 'release' ],
/* ... */
], function (err) {
if (err)
throw (err);
console.log('setup complete.');
});
});
/* ... */
fs.unmount(function (err) {
if (err)
throw (err);
console.log('unmount complete');
});
Interface
This module exports a Filesystem
object on which all management operations
are performed, including:
- mount (always initially empty)
- unmount
- add files
- remove specific files
- remove all files
All operations are asynchronous. They take a "callback" argument that will be invoked upon completion with an optional "error" argument indicating whether the operation failed.
Filesystem
objects are stateless: they're essentially just a handle to work
with a given hyprlofs mount, which is identified by the mountpoint. These
objects do not keep track of the underlying mount state at all. You can even
have more than one object managing a single hyprlofs mount. This is not
recommended, since concurrently-dispatched operations will be processed in an
undefined order.
All operations other than "mount" require that the underlying hyprlofs filesystem be mounted, though not necessarily via this interface. For the most part, this is enforced by the kernel interface, which will fail operations that are attempted on non-hyprlofs mounts. But see the special note on "unmount" below.
new Filesystem(mountpoint)
: work with a hyprlofs filesystem
The constructor creates a handle for issuing subsequent hyprlofs requests. This does not mount the filesystem or create any mappings. The mountpoint itself will not be validated until it's used by one of the other methods.
fs.mount(callback)
: mount a hyprlofs filesystem
Mounts a new read-only hyprlofs filesystem at this object's mountpoint. The filesystem initially contains no mappings.
If a hyprlofs filesystem cannot be mounted at the object's mountpoint, this call will fail.
fs.unmount(callback)
: unmount a hyprlofs filesystem
Unmounts the filesystem at this object's mountpoint. This will unmount any filesystem mounted here, regardless of whether it's a hyprlofs mount. It is the caller's responsibility to ensure that this is the right thing.
fs.addMappings(mappings, callback)
: add a set of file mappings
Adds the specified mappings to the underlying hyprlofs filesystem. mappings
is an array of mappings. Each mapping is itself an array with two entries: the
full path to the file to be added, and the alias (the relative path where it
should appear) under the hyprlofs mount. See the example above for details.
If the underlying mountpoint is not a mounted hyprlofs filesystem, this call will fail.
fs.removeMappings(filenames, callback)
: remove a set of file mappings
Removes the specified mappings from the underlying hyprlofs filesystem.
filenames
is an array of aliases (relative paths) under the hyprlofs mount.
If the underlying mountpoint is not a mounted hyprlofs filesystem, this call will fail.
fs.removeAll(callback)
: removes all mappings
Removes all mappings from the underlying hyprlofs filesystem. This is useful for resetting the underlying filesystem without having to iterate the existing files (and without the associated race condition).
If the underlying mountpoint is not a mounted hyprlofs filesystem, this call will fail.
fs.listMappings(callback)
: lists all mappings
Returns (via callback) the list of all mappings on the given mount, in the same format as would be passed to addMappings.
If the underlying mountpoint is not a mounted hyprlofs filesystem, this call will fail.