| SYSTEMD.PATH(5) | systemd.path | SYSTEMD.PATH(5) |
.SH "NAME" systemd.path - Path unit configuration
.SH "SYNOPSIS"
.PP path.path
.SH "DESCRIPTION"
.PP A unit configuration file whose name ends in .path encodes information
about a path monitored by systemd, for path-based activation.
.PP This man page lists the configuration options specific to this unit type.
See systemd.unit(5) for the common options of all unit configuration
files. The common configuration items are configured in the generic [Unit]
and [Install] sections. The path specific configuration options are
configured in the [Path] section.
.PP For each path file, a matching unit file must exist, describing the unit
to activate when the path changes. By default, a service by the same name as
the path (except for the suffix) is activated. Example: a path file foo.path
activates a matching service foo.service. The unit to activate may be
controlled by Unit= (see below).
.PP Internally, path units use the inotify(7) API to monitor file
systems. Due to that, it suffers by the same limitations as inotify, and for
example cannot be used to monitor files or directories changed by other
machines on remote NFS file systems.
.PP When a service unit triggered by a path unit terminates (regardless
whether it exited successfully or failed), monitored paths are checked
immediately again, and the service accordingly restarted instantly. As
protection against busy looping in this trigger/start cycle, a start rate
limit is enforced on the service unit, see StartLimitIntervalSec= and
StartLimitBurst= in systemd.unit(5). Unlike other service
failures, the error condition that the start rate limit is hit is propagated
from the service unit to the path unit and causes the path unit to fail as
well, thus ending the loop.
.SH "AUTOMATIC DEPENDENCIES"
.SS "Implicit Dependencies"
.PP The following dependencies are implicitly added:
.SS "Default Dependencies"
.PP The following dependencies are added unless DefaultDependencies=no
is set:
.PP
.SH "OPTIONS"
.PP Path unit files may include [Unit] and [Install] sections, which are
described in systemd.unit(5).
.PP Path unit files must include a [Path] section, which carries information
about the path or paths it monitors. The options specific to the [Path]
section of path units are the following:
.PP PathExists=, PathExistsGlob=, PathChanged=,
PathModified=, DirectoryNotEmpty=
Defines paths to monitor for certain changes: PathExists= may be used
to watch the mere existence of a file or directory. If the file specified
exists, the configured unit is activated. PathExistsGlob= works
similarly, but checks for the existence of at least one file matching the
globbing pattern specified. PathChanged= may be used to watch a file
or directory and activate the configured unit whenever it changes. It is not
activated on every write to the watched file but it is activated if the file
which was open for writing gets closed. PathModified= is similar, but
additionally it is activated also on simple writes to the watched file.
DirectoryNotEmpty= may be used to watch a directory and activate the
configured unit whenever it contains at least one file.
The arguments of these directives must be absolute file system paths.
Multiple directives may be combined, of the same and of different types, to
watch multiple paths. If the empty string is assigned to any of these
options, the list of paths to watch is reset, and any prior assignments of
these options will not have any effect.
If a path already exists (in case of PathExists= and
PathExistsGlob=) or a directory already is not empty (in case of
DirectoryNotEmpty=) at the time the path unit is activated, then the
configured unit is immediately activated as well. Something similar does not
apply to PathChanged= and PathModified=.
If the path itself or any of the containing directories are not accessible,
systemd will watch for permission changes and notice that conditions
are satisfied when permissions allow that.
Note that files whose name starts with a dot (i.e. hidden files) are
generally ignored when monitoring these paths.
.RE
.PP Unit=
The unit to activate when any of the configured paths changes. The argument
is a unit name, whose suffix is not .path. If not specified, this value
defaults to a service that has the same name as the path unit, except for
the suffix. (See above.) It is recommended that the unit name that is
activated and the unit name of the path unit are named identical, except for
the suffix.
.RE
.PP MakeDirectory=
Takes a boolean argument. If true, the directories to watch are created
before watching. This option is ignored for PathExists= settings.
Defaults to false.
.RE
.PP DirectoryMode=
If MakeDirectory= is enabled, use the mode specified here to create
the directories in question. Takes an access mode in octal notation.
Defaults to 0755.
.RE
.PP TriggerLimitIntervalSec=, TriggerLimitBurst=
Configures a limit on how often this path unit may be activated within a
specific time interval. The TriggerLimitIntervalSec= may be used to
configure the length of the time interval in the usual time units us, ms, s,
min, h, ... and defaults to 2s. See systemd.time(7) for details on
the various time units understood. The TriggerLimitBurst= setting
takes a positive integer value and specifies the number of permitted
activations per time interval, and defaults to 200. Set either to 0 to
disable any form of trigger rate limiting. If the limit is hit, the unit is
placed into a failure mode, and will not watch the paths anymore until
restarted. Note that this limit is enforced before the service activation is
enqueued.
Added in version 250.
.RE
.PP Check systemd.unit(5), systemd.exec(5), and
systemd.kill(5) for more settings.
.SH "SEE ALSO"
.PP Environment variables with details on the trigger will be set for
triggered units. See the section Environment Variables Set or Propagated by
the Service Manager in systemd.exec(5) for more details.
.PP systemd(1), systemctl(1), systemd.unit(5),
systemd.service(5), inotify(7),
systemd.directives(7)
| systemd 262.2 |