176 lines
6.6 KiB
Plaintext
176 lines
6.6 KiB
Plaintext
/** \page page_daemon PipeWire Daemon
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The PipeWire daemon is the central process that manages data exchange between
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devices and clients.
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Typically general, users run one PipeWire daemon that listens for incoming
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connections and manages devices. Clients (including the \ref
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page_session_manager) are separate processes that talk to the daemon using the
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PipeWire socket (default: `$XDG_RUNTIME_DIR/pipewire-0`). This approach
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provides address-space separation between the privileged daemon and
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non-privileged clients.
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\dot
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digraph pw {
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compound=true;
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node [shape="box"];
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subgraph cluster_pw {
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rankdir="TB";
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label="PipeWire daemon";
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style="dashed";
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subgraph cluster_prot_native {
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label="pipewire-module-protocol-native";
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style="solid";
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socket [label="$XDG_RUNTIME_DIR/pipewire-0"];
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mod_impl [label="module implementation"];
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socket -> mod_impl;
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}
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core [label="PipeWire Core"];
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alsa [label="PipeWire ALSA support"];
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mod_impl -> core;
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core -> alsa;
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}
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kernel
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client1 [ label="Media Player" ];
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client2 [ label="Audio Software" ];
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sm [ label="Session Manager", style="dotted" ];
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client1 -> socket;
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client2 -> socket;
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sm -> socket;
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alsa -> kernel;
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}
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\enddot
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As shown above, the protocol is handled by the \ref
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page_module_protocol_native. From PipeWire's point-of-view this module is just
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another module.
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# Configuration Files
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On startup, the daemon reads a configuration file to configure itself.
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It executes a series of commands listed in the config file. The lookup order
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for configuration files are:
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- `$XDG_CONFIG_HOME/pipewire/pipewire.conf` (usually `$HOME/.config/pipewire/pipewire.conf`)
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- `$sysconfdir/pipewire/pipewire.conf` (usually `/etc/pipewire/pipewire.conf`)
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- `$datadir/pipewire/pipewire.conf` (usually `/usr/share/pipewire/pipewire.conf`)
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The first configuration file found is loaded as the base configuration.
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Next, configuration sections (from files ending with a .conf extension) are collected
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in the directories in this order:
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- `$datadir/pipewire/pipewire.conf.d/` (usually `/usr/share/pipewire/pipewire.conf.d/`)
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- `$sysconfdir/pipewire/pipewire.conf.d/` (usually `/etc/pipewire/pipewire.conf.d/`)
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- `$XDG_CONFIG_HOME/pipewire/pipewire.conf.d/` (usually `$HOME/.config/pipewire/pipewire.conf.d/`)
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They are applied to the global configuration file. Properties are overwritten
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and array elements are appended. This makes it possible to make small custom customizations
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or additions to the main configuration file.
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The environment variables `PIPEWIRE_CONFIG_DIR`, `PIPEWIRE_CONFIG_PREFIX`,
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and `PIPEWIRE_CONFIG_NAME`. Can be used to specify an alternative configuration
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directory, subdirectory, and filename respectively.
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## Configuration File Format
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PipeWire's configuration file format is JSON. In addition to true JSON
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PipeWire also understands a more compact JSON representation. Where
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`"` can be omitted around strings, no trailing commas are required and
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`:` or `=` can be used to separate object keys from their values.
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Also, `#` can be used to start a comment until the end of the line.
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The configuration file format is grouped into sections. A section is
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either a dictionary (`{}`) or an array (`[]`). Dictionary and array entries
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are separated by whitespace and may be simple value assignment, an array or
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a dictionary. For example:
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```
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# A dictionary section
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context.properties = {
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# Keys often have a dot notation
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core.daemon = true
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}
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# An array section containing three dictionary objects
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context.modules = [
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# a dictionary object with one key assigned to a string
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{ name = libpipewire-module-protocol-native }
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{ name = libpipewire-module-profiler }
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# a dictionary object with two keys, one assigned to a string
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# the other one to an array of strings
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{ name = libpipewire-module-portal
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flags = [ ifexists nofail ]
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}
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]
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```
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Allowed configuration file sections are:
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- **context.properties** (dictionary): These properties configure the
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pipewire instance.
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- **context.spa-libs** (dictionary): Maps plugin features with globs to a
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spa library.
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- **context.modules** (array): Each entry in the array is a dictionary with
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the name of the module to load, including optional args and flags. Most
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modules support being loaded multiple times.
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- **context.objects** (array): Each entry in the array is a dictionary con‐
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taining the factory to create an object from and optional extra argu‐
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ments specific to that factory.
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- **context.exec** (array): Each entry in the array is dictionary containing
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the path of a program to execute on startup and optional args. This ar‐
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ray usually contains an entry to start the session manager.
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# Logging
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The `PIPEWIRE_DEBUG` environment variable can be used to enable
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more debugging. This variable supports the following format:
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- `PIPEWIRE_DEBUG=[<level>][,<glob1>:<level1>][,<glob2>:<level2>,...]` where the globs are
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shell globs to match on log topics and the levels are the respective
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log level to set for that topic. Globs are applied in order and a matching
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glob overrides an earlier glob for that category. A level without a glob
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prefix will set the global log level and is a more preformant version of
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`*:<level>`. For example, `PIPEWIRE_DEBUG=E,mod.*:D,mod.foo:X` enables global error messages,
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debugging on all modules but no messages on the foo module.
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- `<level>` specifies the log level:
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+ `X` or `0`: No logging is enabled.
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+ `E` or `1`: Error logging is enabled.
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+ `W` or `2`: Warnings are enabled.
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+ `I` or `3`: Informational messages are enabled.
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+ `D` or `4`: Debug messages are enabled.
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+ `T` or `5`: Trace messages are enabled. These messages can be logged
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from the realtime threads.
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PipeWire uses a `category.topic` naming scheme, with the following categories:
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- `pw.*`: PipeWire internal topics.
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- `mod.*`: Module topics, for example `mod.foo` would usually refer to the
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`foo` module.
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- `ms.*`: Media session topics.
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- `ms.mod.*`: Media session modules, for example `ms.foo` would usually refer
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to the `media-session-foo` module.
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- `conn.*`: Connection specific topics such as printing raw messages sent over
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a communication socket. These are in a separate namespace as they are
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usually vastly more verbose than the normal debugging topics.
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This namespace must be explicitly enabled with a `conn.<glob>` glob.
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The behavior of the logging can be further controlled with the following
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environment variables:
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- `PIPEWIRE_LOG_SYSTEMD=false`: Disable logging to the systemd journal.
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- `PIPEWIRE_LOG=<filename>`: Redirect the log to the given filename.
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- `PIPEWIRE_LOG_LINE=false`: Don't log filename, function, and source code line.
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*/
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