API watchio

class WatchIO

Process IO watcher.

__init__ (self, pids: list = None, *, timeout: float = 600, step: float = 1, check=False)

Constructor for WatchIO, call with keyword arguments.

pids is a list of process PIDs to watch. Non-valid PIDs are silently ignored unless check is enabled.

timeout sets the default timeout value for the poll() method.

step sets the default step value, the interval we check the /proc/{pid}/io file, in seconds for the poll() method.

check raises exceptions (PermissionError if not accessible or FileNotFoundError for non-existent process) instead of silently ignoring bad pids by default.

find_pids (self, name: str) -> list

Get a list of PIDs by name. Name can be a numerical pid or the name of the process. Returns a (possibly empty) list.

get_io_data (self, pid: int) -> dict

Get IO data of the pid process. The method reads and parses the file "/proc/{pid}/io" and returns a dictionary with values in int. See https://www.kernel.org/doc/html/latest/filesystems/proc.html#proc-pid-io-display-the-io-accounting-fields for a description of the fields.

pid is the process ID to get the io data. The method returns None if the process does not exist. TODO: no read access.

main_cli ()

Unix command line interface

parse_cli (self)

Parse Unix command line arguments

poll (self, timeout: float = None, step: float = None, clear=False) -> int

Poll the IO activities. The method checks for IO activities every step seconds. It returns the number of processes with new IO activities since the last update() or poll(); or returns 0 if the wait time has exceeded timeout seconds.

timeout defaults to instance value if not given.

step defaults to instance value if not given.

clear (default is False) clears the IO counters so that polling uses only IO activities after this function has started.

update (self) -> int

Update IO activities. Returns the number of process with new IO activities since the last update() or poll(). Returns -1 if no PID is valid.