def message_server(lock, conn):
"""The GRASS message server function designed to be a target for
multiprocessing.Process
:param lock: A multiprocessing.Lock
:param conn: A multiprocessing.Pipe
This function will use the G_* message C-functions from grass.lib.gis
to provide an interface to the GRASS C-library messaging system.
The data that is send through the pipe must provide an
identifier string to specify which C-function should be called.
The following identifers are supported:
- "INFO" Prints an info message, see G_message() for details
- "IMPORTANT" Prints an important info message,
see G_important_message() for details
- "VERBOSE" Prints a verbose message if the verbosity level is
set accordingly, see G_verbose_message() for details
- "WARNING" Prints a warning message, see G_warning() for details
- "ERROR" Prints a message with a leading "ERROR: " string,
see G_important_message() for details
- "PERCENT" Prints a percent value based on three integer values: n, d and s
see G_percent() for details
- "STOP" Stops the server function and closes the pipe
- "FATAL" Calls G_fatal_error(), this functions is only for
testing purpose
The that is end through the pipe must be a list of values:
- Messages: ["INFO|VERBOSE|WARNING|ERROR|FATAL", "MESSAGE"]
- Debug: ["DEBUG", level, "MESSAGE"]
- Percent: ["PERCENT", n, d, s]
"""
libgis.G_debug(1, "Start messenger server")
while True:
# Avoid busy waiting
conn.poll(None)
data = conn.recv()
message_type = data[0]
# Only one process is allowed to write to stderr
lock.acquire()
# Stop the pipe and the infinite loop
if message_type == "STOP":
conn.close()
lock.release()
libgis.G_debug(1, "Stop messenger server")
sys.exit()
message = data[1]
# libgis limitation
if isinstance(message, type(" ")):
if len(message) >= 2000:
message = message[:1999]
if message_type == "PERCENT":
n = int(data[1])
d = int(data[2])
s = int(data[3])
libgis.G_percent(n, d, s)
elif message_type == "DEBUG":
level = data[1]
message = data[2]
libgis.G_debug(level, message)
elif message_type == "VERBOSE":
libgis.G_verbose_message(message)
elif message_type == "INFO":
libgis.G_message(message)
elif message_type == "IMPORTANT":
libgis.G_important_message(message)
elif message_type == "WARNING":
libgis.G_warning(message)
elif message_type == "ERROR":
libgis.G_important_message("ERROR: %s" % message)
# This is for testing only
elif message_type == "FATAL":
libgis.G_fatal_error(message)
lock.release()
def _fatal_error(lock, conn, data):
"""Calls G_fatal_error()"""
libgis.G_fatal_error("Fatal Error in C library server")
def test_something(self):
libgis.G_fatal_error("Testing G_fatal_error() function call")