gpsfake

#!/usr/bin/env python
#
'''
gpsfake -- test harness for gpsd

Simulates one or more GPSes, playing back logfiles.
Most of the logic for this now lives in gps.fake,
factored out so we can write other test programs with it.
'''
#
# This file is Copyright (c) 2010 by the GPSD project
# SPDX-License-Identifier: BSD-2-clause

# This code runs compatibly under Python 2 and 3.x for x >= 2.
# Preserve this property!
from __future__ import absolute_import, print_function, division

import getopt
import os
import platform
import pty
import socket
import sys
import time

# pylint wants local modules last
try:
    import gps
    import gps.fake as gpsfake   # The "as" pacifies pychecker
except ImportError as e:
    sys.stderr.write(
        "gpsfake: can't load Python gps libraries -- check PYTHONPATH.\n")
    sys.stderr.write("%s\n" % e)
    sys.exit(1)

gps_version = '3.19'
if gps.__version__ != gps_version:
    sys.stderr.write("gpsfake: ERROR: need gps module version %s, got %s\n" %
                     (gps_version, gps.__version__))
    sys.exit(1)

try:
    my_input = raw_input
except NameError:
    my_input = input

# Get version of stdout for bytes data (NOP in Python 2)
bytesout = gps.get_bytes_stream(sys.stdout)


class Baton(object):
    "Ship progress indications to stderr."
    # By setting this > 1 we reduce the frequency of the twirl
    # and speed up test runs.  Should be relatively prime to the
    # nunber of baton states, otherwise it will cause beat artifacts
    # in the twirling.
    SPINNER_INTERVAL = 11

    def __init__(self, prompt, endmsg=None):
        self.stream = sys.stderr
        self.stream.write(prompt + "...")
        if os.isatty(self.stream.fileno()):
            self.stream.write(" \b")
        self.stream.flush()
        self.count = 0
        self.endmsg = endmsg
        self.time = time.time()
        return

    def twirl(self, ch=None):
        "Twirl the baton"
        if self.stream is None:
            return
        if os.isatty(self.stream.fileno()):
            if ch:
                self.stream.write(ch)
                self.stream.flush()
            elif self.count % Baton.SPINNER_INTERVAL == 0:
                self.stream.write("-/|\\"[self.count % 4])
                self.stream.write("\b")
                self.stream.flush()
        self.count = self.count + 1
        return

    def end(self, mesg=None):
        "Write end message"
        if mesg is None:
            mesg = self.endmsg
        if self.stream:
            self.stream.write("...(%2.2f sec) %s.\n"
                              % (time.time() - self.time, mesg))
        return


def hexdump(s):
    "Convert string to hex"
    rep = ""
    for c in s:
        rep += "%02x" % ord(c)
    return rep


def fakehook(linenumber, fakegps):
    "Do the real work"
    if not fakegps.testload.sentences:
        sys.stderr.write("fakegps: no sentences in test load.\n")
        raise SystemExit(1)
    if linenumber % len(fakegps.testload.sentences) == 0:
        if singleshot and linenumber > 0:
            return False
        if progress:
            baton.twirl('*\b')
        elif not singleshot:
            if not quiet:
                sys.stderr.write("gpsfake: log cycle of %s begins.\n"
                                 % fakegps.testload.name)
    time.sleep(cycle)
    if linedump and fakegps.testload.legend:
        ml = fakegps.testload.sentences[
            linenumber % len(fakegps.testload.sentences)].strip()
        if not fakegps.testload.textual:
            ml = hexdump(ml)
        announce = fakegps.testload.legend \
            % (linenumber % len(fakegps.testload.sentences) + 1) + ml
        if promptme:
            my_input(announce + "? ")
        else:
            print(announce)
    if progress:
        baton.twirl()
    return True


if __name__ == '__main__':
    def usage():
        "Print usage and exit"
        sys.stderr.write("""usage: gpsfake [OPTIONS] logfile...
    [-1]         logfile is interpreted once only rather than repeatedly
    [-b]         enable a twirling-baton progress indicator
    [-c cycle]   sets the delay between sentences in seconds
    [-D debug]   passes a -D option to the daemon
    [-g]         run the gpsd instance within gpsfake under control of gdb
    [-G]         run the gpsd instance within gpsfake under control of lldb
    [-h]         print a usage message and exit
    [-i]         single-stepping through logfile
    [-l]         dump a line or packet number just before each sentence
    [-m monitor] specifies a monitor program under which the daemon is run
    [-n]         start the daemon reading the GPS without waiting for a client
    [-o options] specifies options to pass to the daemon
    [-p]         sets watcher mode and dump to stdout
    [-P port]    sets the daemon's listening port
    [-q]         act in a quiet manner
    [-r initcmd] specifies an initialization command to use in pipe mode
    [-S]         insert realistic delays in the test input
    [-s speed]   sets the baud rate for the slave tty
    [-t]         force TCP
    [-T]         print some system information and exit
    [-v]         verbose
    [-V]         Version
    [-W]         specify timeout (default 60s), 0 means none
    [-x]         dump packets as gpsfake gathers them
""")
        raise SystemExit(0)

    try:
        (options, arguments) = getopt.getopt(
            sys.argv[1:],
            "1bc:D:gGhilm:no:pP:qr:s:StTuvxVW:"
            )
    except getopt.GetoptError as msg:
        print("gpsfake: " + str(msg))
        raise SystemExit(1)

    port = None
    progress = False
    cycle = 0.0
    monitor = ""
    speed = 4800
    linedump = False
    predump = False
    pipe = False
    singleshot = False
    promptme = False
    client_init = '?WATCH={"json":true,"nmea":true}'
    doptions = ""
    tcp = False
    udp = False
    verbose = 0
    slow = False
    quiet = False
    timeout = None  # Really means default
    for (switch, val) in options:
        if switch == '-1':
            singleshot = True
        elif switch == '-b':
            progress = True
        elif switch == '-c':
            cycle = float(val)
        elif switch == '-D':
            doptions += " -D " + val
        elif switch == '-g':
            monitor = "xterm -e gdb -tui --args "
            timeout = 0
        elif switch == '-G':
            monitor = "xterm -e lldb -- "
            timeout = 0
        elif switch == '-h':
            usage()
        elif switch == '-i':
            linedump = promptme = True
        elif switch == '-l':
            linedump = True
        elif switch == '-m':
            monitor = val + " "
        elif switch == '-n':
            doptions += " -n"
        elif switch == '-o':
            doptions = val
        elif switch == '-p':
            pipe = True
        elif switch == '-P':
            port = int(val)
        elif switch == '-q':
            quiet = True
        elif switch == '-r':
            client_init = val
        elif switch == '-s':
            speed = int(val)
        elif switch == '-S':
            slow = True
        elif switch == '-t':
            tcp = True
        elif switch == '-T':
            sys.stdout.write("sys %s platform %s: WRITE_PAD = %.5f\n"
                             % (sys.platform, platform.platform(),
                                gpsfake.GetDelay(slow)))
            raise SystemExit(0)
        elif switch == '-u':
            udp = True
        elif switch == '-v':
            verbose += 1
        elif switch == '-V':
            sys.stderr.write("gpsfake: Version %s\n" % gps_version)
            sys.exit(0)
        elif switch == '-W':
            try:
                timeout = int(val)
            except:
                sys.stderr.write("gpsfake: bad timeout value.\n")
                raise SystemExit(1)
        elif switch == '-x':
            predump = True

    try:
        pty.openpty()
    except (AttributeError, OSError):
        sys.stderr.write("gpsfake: ptys not available, falling back to UDP.\n")
        udp = True

    if not arguments:
        sys.stderr.write("gpsfake: requires at least one logfile argument.\n")
        raise SystemExit(1)

    if progress:
        baton = Baton("Processing %s" % ",".join(arguments), "done")
    elif not quiet:
        sys.stderr.write("Processing %s\n" % ",".join(arguments))

    # Don't allocate a private port when cycling logs for client testing.
    if port is None and not pipe:
        port = int(gps.GPSD_PORT)

    test = gpsfake.TestSession(prefix=monitor, port=port, options=doptions,
                               tcp=tcp, udp=udp, verbose=verbose,
                               predump=predump, slow=slow, timeout=timeout)

    if pipe:
        test.reporter = bytesout.write
        if verbose:
            progress = False
            test.progress = sys.stderr.write
    test.spawn()
    try:
        for logfile in arguments:
            try:
                test.gps_add(logfile, speed=speed, pred=fakehook,
                             oneshot=singleshot)
            except gpsfake.TestLoadError as e:
                sys.stderr.write("gpsfake: " + e.msg + "\n")
                raise SystemExit(1)
            except gpsfake.PacketError as e:
                sys.stderr.write("gpsfake: " + e.msg + "\n")
                raise SystemExit(1)
            except gpsfake.DaemonError as e:
                sys.stderr.write("gpsfake: " + e.msg + "\n")
                raise SystemExit(1)
            except IOError as e:
                if e.filename is None:
                    sys.stderr.write("gpsfake: unknown internal I/O error %s\n"
                                     % e)
                else:
                    sys.stderr.write("gpsfake: no such file as %s or "
                                     "file unreadable\n" % e.filename)
                raise SystemExit(1)
            except OSError:
                sys.stderr.write("gpsfake: can't open pty.\n")
                raise SystemExit(1)

        try:
            if pipe:
                test.client_add(client_init + "\n")
                # Give daemon time to get ready for the feeds.
                # Without a delay here there's a window for test
                # sentences to arrive before the watch takes effect.
                # This needs to increase if leading sentences in
                # test loads aren't being processed.
                # Until the ISYNC driver was introduced, 1 sec was
                # sufficient here. The extra 0.4s allows for the
                # additional two 200ms delays introduced by the
                # calls to gpsd_set_speed() in isync_detect()
                time.sleep(1.4)
            test.run()
        except socket.error as msg:
            sys.stderr.write("gpsfake: socket error %s.\n" % msg)
            raise SystemExit(1)
        except gps.client.json_error as e:
            sys.stderr.write("gpsfake: JSON error on line %s is %s.\n"
                             % (repr(e.data), e.explanation))
            raise SystemExit(1)
        except KeyboardInterrupt:
            sys.stderr.write("gpsfake: aborted\n")
            raise SystemExit(1)
    finally:
        test.cleanup()

    if progress:
        baton.end()

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