Console show/clear/connect skeleton (sonic-net#278)

* new consutil package - includes helper functions, and show/clear/connect skeletons

Signed-off-by: Cayla Wanderman-Milne <t-cawand@microsoft.com>

* Added connect command skeleton, added show line and clear line skeletons

Signed-off-by: Cayla Wanderman-Milne <t-cawand@microsoft.com>

* Added connect and consutil packages to setup.py and to bash completion

Signed-off-by: Cayla Wanderman-Milne <t-cawand@microsoft.com>

* Added docstrings and "TODO Stub" comments to clear line, show line, and connect line

Signed-off-by: Cayla Wanderman-Milne <t-cawand@microsoft.com>

clear/main.py

@@ -242,5 +242,16 @@ def clear_vlan_fdb(vlanid):
     command = 'fdbclear' + ' -v ' + vlanid
     run_command(command)
 '''
+
+#
+# 'line' command
+#
+@cli.command('line')
+@click.argument('linenum')
+def line(linenum):
+    """Clear preexisting connection to line"""
+    # TODO: Stub
+    return
+
 if __name__ == '__main__':
     cli()

connect/main.py

@@ -0,0 +1,134 @@
+#! /usr/bin/python -u
+
+import click
+import errno
+import os
+import subprocess
+import sys
+from click_default_group import DefaultGroup
+
+try:
+    # noinspection PyPep8Naming
+    import ConfigParser as configparser
+except ImportError:
+    # noinspection PyUnresolvedReferences
+    import configparser
+
+
+# This is from the aliases example:
+# https://github.com/pallets/click/blob/57c6f09611fc47ca80db0bd010f05998b3c0aa95/examples/aliases/aliases.py
+class Config(object):
+    """Object to hold CLI config"""
+
+    def __init__(self):
+        self.path = os.getcwd()
+        self.aliases = {}
+
+    def read_config(self, filename):
+        parser = configparser.RawConfigParser()
+        parser.read([filename])
+        try:
+            self.aliases.update(parser.items('aliases'))
+        except configparser.NoSectionError:
+            pass
+
+
+# Global Config object
+_config = None
+
+
+# This aliased group has been modified from click examples to inherit from DefaultGroup instead of click.Group.
+# DefaultGroup is a superclass of click.Group which calls a default subcommand instead of showing
+# a help message if no subcommand is passed
+class AliasedGroup(DefaultGroup):
+    """This subclass of a DefaultGroup supports looking up aliases in a config
+    file and with a bit of magic.
+    """
+
+    def get_command(self, ctx, cmd_name):
+        global _config
+
+        # If we haven't instantiated our global config, do it now and load current config
+        if _config is None:
+            _config = Config()
+
+            # Load our config file
+            cfg_file = os.path.join(os.path.dirname(__file__), 'aliases.ini')
+            _config.read_config(cfg_file)
+
+        # Try to get builtin commands as normal
+        rv = click.Group.get_command(self, ctx, cmd_name)
+        if rv is not None:
+            return rv
+
+        # No builtin found. Look up an explicit command alias in the config
+        if cmd_name in _config.aliases:
+            actual_cmd = _config.aliases[cmd_name]
+            return click.Group.get_command(self, ctx, actual_cmd)
+
+        # Alternative option: if we did not find an explicit alias we
+        # allow automatic abbreviation of the command.  "status" for
+        # instance will match "st".  We only allow that however if
+        # there is only one command.
+        matches = [x for x in self.list_commands(ctx)
+                   if x.lower().startswith(cmd_name.lower())]
+        if not matches:
+            # No command name matched. Issue Default command.
+            ctx.arg0 = cmd_name
+            cmd_name = self.default_cmd_name
+            return DefaultGroup.get_command(self, ctx, cmd_name)
+        elif len(matches) == 1:
+            return DefaultGroup.get_command(self, ctx, matches[0])
+        ctx.fail('Too many matches: %s' % ', '.join(sorted(matches)))
+
+def run_command(command, display_cmd=False):
+    if display_cmd:
+        click.echo(click.style("Command: ", fg='cyan') + click.style(command, fg='green'))
+
+    proc = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
+
+    while True:
+        output = proc.stdout.readline()
+        if output == "" and proc.poll() is not None:
+            break
+        if output:
+            try:
+                click.echo(output.rstrip('\n'))
+            except IOError as e:
+                # In our version of Click (v6.6), click.echo() and click.echo_via_pager() do not properly handle
+                # SIGPIPE, and if a pipe is broken before all output is processed (e.g., pipe output to 'head'),
+                # it will result in a stack trace. This is apparently fixed upstream, but for now, we silently
+                # ignore SIGPIPE here.
+                if e.errno == errno.EPIPE:
+                    sys.exit(0)
+                else:
+                    raise
+
+    rc = proc.poll()
+    if rc != 0:
+        sys.exit(rc)
+
+CONTEXT_SETTINGS = dict(help_option_names=['-h', '--help', '-?'])
+
+#
+# 'connect' group (root group)
+#
+
+# This is our entrypoint - the main "connect" command
+@click.group(cls=AliasedGroup, context_settings=CONTEXT_SETTINGS)
+def connect():
+    """SONiC command line - 'connect' command"""
+    pass
+
+#
+# 'line' command ("connect line")
+#
+@connect.command('line')
+@click.argument('linenum')
+def line(linenum):
+    """Connect to line via serial connection"""
+    # TODO: Stub
+    return
+
+if __name__ == '__main__':
+    connect()

consutil/lib.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+#
+# lib.py
+#
+# Helper code for CLI for interacting with switches via console device
+#
+
+try:
+    import click
+    import re
+    import subprocess
+    import sys
+except ImportError as e: 
+    raise ImportError("%s - required module not found" % str(e))
+
+DEVICE_PREFIX = "/dev/ttyUSB"
+
+ERR_CMD = 1
+ERR_DEV = 2
+
+# runs command, exit if stderr is written to, returns stdout otherwise
+# input: cmd (str), output: output of cmd (str)
+def popenWrapper(cmd):
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
+    output = proc.stdout.read()
+    error = proc.stderr.read()
+    if error != "":
+        click.echo("Command resulted in error: {}".format(error))
+        sys.exit(ERR_CMD)
+    return output
+
+# exits if inputted line number does not correspond to a device
+# input: linenum
+def checkDevice(linenum):
+    devices = getAllDevices()
+    if DEVICE_PREFIX + str(linenum) not in devices:
+        click.echo("Line number {} does not exist".format(linenum))
+        sys.exit(ERR_DEV)
+
+# returns a sorted list of all devices (whose name matches DEVICE_PREFIX)
+def getAllDevices():
+    cmd = "ls " + DEVICE_PREFIX + "*"
+    output = popenWrapper(cmd)
+
+    devices = output.split('\n')
+    devices = list(filter(lambda dev: re.match(DEVICE_PREFIX + r"\d+", dev) != None, devices))
+    devices.sort(key=lambda dev: int(dev[len(DEVICE_PREFIX):]))
+
+    return devices
+
+# returns a dictionary of busy devices and their info
+#     maps line number to (pid, process start time)
+def getBusyDevices():
+    cmd = 'ps -eo pid,lstart,cmd | grep -E "(mini|pico)com"'
+    output = popenWrapper(cmd)
+    processes = output.split('\n')
+
+    # matches any number of spaces then any number of digits
+    regexPid = r" *(\d+)"
+    # matches anything of form: Xxx Xxx 00 00:00:00 0000
+    regexDate = r"([A-Z][a-z]{2} [A-Z][a-z]{2} \d{2} \d{2}:\d{2}:\d{2} \d{4})"
+    # matches any non-whitespace characters ending in minicom or picocom, 
+    # then a space and any chars followed by /dev/ttyUSB<any digits>, 
+    # then a space and any chars
+    regexCmd = r"\S*(?:(?:mini)|(?:pico))com .*" + DEVICE_PREFIX + r"(\d+)(?: .*)?"
+    regexProcess = re.compile(r"^"+regexPid+r" "+regexDate+r" "+regexCmd+r"$")
+
+    busyDevices = {}
+    for process in processes:
+        match = regexProcess.match(process)
+        if match != None:
+            pid = match.group(1)
+            date = match.group(2)
+            linenum_key = match.group(3)
+            busyDevices[linenum_key] = (pid, date)
+    return busyDevices
+
+# returns baud rate of device corresponding to line number
+# input: linenum (str)
+def getBaud(linenum):
+    checkDevice(linenum)
+    cmd = "sudo stty -F " + DEVICE_PREFIX + str(linenum)
+    output = popenWrapper(cmd)
+
+    match = re.match(r"^speed (\d+) baud;", output)
+    if match != None:
+        return match.group(1)
+    else:
+        click.echo("Unable to determine baud rate")
+        return ""

consutil/main.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+#
+# main.py
+#
+# Command-line utility for interacting with switches over serial via console device
+#
+
+try:
+    import click
+    import re
+    import subprocess
+except ImportError as e: 
+    raise ImportError("%s - required module not found" % str(e))
+
+@click.group()
+def consutil():
+    """consutil - Command-line utility for interacting with switchs via console device"""
+
+    if os.geteuid() != ""
+        print "Root privileges are required for this operation"
+        sys.exit(1)
+
+# 'show' subcommand
+@consutil.command()
+def line():
+    """Show all /dev/ttyUSB lines"""
+    click.echo("show line")
+
+# 'clear' subcommand
+@consutil.command()
+@click.argument('linenum')
+def clear(linenum):
+    """Clear preexisting connection to line"""
+    click.echo("clear line linenum")
+
+# 'connect' subcommand
+@consutil.command()
+@click.argument('linenum')
+def connect(linenum):
+    """Connect to switch via console device"""
+    click.echo("connect linenum")
+
+if __name__ == '__main__':
+    consutil()

data/etc/bash_completion.d/connect

@@ -0,0 +1,8 @@
+_connect_completion() {
+    COMPREPLY=( $( env COMP_WORDS="${COMP_WORDS[*]}" \
+                   COMP_CWORD=$COMP_CWORD \
+                   _CONNECT_COMPLETE=complete $1 ) )
+    return 0
+}
+
+complete -F _connect_completion -o default connect;

data/etc/bash_completion.d/consutil

@@ -0,0 +1,8 @@
+_consutil_completion() {
+    COMPREPLY=( $( env COMP_WORDS="${COMP_WORDS[*]}" \
+                   COMP_CWORD=$COMP_CWORD \
+                   _CONSUTIL_COMPLETE=complete $1 ) )
+    return 0
+}
+
+complete -F _consutil_completion -o default consutil;

setup.py

@@ -21,6 +21,8 @@ def get_test_suite():
         'acl_loader',
         'clear',
         'config',
+        'connect',
+        'consutil',
         'counterpoll',
         'crm',
         'debug',
@@ -64,6 +66,8 @@ def get_test_suite():
         'console_scripts': [
             'acl-loader = acl_loader.main:cli',
             'config = config.main:cli',
+            'connect = connect.main:connect',
+            'consutil = consutil.main:consutil',
             'counterpoll = counterpoll.main:cli',
             'crm = crm.main:cli',
             'debug = debug.main:cli',

show/main.py

@@ -1091,5 +1091,16 @@ def reboot_cause():
         proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=True)
         click.echo(proc.stdout.read())
 
+
+#
+# 'line' command ("show line")
+#
+@cli.command('line')
+def line():
+    """Show all /dev/ttyUSB lines and their info"""
+    # TODO: Stub
+    return
+
+
 if __name__ == '__main__':
     cli()