pg_staging.py

#!/usr/bin/env python
#
# pg_staging allows to
#
import os, os.path, sys
from optparse import OptionParser

import pgstaging.options
from pgstaging.utils import NotYetImplementedException
from pgstaging.utils import CouldNotGetDumpException
from pgstaging.utils import CouldNotConnectPostgreSQLException
from pgstaging.utils import WrongNumberOfArgumentsException
from pgstaging.utils import UnknownBackupDateException
from pgstaging.utils import NoArgsCommandLineException
from pgstaging.utils import StagingRuntimeException
from pgstaging.utils import UnknownCommandException

from pgstaging.staging import Staging

import pgstaging.commands as commands

def parse_options():
    """ get the command to run from command line """

    usage  = "%prog [-c <config_filename>] command dbname <args>"
    parser = OptionParser(usage = usage)

    parser.add_option("--version", action = "store_true",
                      dest    = "version",
                      default = False,
                      help    = "show pg_staging version")

    parser.add_option("-c", "--config", dest = "config",
                      default = pgstaging.options.DEFAULT_CONFIG_FILE,
                      help    = "configuration file, defauts to %s" \
                      % pgstaging.options.DEFAULT_CONFIG_FILE)

    parser.add_option("-n", "--dry-run", action = "store_true",
                      dest    = "dry_run",
                      default = False,
                      help    = "simulate operations, don't do them")

    parser.add_option("-v", "--verbose", action = "store_true",
                      dest    = "verbose",
                      default = False,
                      help    = "be verbose and about processing progress")

    parser.add_option("-q", "--quiet", action = "store_true",
                      dest    = "terse",
                      default = False,
                      help    = "be terse, almost silent")

    parser.add_option("-d", "--debug", action = "store_true",
                      dest    = "debug",
                      default = False,
                      help    = "provide python stacktrace when error")

    parser.add_option("-t", "--tmpdir", dest = "tmpdir",
                      default = pgstaging.options.TMPDIR,
                      help    = "temp dir where to fetch dumps, %s" \
                      % pgstaging.options.TMPDIR)

    (opts, args) = parser.parse_args()

    if opts.version:
        from pgstaging.options import VERSION
        print "pg_staging %s" % VERSION
        sys.exit(0)

    pgstaging.options.DEBUG   = opts.debug
    pgstaging.options.TERSE   = opts.terse
    pgstaging.options.VERBOSE = opts.verbose or opts.debug
    pgstaging.options.DRY_RUN = opts.dry_run
    pgstaging.options.TMPDIR  = opts.tmpdir

    if pgstaging.options.TERSE and pgstaging.options.VERBOSE:
        print >>sys.stderr, "Error: can't be verbose and terse"
        sys.exit(1)

    if pgstaging.options.DRY_RUN:
        print >>sys.stderr, "Error: dry run is not yet implemented"
        sys.exit(1)

    if pgstaging.options.VERBOSE:
        print "We'll be verbose!"

    # check existence and read ability of config file
    if pgstaging.options.VERBOSE:
        print "Checking if config file '%s' exists" % opts.config

    if not os.path.exists(opts.config):
        print >>sys.stderr, \
              "Error: Configuration file %s does not exists" % opts.config
        sys.exit(1)

    if pgstaging.options.VERBOSE:
        print "Checking if config file '%s' is readable" % opts.config

    if not os.access(opts.config, os.R_OK):
        print >>sys.stderr, \
              "Error: Can't read configuration file %s" % opts.config
        print >>sys.stderr, parser.format_help()
        sys.exit(1)

    if len(args) == 0:
        if pgstaging.options.VERBOSE:
            print "No arguments, want console?"
        raise NoArgsCommandLineException, opts.config

    # we return configuration filename, command, command args
    return opts.config, args[0], args[1:]


if __name__ == '__main__':

    # first parse command line
    try:
        conffile, command, args = parse_options()

    except NoArgsCommandLineException, conffile:
        # ok I need to read docs about exceptions, conffile here ain't
        # exactly pretty

        # no args given, console mode
        if sys.stdin.isatty():
            from pgstaging.console import Console
            c = Console()
            c.set_config(str(conffile), recheck = False)

            loop = True
            while loop:
                try:
                    loop = False
                    c.cmdloop()
                except KeyboardInterrupt:
                    # don't redisplay the intro please
                    c.intro = '\n^C'
                    loop = True

            # exiting the console also exit main program
            sys.exit(0)

        else:
            # loop over input lines
            for line in sys.stdin:
                try:
                    commands.parse_input_line_and_run_command(conffile, line)
                except StagingRuntimeException, e:
                    sys.exit(1)
                except Exception, e:
                    raise

            sys.exit(0)

    try:
        commands.run_command(conffile, command, args)
    except (StagingRuntimeException, UnknownCommandException), e:
        sys.exit(1)
    except Exception, e:
        raise

    sys.exit(0)