How to use gplib - 8 common examples

def get_ipaddr(host):
    (ok, out) = run('%s "%s %s | %s \\"inet\\"| %s -v \\"127.0.0\\"| %s -v \\"inet6\\""' %
                    (gplib.ssh_prefix(host=host),  ENV.IFCONFIG, 
                     ENV.IFCONFIG_TXT, ENV.GREP, ENV.GREP, ENV.GREP))

    if not ok:
        return None

    addr = []
    for l in out:
        x = l.strip().split()
        ip = x[1].split(':')
        addr.append(len(ip) == 2 and ip[1] or ip[0])
        
    return addr

def file_exists(file, host=None):
    if not host or host == 'localhost':
        return os.path.isfile(file)
    else:
        (ok, out) = run('%s test -f %s && test -r %s' % (gplib.ssh_prefix(host=host), file, file))
        return ok

def append_pg_hba(host, datadir, new_addr):
    pg_hba = os.path.join(datadir, 'pg_hba.conf')
    for addr in new_addr:
        (ok, out) = run_warn('%s "echo host all all %s/32 trust >> %s"' % 
                        (gplib.ssh_prefix(host=host), 
                         addr, pg_hba))
        if not ok:
            fatal('update %s:%s failed' % (host, pg_hba))

    return True

def postgres_active(port, host=None):
    ret = 0
    pg_lock_file = '/tmp/.s.PGSQL.%d.lock' % port
    pg_lock_netstat = 0
    pid = 0

    # ping host if present
    if host:
        ok = ping_host(host)
        if not ok:
            return (ok, pid)

    # netstat to check the port number
    (ok, out) = run('%s %s -an 2> /dev/null | %s ".s.PGSQL.%d" | %s \'{print $NF}\'| %s -F"." \'{print $NF}\' | %s -u' % 
                    (host and gplib.ssh_prefix(host=host) or '', ENV.NETSTAT, ENV.GREP, port, ENV.AWK, ENV.AWK, ENV.SORT))
    if not ok:
        return (ok, pid)

    for p_chk in out:
        p = int(p_chk)
        if p == port:
            pg_lock_netstat = port
    pg_lock_tmp = False
    if file_exists(file=pg_lock_file, host=host):
        pg_lock_tmp = True
            
    if pg_lock_netstat == 0 and pg_lock_tmp == False:
        ret = 1
        pid = 0
        log_info('No socket connection or lock file in /tmp found for %s port=%d' % (host and host or '', port))
    else:

def edit_file(host, file, search_txt, sub_txt, append=False):
    if host != 'localhost':
        gphome = os.environ.get('GPHOME')
        cmd = makeCommand('''python -c \\"import sys; sys.path.extend(['%s', '%s']); import gpmlib; gpmlib.edit_file('localhost', '%s', '%s', '%s', %s)\\"''' % 
                          (os.path.join(gphome, 'bin', 'lib'),
                           os.path.join(gphome, 'lib', 'python'),
                           file,
                           search_txt,
                           sub_txt,
                           str(append)))

        (ok, out) = run2('''%s "%s"''' % (gplib.ssh_prefix(host=host), cmd), True)
        return ok
    else:

        f = None
        tmpf = None
        tmpfile = '%s.tmp' % file
        try:
            try:
                f = open(file, 'r')
                tmpf = open(tmpfile, 'w')
                for line in f:
                    if line.find(search_txt) != -1:
                        tmpf.write(sub_txt)
                        if append:
                            tmpf.write(' # ')
                            tmpf.write(line)

def chk_multi_home(hostlist, full=True):
    hosts = full and hostlist or hostlist[0:2]
    hostnames=[]
    for host in hosts:
        (ok, out) = run('%s %s' % (gplib.ssh_prefix(host=host), ENV.HOSTNAME))
        if not ok:
            error('failed to run hostname on remote host')
        hostnames.append(out[0].strip())

    hostnames_uniq = unique(hostnames)
    return len(hostnames_uniq) != len(hostnames)

(os.path.join(ENV.GPHOME, 'bin/pg_ctl'), 
                      dst_cfg['datadir'], dst_cfg['datadir'], dst_cfg['port']))    
    (ok, out) = run_warn('%s "%s"' % 
                         (gplib.ssh_prefix(host=dst_cfg['hostname']),
                          cmd))
    if not ok:
        fatal('failed to start mirror segment %s:%s in admin mode' % (dst_cfg['hostname'], dst_cfg['datadir']))

    if force_stop:
        # stop mirror segment
        log_info('stop segment datadir=%s port=%d on %s' % (dst_cfg['datadir'], dst_cfg['port'], dst_cfg['hostname'])) 
        cmd = makeCommand('env PGOPTIONS=\\"-c gp_session_role=utility\\" %s -w stop -D %s -m smart -l %s.log' % 
                          (os.path.join(ENV.GPHOME, 'bin/pg_ctl'), 
                           dst_cfg['datadir'], dst_cfg['datadir']))
        (ok, out) = run_warn('%s "%s" >> %s 2>&1' % 
                             (gplib.ssh_prefix(host=dst_cfg['hostname']),
                              cmd,
                              logfile))        
        if not ok:
            fatal('failed to stop mirror segment %s:%s' % (dst_cfg['hostname'], dst_cfg['datadir']))
    

    log_info('sync segment datadir=%s port=%d on host %s succeeded' % (dst_cfg['datadir'], dst_cfg['port'], dst_cfg['hostname']))
    return True

if not host or host == 'localhost':
        try:
            try:
                f = open(file, 'w')
                f.close()
            except IOError, e:
                fatal('write file %s error' % file)
        finally:
            f.close()
            os.remove(file)
        
    else:
        gphome = os.environ.get('GPHOME')
        cmd = makeCommand('''python -c \\"import sys, os; sys.path.extend(['%s', '%s']); import gpmlib; gpmlib.directory_writable('%s')\\"''' %
                          (os.path.join(gphome, 'bin', 'lib'), os.path.join(gphome, 'lib', 'python'), dir))
        (ok, out) = run('''%s "%s"''' % (gplib.ssh_prefix(host=host), cmd))
        if not ok:
            fatal('write file %s error' % file)
                        
    return True