#
# NodeManager plugin - first step of handling omf_controlled slices
#

"""
Overwrites the 'resctl' tag of slivers controlled by OMF so slivermanager.py does the right thing
"""

import os, os.path
import glob
import subprocess

import tools
import logger

priority = 50

def start():
    pass

### the new template for v6
# hard-wire this for now
# once the variables are expanded, this is expected to go into
config_ple_template="""---
# Example:
# _slicename_ = nicta_ruby
# _hostname_ = planetlab1.research.nicta.com.au
# _xmpp_server_ = xmpp.planet-lab.eu
 
:uid: _slicename_@_hostname_
:uri: xmpp://_slicename_-_hostname_-<%= "#{Process.pid}" %>:_slicename_-_hostname_-<%= "#{Process.pid}" %>@_xmpp_server_
:environment: production
:debug: false
 
:auth:
  :root_cert_dir: /home/_slicename_/root_certs
  :entity_cert: /home/_slicename_/entity.crt
  :entity_key: /home/_slicename_/.ssh/id_rsa
"""

# the path where the config is expected from within the sliver
yaml_slice_path="/etc/omf_rc/config.yml"
# the path for the script that we call when a change occurs
omf_rc_trigger_script="omf_rc_plc_trigger"

### this returns the kind of virtualization on the node
# either 'vs' or 'lxc'
# also caches it in /etc/planetlab/virt for next calls
# could be promoted to core nm if need be
virt_stamp="/etc/planetlab/virt"
def get_node_virt ():
    try:
        return file(virt_stamp).read().strip()
    except:
        pass
    logger.log("Computing virt..")
    vs_retcod=subprocess.call ([ 'vserver', '--help' ])
    if vs_retcod == 0:
        virt='vs'
    else:
        virt='lxc'
    with file(virt_stamp,"w") as f:
        f.write(virt)
    return virt

def command_in_slice (slicename, argv):
    # with vserver this can be done using vserver .. exec <trigger-script>
    # with lxc this is less clear as we are still discussing how lxcsu should behave
    # ideally we'd need to run lxcsu .. <trigger-script>
    virt=get_node_virt()
    if virt=='vs':
        return [ 'vserver', slicename, 'exec', ] + argv
    elif virt=='lxc':
        return [ 'lxcsu', slicename, ] + argv
    logger.log("command_in_slice: WARNING: could not find a valid virt")
    return argv

def GetSlivers(data, conf = None, plc = None):
    logger.log("omf_resctl.GetSlivers")
    if 'accounts' not in data:
        logger.log_missing_data("omf_resctl.GetSlivers",'accounts')
        return

    try:
        xmpp_server=data['xmpp']['server']
        if not xmpp_server: 
            # we have the key but no value, just as bad
            raise Exception
    except:
        # disabled feature - bailing out
        logger.log("omf_resctl: PLC_OMF config unsufficient (not enabled, or no server set), -- plugin exiting")
        return

    hostname = data['hostname']

    def is_omf_friendly (sliver):
        for chunk in sliver['attributes']:
            if chunk['tagname']=='omf_control': return True

    for sliver in data['slivers']:
        # skip non OMF-friendly slices
        if not is_omf_friendly (sliver): continue
        slicename=sliver['name']
        yaml_template = config_ple_template
        yaml_contents = yaml_template\
            .replace('_xmpp_server_',xmpp_server)\
            .replace('_slicename_',slicename)\
            .replace('_hostname_',hostname)
        yaml_full_path="/vservers/%s/%s"%(slicename,yaml_slice_path)
        yaml_full_dir=os.path.dirname(yaml_full_path)
        if not os.path.isdir(yaml_full_dir):
            try: os.makedirs(yaml_full_dir)
            except OSError: pass

        config_changes=tools.replace_file_with_string(yaml_full_path,yaml_contents)
        logger.log("yaml_contents length=%d, config_changes=%r"%(len(yaml_contents),config_changes))
        # would make sense to also check for changes to authorized_keys 
        # would require saving a copy of that some place for comparison
        # xxx todo
        keys_changes = False
        if config_changes or keys_changes:
            # instead of restarting the service we call a companion script
            try:
                # the trigger script actually needs to be run in the slice context of course
                # xxx we might need to use
                # slice_command=['bash','-l','-c',omf_rc_trigger_script] 
                slice_command = [omf_rc_trigger_script]
                to_run = command_in_slice (slicename, slice_command)
                sp=subprocess.Popen(to_run, stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
                (out,err)=sp.communicate()
                retcod=sp.returncode
                # we don't wait for that, try to display a retcod for info purpose only
                # might be None if that config script lasts or hangs whatever
                logger.log("omf_resctl: %s: called OMF rc control script (imm. retcod=%r)"%(slicename,retcod))
                logger.log("omf_resctl: got stdout\n%s"%out)
                logger.log("omf_resctl: got stderr\n%s"%err)
            except:
                import traceback
                traceback.print_exc()
                logger.log_exc("omf_resctl: WARNING: Could not call trigger script %s"%\
                                   omf_rc_trigger_script, name=slicename)
        else:
            logger.log("omf_resctl: %s: omf_control'ed sliver has no change" % slicename)