# -*- coding: utf-8 -*-
#
# Copyright (C) 2007-2010 Edgewall Software
# Copyright (C) 2005-2007 Christopher Lenz <cmlenz@gmx.de>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://bitten.edgewall.org/wiki/License.

"""Implementation of the build slave."""

from datetime import datetime
import errno
import urllib
import urllib2
import logging
import os
import platform
import shutil
import socket
import sys
import tempfile
import time
import re
import cookielib
import threading
import mimetools
from ConfigParser import MissingSectionHeaderError

from bitten import PROTOCOL_VERSION
from bitten.build import BuildError
from bitten.build.config import Configuration, ConfigFileNotFound
from bitten.recipe import Recipe
from bitten.util import xmlio
from bitten.util.compat import HTTPBasicAuthHandler

EX_OK = getattr(os, "EX_OK", 0)
EX_UNAVAILABLE = getattr(os, "EX_UNAVAILABLE", 69)
EX_IOERR = getattr(os, "EX_IOERR", 74)
EX_PROTOCOL = getattr(os, "EX_PROTOCOL", 76)
EX_NOPERM = getattr(os, "EX_NOPERM", 77)

FORM_TOKEN_RE = re.compile('__FORM_TOKEN\" value=\"(.+)\"')

__all__ = ['BuildSlave', 'ExitSlave']
__docformat__ = 'restructuredtext en'

log = logging.getLogger('bitten.slave')

# List of network errors which are usually temporary and non critical.
temp_net_errors = [errno.ENETUNREACH, errno.ENETDOWN, errno.ETIMEDOUT,
                   errno.ECONNREFUSED]

def _rmtree(root):
    """Catch shutil.rmtree failures on Windows when files are read-only, and only remove if root exists."""
    def _handle_error(fn, path, excinfo):
       os.chmod(path, 0666)
       fn(path)
    if os.path.exists(root):
        return shutil.rmtree(root, onerror=_handle_error) 
    else:
        return False


class SaneHTTPRequest(urllib2.Request):

    def __init__(self, method, url, data=None, headers={}):
        urllib2.Request.__init__(self, url, data, headers)
        self.method = method

    def get_method(self):
        if self.method is None:
            self.method = self.has_data() and 'POST' or 'GET'
        return self.method


def encode_multipart_formdata(fields):
    """
    Given a dictionary field parameters, returns the HTTP request body and the
    content_type (which includes the boundary string), to be used with an
    httplib-like call.

    Normal key/value items are treated as regular parameters, but key/tuple
    items are treated as files, where a value tuple is a (filename, data) tuple.

    For example::

        fields = {
            'foo': 'bar',
            'foofile': ('foofile.txt', 'contents of foofile'),
        }
        body, content_type = encode_multipart_formdata(fields)
    
    Note: Adapted from http://code.google.com/p/urllib3/ (MIT license)
    """

    BOUNDARY = mimetools.choose_boundary()
    ENCODE_TEMPLATE= "--%(boundary)s\r\n" \
        "Content-Disposition: form-data; name=\"%(name)s\"\r\n" \
        "\r\n%(value)s\r\n"
    ENCODE_TEMPLATE_FILE = "--%(boundary)s\r\n" \
        "Content-Disposition: form-data; name=\"%(name)s\"; " \
                "filename=\"%(filename)s\"\r\n" \
        "Content-Type: %(contenttype)s\r\n" \
        "\r\n%(value)s\r\n"

    body = ""
    for key, value in fields.iteritems():
        if isinstance(value, tuple):
            filename, value = value
            body += ENCODE_TEMPLATE_FILE % {
                        'boundary': BOUNDARY,
                        'name': str(key),
                        'value': str(value),
                        'filename': str(filename),
                        'contenttype': 'application/octet-stream'
                    }
        else:
            body += ENCODE_TEMPLATE % {
                        'boundary': BOUNDARY,
                        'name': str(key),
                        'value': str(value)
                    }
    body += '--%s--\r\n' % BOUNDARY
    content_type = 'multipart/form-data; boundary=%s' % BOUNDARY
    return body, content_type


class KeepAliveThread(threading.Thread):
    "A thread to periodically send keep-alive messages to the master"
    
    def __init__(self, opener, build_url, single_build, keepalive_interval):
        threading.Thread.__init__(self, None, None, "KeepaliveThread")
        self.build_url = build_url
        self.keepalive_interval = keepalive_interval
        self.single_build = single_build
        self.last_keepalive = int(time.time())
        self.kill = False
        self.opener = opener

    def keepalive(self):
        log.debug('Sending keepalive')
        method = 'POST'
        url = self.build_url + '/keepalive/'
        body = None
        shutdown = False
        headers = {
            'Content-Type': 'application/x-bitten+xml',
            'Content-Length': '0'
            }
        log.debug('Sending %s request to %r', method, url)
        req = SaneHTTPRequest(method, url, body, headers or {})
        try:
            return self.opener.open(req)
        except urllib2.HTTPError, e:
            # a conflict error lets us know that we've been
            # invalidated. Ideally, we'd engineer something to stop any
            # running steps in progress, but killing threads is tricky
            # stuff. For now, we'll wait for whatever's going
            # on to stop, and the main thread'll figure out that we've
            # been invalidated.
            log.warning('Server returned keepalive error %d: %s', e.code, e.msg)
        except:
            log.warning('Server returned unknown keepalive error')

    def run(self):
        log.debug('Keepalive thread starting.')
        while (not self.kill):
            now = int(time.time())
            if (self.last_keepalive + self.keepalive_interval) < now:
                self.keepalive()
                self.last_keepalive = now
            
            time.sleep(1)
        log.debug('Keepalive thread exiting.')

    def stop(self):
        log.debug('Stopping keepalive thread')
        self.kill = True
        self.join(30)
        log.debug('Keepalive thread stopped')
        

class BuildSlave(object):
    """HTTP client implementation for the build slave."""

    def __init__(self, urls, name=None, config=None, dry_run=False,
                 work_dir=None, build_dir="build_${build}",
                 keep_files=False, single_build=False,
                 poll_interval=300, keepalive_interval = 60,
                 username=None, password=None,
                 dump_reports=False, no_loop=False, form_auth=False):
        """Create the build slave instance.
        
        :param urls: a list of URLs of the build masters to connect to, or a
                     single-element list containing the path to a build recipe
                     file
        :param name: the name with which this slave should identify itself
        :param config: the path to the slave configuration file
        :param dry_run: wether the build outcome should not be reported back
                        to the master
        :param work_dir: the working directory to use for build execution
        :param build_dir: the pattern to use for naming the build subdir
        :param keep_files: whether files and directories created for build
                           execution should be kept when done
        :param single_build: whether this slave should exit after completing a 
                             single build, or continue processing builds forever
        :param poll_interval: the time in seconds to wait between requesting
                              builds from the build master (default is five
                              minutes)
        :param keepalive_interval: the time in seconds to wait between sending
                                    keepalive heartbeats (default is 30 seconds)
        :param username: the username to use when authentication against the
                         build master is requested
        :param password: the password to use when authentication is needed
        :param dump_reports: whether report data should be written to the
                             standard output, in addition to being transmitted
                             to the build master
        :param no_loop: for this slave to just perform a single check, regardless
                        of whether a build is done or not
        :param form_auth: login using AccountManager HTML form instead of
                                HTTP authentication for all urls
        """
        self.local = len(urls) == 1 and not urls[0].startswith('http://') \
                                    and not urls[0].startswith('https://')
        if self.local:
            self.urls = urls
        else:
            self.urls = [
                not url.endswith('/builds') and url.rstrip('/') + '/builds'
                or url for url in urls]

        if name is None:
            name = platform.node().split('.', 1)[0].lower()
        self.name = name
        self.config = Configuration(config)
        self.dry_run = dry_run
        if not work_dir:
            work_dir = tempfile.mkdtemp(prefix='bitten')
        elif not os.path.exists(work_dir):
            os.makedirs(work_dir)
        self.work_dir = work_dir
        self.build_dir = build_dir
        self.keep_files = keep_files
        self.single_build = single_build
        self.no_loop = no_loop
        self.poll_interval = poll_interval
        self.keepalive_interval = keepalive_interval
        self.dump_reports = dump_reports
        self.cookiejar = cookielib.CookieJar()
        self.username = username \
                        or self.config['authentication.username'] or ''

        if not self.local:
            self.password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
            if self.username:
                log.debug('Enabling authentication with username %r',
                                self.username)
                self.form_auth = form_auth
                password = password \
                           or self.config['authentication.password'] or ''
                self.config.packages.pop('authentication', None)
                urls = [url[:-len('/builds')] for url in self.urls]
                self.password_mgr.add_password(
                                None, urls, self.username, password)
                self.auth_map = dict(map(lambda x: (x, False), urls))

    def _get_opener(self):
        opener = urllib2.build_opener(urllib2.HTTPErrorProcessor())
        opener.add_handler(HTTPBasicAuthHandler(self.password_mgr))
        opener.add_handler(urllib2.HTTPDigestAuthHandler(self.password_mgr))
        opener.add_handler(urllib2.HTTPCookieProcessor(self.cookiejar))
        return opener
    opener = property(_get_opener)

    def request(self, method, url, body=None, headers=None):
        log.debug('Sending %s request to %r', method, url)
        req = SaneHTTPRequest(method, url, body, headers or {})
        try:
            resp = self.opener.open(req)
            if not hasattr(resp, 'code'):
                resp.code = 200
            return resp
        except urllib2.HTTPError, e:
            if e.code >= 300:
                if hasattr(e, 'headers') and \
                            e.headers.getheader('Content-Type', ''
                                        ).startswith('text/plain'):
                    content = e.read()
                else:
                    content = 'no message available'
                log.debug('Server returned error %d: %s (%s)',
                                        e.code, e.msg, content)
                raise
            return e

    def run(self):
        if self.local:
            fileobj = open(self.urls[0])
            try:
                self._execute_build(None, fileobj)
            finally:
                fileobj.close()
            return EX_OK

        urls = []
        while True:
            if not urls:
                urls[:] = self.urls
            url = urls.pop(0)
            try:
                try:
                    if self.username and not self.auth_map.get(url):
                        login_url = '%s/login?referer=%s' % (url[:-7],
                                                        urllib.quote_plus(url))
                        # First request to url, authentication needed
                        if self.form_auth:
                            log.debug('Performing http form authentication')
                            resp = self.request('POST', login_url)
                            match = FORM_TOKEN_RE.search(resp.read())
                            if not match:
                                log.error("Project %s does not support form "
                                          "authentication" % url[:-7])
                                raise ExitSlave(EX_NOPERM)
                            values = {'user': self.username, 
                                      'password':
                                          self.password_mgr.find_user_password(
                                                                None, url)[1],
                                      'referer': '',
                                      '__FORM_TOKEN': match.group(1)} 
                            self.request('POST', login_url,
                                         body=urllib.urlencode(values))
                        else:
                            log.debug('Performing basic/digest authentication')
                            self.request('HEAD', login_url)
                        self.auth_map[url] = True
                    elif self.username:
                        log.debug('Reusing authentication information.')
                    else:
                        log.debug('Authentication not provided. Attempting to '
                                  'execute build anonymously.')
                    job_done = self._create_build(url)
                    if job_done:
                        continue
                except urllib2.HTTPError, e:
                    # HTTPError doesn't have the "reason" attribute of URLError
                    log.error(e)
                    raise ExitSlave(EX_UNAVAILABLE)
                except urllib2.URLError, e:
                    # Is this a temporary network glitch or something a bit
                    # more severe?
                    if isinstance(e.reason, socket.error) and \
                        e.reason.args[0] in temp_net_errors:
                        log.warning(e)
                    else:
                        log.error(e)
                        raise ExitSlave(EX_UNAVAILABLE)
            except ExitSlave, e:
                return e.exit_code
            if self.no_loop:
                break
            time.sleep(self.poll_interval)

    def quit(self):
        log.info('Shutting down')
        raise ExitSlave(EX_OK)

    def _create_build(self, url):
        xml = xmlio.Element('slave', name=self.name, version=PROTOCOL_VERSION)[
            xmlio.Element('platform', processor=self.config['processor'])[
                self.config['machine']
            ],
            xmlio.Element('os', family=self.config['family'],
                                version=self.config['version'])[
                self.config['os']
            ],
        ]

        log.debug('Configured packages: %s', self.config.packages)
        for package, properties in self.config.packages.items():
            xml.append(xmlio.Element('package', name=package, **properties))

        body = str(xml)
        log.debug('Sending slave configuration: %s', body)
        resp = self.request('POST', url, body, {
            'Content-Length': str(len(body)),
            'Content-Type': 'application/x-bitten+xml'
        })

        if resp.code == 201:
            self._initiate_build(resp.info().get('location'))
            return True
        elif resp.code == 204:
            log.info('No pending builds')
            return False
        else:
            log.error('Unexpected response (%d %s)', resp.code, resp.msg)
            raise ExitSlave(EX_PROTOCOL)

    def _initiate_build(self, build_url):
        log.info('Build pending at %s', build_url)
        try:
            resp = self.request('GET', build_url)
            if resp.code == 200:
                self._execute_build(build_url, resp)
            else:
                log.error('Unexpected response (%d): %s', resp.code, resp.msg)
                self._cancel_build(build_url, exit_code=EX_PROTOCOL)
        except KeyboardInterrupt:
            log.warning('Build interrupted')
            self._cancel_build(build_url)

    def _execute_build(self, build_url, fileobj):
        build_id = build_url and int(build_url.split('/')[-1]) or 0
        xml = xmlio.parse(fileobj)
        basedir = ''
        try:
            if not self.local:
                keepalive_thread = KeepAliveThread(self.opener, build_url,
                                    self.single_build, self.keepalive_interval)
                keepalive_thread.start()
            recipe = Recipe(xml, os.path.join(self.work_dir, self.build_dir), 
                            self.config)
            basedir = recipe.ctxt.basedir
            log.debug('Running build in directory %s' % basedir)
            if not os.path.exists(basedir):
                os.mkdir(basedir)

            for step in recipe:
                try:
                    log.info('Executing build step %r, onerror = %s', step.id, step.onerror)
                    if not self._execute_step(build_url, recipe, step):
                        log.warning('Stopping build due to failure')
                        break
                except Exception, e:
                    log.error('Exception raised processing step %s. Reraising %s', step.id, e)
                    raise
            else:
                log.info('Build completed')
            if self.dry_run:
                self._cancel_build(build_url)
        finally:
            if not self.local:
                keepalive_thread.stop()
            if not self.keep_files and os.path.isdir(basedir):
                log.debug('Removing build directory %s' % basedir)
                _rmtree(basedir)
            if self.single_build:
                log.info('Exiting after single build completed.')
                raise ExitSlave(EX_OK)

    def _execute_step(self, build_url, recipe, step):
        failed = False
        started = int(time.time())
        xml = xmlio.Element('result', step=step.id)
        try:
            for type, category, generator, output in \
                    step.execute(recipe.ctxt):
                if type == Recipe.ERROR:
                    failed = True
                if type == Recipe.REPORT and self.dump_reports:
                    print output
                if type == Recipe.ATTACH:
                    # Attachments are added out-of-band due to major
                    # performance issues with inlined base64 xml content
                    self._attach_file(build_url, recipe, output)
                xml.append(xmlio.Element(type, category=category,
                                         generator=generator)[
                    output
                ])
        except KeyboardInterrupt:
            log.warning('Build interrupted')
            self._cancel_build(build_url)
        except BuildError, e:
            log.error('Build step %r failed', step.id)
            failed = True
        except Exception, e:
            log.error('Internal error in build step %r', step.id, exc_info=True)
            failed = True
        xml.attr['duration'] = (time.time() - started)
        if failed:
            xml.attr['status'] = 'failure'
        else:
            xml.attr['status'] = 'success'
            log.info('Build step %s completed successfully', step.id)

        if not self.local and not self.dry_run:
            try:
                resp = self.request('POST', build_url + '/steps/', str(xml), {
                    'Content-Type': 'application/x-bitten+xml'
                })
                if resp.code != 201:
                    log.error('Unexpected response (%d): %s', resp.code,
                              resp.msg)
            except KeyboardInterrupt:
                log.warning('Build interrupted')
                self._cancel_build(build_url)
        return not failed or step.onerror != 'fail'

    def _cancel_build(self, build_url, exit_code=EX_OK):
        log.info('Cancelling build at %s', build_url)
        if not self.local:
            resp = self.request('DELETE', build_url)
            if resp.code not in (200, 204):
                log.error('Unexpected response (%d): %s', resp.code, resp.msg)
        raise ExitSlave(exit_code)

    def _attach_file(self, build_url, recipe, attachment):
        form_token = recipe._root.attr.get('form_token', '')
        if self.local or self.dry_run or not form_token:
            log.info('Attachment %s not sent due to current slave options',
                        attachment.attr['filename'])
            return
        resource_type = attachment.attr['resource']
        url = str(build_url + '/attach/' + resource_type)
        path = recipe.ctxt.resolve(attachment.attr['filename'])
        filename = os.path.basename(path)
        log.debug('Attaching file %s to %s...', attachment.attr['filename'],
                                                    resource_type)
        f = open(path, 'rb')
        try:
            data, content_type = encode_multipart_formdata({
                                'file': (filename, f.read()),
                                'description': attachment.attr['description'],
                                '__FORM_TOKEN': form_token})
        finally:
            f.close()
        resp = self.request('POST', url , data, {
                                'Content-Type': content_type})
        if not resp.code == 201:
            msg = 'Error attaching %s to %s'
            log.error(msg, filename, resource_type)
            raise BuildError(msg, filename, resource_type)

class ExitSlave(Exception):
    """Exception used internally by the slave to signal that the slave process
    should be stopped.
    """
    def __init__(self, exit_code):
        self.exit_code = exit_code
        Exception.__init__(self)


def main():
    """Main entry point for running the build slave."""
    from bitten import __version__ as VERSION
    from optparse import OptionParser

    parser = OptionParser(usage='usage: %prog [options] url1 [url2] ...',
                          version='%%prog %s' % VERSION)
    parser.add_option('--name', action='store', dest='name',
                      help='name of this slave (defaults to host name)')
    parser.add_option('-f', '--config', action='store', dest='config',
                      metavar='FILE', help='path to configuration file')
    parser.add_option('-u', '--user', dest='username',
                      help='the username to use for authentication')
    parser.add_option('-p', '--password', dest='password',
                      help='the password to use when authenticating')
    def _ask_password(option, opt_str, value, parser):
        from getpass import getpass
        parser.values.password = getpass('Passsword: ')
    parser.add_option('-P', '--ask-password', action='callback',
                      callback=_ask_password, help='Prompt for password')
    parser.add_option('--form-auth', action='store_true', 
                      dest='form_auth',
                      help='login using AccountManager HTML form instead of '
                           'HTTP authentication for all urls')

    group = parser.add_option_group('building')
    group.add_option('-d', '--work-dir', action='store', dest='work_dir',
                     metavar='DIR', help='working directory for builds')
    group.add_option('--build-dir', action='store', dest='build_dir',
                     default = 'build_${config}_${build}',
                     help='name pattern for the build dir to use inside the '
                          'working dir ["%default"]')
    group.add_option('-k', '--keep-files', action='store_true',
                     dest='keep_files', 
                     help='don\'t delete files after builds')
    group.add_option('-s', '--single', action='store_true',
                     dest='single_build',
                     help='exit after completing a single build')
    group.add_option('', '--no-loop', action='store_true',
                     dest='no_loop',
                     help='exit after completing a single check and running '
                          'the required builds')
    group.add_option('-n', '--dry-run', action='store_true', dest='dry_run',
                     help='don\'t report results back to master')
    group.add_option('-i', '--interval', dest='interval', metavar='SECONDS',
                     type='int', help='time to wait between requesting builds')
    group.add_option('-b', '--keepalive_interval', dest='keepalive_interval', metavar='SECONDS', type='int', help='time to wait between keepalive heartbeats')
    group = parser.add_option_group('logging')
    group.add_option('-l', '--log', dest='logfile', metavar='FILENAME',
                     help='write log messages to FILENAME')
    group.add_option('-v', '--verbose', action='store_const', dest='loglevel',
                     const=logging.DEBUG, help='print as much as possible')
    group.add_option('-q', '--quiet', action='store_const', dest='loglevel',
                     const=logging.WARN, help='print as little as possible')
    group.add_option('--dump-reports', action='store_true', dest='dump_reports',
                     help='whether report data should be printed')

    parser.set_defaults(dry_run=False, keep_files=False,
                        loglevel=logging.INFO, single_build=False, no_loop=False,
                        dump_reports=False, interval=300, keepalive_interval=60,
                        form_auth=False)
    options, args = parser.parse_args()

    if len(args) < 1:
        parser.error('incorrect number of arguments')
    urls = args

    logger = logging.getLogger('bitten')
    logger.setLevel(options.loglevel)
    handler = logging.StreamHandler()
    handler.setLevel(options.loglevel)
    formatter = logging.Formatter('[%(levelname)-8s] %(message)s')
    handler.setFormatter(formatter)
    logger.addHandler(handler)
    if options.logfile:
        handler = logging.FileHandler(options.logfile)
        handler.setLevel(options.loglevel)
        formatter = logging.Formatter('%(asctime)s [%(name)s] %(levelname)s: '
                                      '%(message)s')
        handler.setFormatter(formatter)
        logger.addHandler(handler)

    log.info("Slave launched at %s" % \
                datetime.now().strftime('%Y-%m-%d %H:%M:%S'))

    slave = None
    try:
        slave = BuildSlave(urls, name=options.name, config=options.config,
                       dry_run=options.dry_run, work_dir=options.work_dir,
                       build_dir=options.build_dir,
                       keep_files=options.keep_files,
                       single_build=options.single_build,
                       no_loop=options.no_loop,
                       poll_interval=options.interval,
                       keepalive_interval=options.keepalive_interval,
                       username=options.username, password=options.password,
                       dump_reports=options.dump_reports,
                       form_auth=options.form_auth)
        try:
            exit_code = slave.run()
        except KeyboardInterrupt:
            slave.quit()
    except ConfigFileNotFound, e:
        log.error(e)
        exit_code = EX_IOERR
    except MissingSectionHeaderError:
        log.error("Error parsing configuration file %r. Wrong format?" \
                            % options.config)
        exit_code = EX_IOERR
    except ExitSlave, e:
        exit_code = e.exit_code

    if slave and not (options.work_dir or options.keep_files):
        log.debug('Removing working directory %s' % slave.work_dir)
        _rmtree(slave.work_dir)

    log.info("Slave exited at %s" % \
                datetime.now().strftime('%Y-%m-%d %H:%M:%S'))

    return exit_code

if __name__ == '__main__':
    sys.exit(main())