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Viewing changes to charmhelpers/contrib/openstack/context.py

  • Committer: james.page at ubuntu
  • Date: 2017-04-26 09:48:47 UTC
  • mfrom: (737.1.3 fix-wsgi-workers)
  • Revision ID: james.page@ubuntu.com-20170426094847-cyehqgpxlv9i91rl
Refactor worker multiplier code.

Ensure WSGI processes are capped by default when running in containers.

Skew public processes in favour of admin processes.

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Lines of Context:
charmhelpers/contrib/openstack/context.py
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DEFAULT_MULTIPLIER = 2
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def _calculate_workers():
 
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    '''
 
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    Determine the number of worker processes based on the CPU
 
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    count of the unit containing the application.
 
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    Workers will be limited to MAX_DEFAULT_WORKERS in
 
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    container environments where no worker-multipler configuration
 
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    option been set.
 
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    @returns int: number of worker processes to use
 
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    '''
 
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    multiplier = config('worker-multiplier') or DEFAULT_MULTIPLIER
 
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    count = int(_num_cpus() * multiplier)
 
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    if multiplier > 0 and count == 0:
 
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        count = 1
 
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    if config('worker-multiplier') is None and is_container():
 
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        # NOTE(jamespage): Limit unconfigured worker-multiplier
 
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        #                  to MAX_DEFAULT_WORKERS to avoid insane
 
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        #                  worker configuration in LXD containers
 
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        #                  on large servers
 
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        # Reference: https://pad.lv/1665270
 
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        count = min(count, MAX_DEFAULT_WORKERS)
 
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    return count
 
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def _num_cpus():
 
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    '''
 
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    Compatibility wrapper for calculating the number of CPU's
 
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    a unit has.
 
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    @returns: int: number of CPU cores detected
 
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    '''
 
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    try:
 
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        return psutil.cpu_count()
 
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    except AttributeError:
 
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        return psutil.NUM_CPUS
 
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class WorkerConfigContext(OSContextGenerator):
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    @property
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    def num_cpus(self):
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        # NOTE: use cpu_count if present (16.04 support)
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        if hasattr(psutil, 'cpu_count'):
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            return psutil.cpu_count()
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        else:
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            return psutil.NUM_CPUS
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    def __call__(self):
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        multiplier = config('worker-multiplier') or DEFAULT_MULTIPLIER
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        count = int(self.num_cpus * multiplier)
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        if multiplier > 0 and count == 0:
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            count = 1
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        if config('worker-multiplier') is None and is_container():
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            # NOTE(jamespage): Limit unconfigured worker-multiplier
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            #                  to MAX_DEFAULT_WORKERS to avoid insane
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            #                  worker configuration in LXD containers
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            #                  on large servers
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            # Reference: https://pad.lv/1665270
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            count = min(count, MAX_DEFAULT_WORKERS)
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        ctxt = {"workers": count}
 
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        ctxt = {"workers": _calculate_workers()}
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        return ctxt
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    def __init__(self, name=None, script=None, admin_script=None,
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                 public_script=None, process_weight=1.00,
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                 admin_process_weight=0.75, public_process_weight=0.25):
 
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                 admin_process_weight=0.25, public_process_weight=0.75):
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        self.service_name = name
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        self.user = name
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        self.group = name
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        self.public_process_weight = public_process_weight
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    def __call__(self):
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        multiplier = config('worker-multiplier') or 1
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        total_processes = self.num_cpus * multiplier
 
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        total_processes = _calculate_workers()
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        ctxt = {
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            "service_name": self.service_name,
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            "user": self.user,