kube-glance

#!/usr/bin/python2.7 -u

#
# IMPORTS
#
import ansi
import json
import os
import re
import subprocess
import sys
import time
from argparse import ArgumentParser


#
# CONSTANTS
#
FMT='%20s %10s %10s %15s'


#
# MAIN
#
def main():
  parser = ArgumentParser(description='Get the state of a GKE cluster, at a glance')
  parser.add_argument('--cluster', default='cluster-1', help='What cluster')
  parser.add_argument('--project', default=None, help='Google project')
  args = parser.parse_args()

  if args.project is None:
    print >>sys.stderr, '--project is required'
    sys.exit(1)

  subprocess.check_call('gcloud --project %s container clusters get-credentials %s' % (args.project, args.cluster), shell=True)

  out = subprocess.check_output('kubectl get hpa -o json', shell=True)
  hpas = json.loads(out)

  out = subprocess.check_output('kubectl get deployments -o json', shell=True)
  depls = json.loads(out)

  print ansi.format(FMT % ('app', 'desired', 'available', 'maxReplicas'), ['white', 'bold'])

  for item in depls['items']:
    name = item['metadata']['name']
    app = item['metadata']['labels'].get('app')
    if not app:
      raise StandardError('deployment %s has no "app" label?' % name)

    desired = item['status']['replicas']
    available = item['status'].get('availableReplicas', 0)
    maxReplicas = None

    for hpa in hpas['items']:
      if hpa['spec']['scaleTargetRef']['name'] == name:
        maxReplicas = hpa['spec']['maxReplicas']
        break

    color = 'green'
    if available == 0:  # no replicas!
      color = 'red'
    elif available < desired:  # possible failure to scale up
      color = 'yellow'
    elif (maxReplicas) and (desired == maxReplicas):  # has reached maxReplicas
      color = 'yellow'

    if maxReplicas:
      print ansi.format(FMT % (app, str(desired), str(available), str(maxReplicas)) , [color, 'bold'])
    else:
      print ansi.format(FMT % (app, str(desired), str(available), '-') , [color, 'bold'])

if __name__ == '__main__':
  main()