notebooks/dockeringMongo.py

   1 import docker
   2
   3 #We can run a mongo database server in a container using the following command:
   4 #
   5 ##sudo docker run \
   6 ##  -P -name rs1_srv1 \
   7 ##  -d dev24/mongodb \
   8 ##  --replSet rs1 \
   9 ##  --noprealloc --smallfiles
  10 #
  11 #The -P flag is a docker flag, the rest are passed through the mongodb server)
  12 #That is, the following command is run to start each mongo server using a configuration to keep it small for now...:
  13 # usr/bin/mongod --replSet REPLICA_SET_NAME --noprealloc --smallfiles
  14 #Add a -v flag to command to specify verbose stdio logging (increase the number of v's for more... eg -vv or -vvvv)
  15
  16 def createReplicaSetNode(c,stub,num=0):
  17     ''' Create and run a specified number of mongo database servers as a replica set '''
  18     name='{stub}_srv{num}'.format(stub=stub,num=num)
  19     command='--replSet {stub}  --noprealloc --smallfiles'.format(stub=stub)
  20     c.create_container('dev24/mongodb',name=name,command=command)
  21     c.start(name,publish_all_ports=True)
  22     return name
  23
  24 #Some helper functions via https://github.com/docker/docker-py
  25
  26 #Equivalent of docker ps
  27 def docker_ps(c):
  28     return c.containers(quiet=False, all=False, trunc=True, latest=False, since=None, before=None, limit=-1)
  29
  30
  31 #Find the local port bound for 27017/tcp for each server in the replica set
  32 def get27017tcp_port(c,container):
  33     cConfig = c.inspect_container(container)
  34     return int(cConfig['NetworkSettings']['Ports']['27017/tcp'][0]['HostPort'])
  35
  36 def get27017tcp_ports(c,containers):
  37     ports={}
  38     for container in containers:
  39         ports[container]= get27017tcp_port(c,container)
  40     return ports
  41
  42
  43 def getContainIPaddress(c,container):
  44     cConfig = c.inspect_container(container)
  45     return cConfig['NetworkSettings']['IPAddress']
  46
  47 def getContainIPaddresses(c,containers):
  48     ipaddresses={}
  49     for container in containers:
  50         ipaddresses[container]= getContainIPaddress(c,container)
  51     return ipaddresses
  52
  53
  54 def showContainers(c):
  55     for xc in c.containers(quiet=False, all=False, trunc=True, latest=False, since=None,
  56              before=None, limit=-1):
  57         print(xc['Names'],xc['Status'])
  58
  59
  60 #Helper routines for shutting down and removing containers
  61 def tidyAwayContainer(c,container):
  62     container=container.strip('/')
  63     c.stop(container)
  64     c.remove_container(container)
  65
  66 def tidyAwayContainers(c,containers):
  67     for container in containers:
  68         tidyAwayContainer(c,container)
  69
  70
  71 #Let's create a function that will create several nodes
  72 def createReplicaSetNodes(c,stub,numNodes):
  73     ''' Create and run a specified number of mongo database servers as a replica set '''
  74     names=[]
  75     for i in range(0,numNodes):
  76         name=createReplicaSetNode(c,stub,i)
  77         names.append(name)
  78     return names
  79
  80
  81 def rs_config(c,rsid,num=3):
  82     ''' Create a replica set of nodes and then define a configuation file for that replica set '''
  83     createReplicaSetNodes(c,rsid,num)
  84     _rs_config={"_id" : rsid, 'members':[] }
  85     #This is scrappy - should really return something better from the creation
  86     for i in range(0,num):
  87         name='{stub}_srv{num}'.format(stub=rsid,num=i)
  88         #c.inspect_container(name)
  89         #get IP and port
  90         _rs_config['members'].append({"_id":i,"host":'{0}:{1}'.format(getContainIPaddress(c,name),27017)})
  91     return _rs_config
  92
  93
  94
  95 #Mongo commands
  96 def statusReport(client):
  97     report=client.admin.command("replSetGetStatus")
  98     for m in report['members']:
  99         if 'self' in m and (m['self']):
 100             txt="I am machine id {id} as {state}".format(id=m['_id'],state=m['stateStr'])
 101         else:
 102             txt='Machine id {id} ({state}) last heard from at {time}'.format(id=m['_id'],state=m['stateStr'],time=m['lastHeartbeat'].strftime("%Y-%m-%d %H:%M:%S"))
 103         print(txt)
 104
 105 def memberIPaddress(rs,name):
 106     for host in rs['members']:
 107         if host['_id']==int(name.split('_srv')[1]):
 108             return host['host']