Instance model

instance.py

from django.db import models
from django_fsm import FSMIntegerField, transition

class Instance(models.Model):
    # Hardware types definition
    X2_HARDWARE_TYPE  = 'c3.large'
    X4_HARDWARE_TYPE  = 'c3.xlarge'
    X16_HARDWARE_TYPE = 'c3.4xlarge'
    
    HARDWARE_TYPE_CHOICES = (
        (X2_HARDWARE_TYPE, '2 Cores / 2 IPs'),
        (X4_HARDWARE_TYPE, '4 Cores / 4 IPs'),
        (X16_HARDWARE_TYPE, '16 Cores / 8 IPs'),
    )
    
    # Placement regions definition
    EU_IRELAND_PLACEMENT_REGION = 'eu-west-1'
    
    PLACEMENT_REGION_CHOICES = (
        (EU_IRELAND_PLACEMENT_REGION, 'EU (Ireland) Region'),
    )
    
    # Thread priorities definition
    HIGH_THREAD_PRIORITY   = 0
    NORMAL_THREAD_PRIORITY = 1
    LOW_THREAD_PRIORITY    = 2
    THREAD_PRIORITY_CHOICES = (
        (HIGH_THREAD_PRIORITY, 'High'),
        (NORMAL_THREAD_PRIORITY, 'Normal'),
        (LOW_THREAD_PRIORITY, 'Low'),
    )
    
    # States definition
    PENDING_STATE    = 0
    RUNNING_STATE    = 1
    STOPPED_STATE    = 2
    TERMINATED_STATE = 3
    STATE_CHOICES = (
        (PENDING_STATE, 'Pending'),
        (RUNNING_STATE, 'Running'),
        (STOPPED_STATE, 'Stopped'),
        (TERMINATED_STATE, 'Terminated'),
    )
    
    hardware_type = models.CharField(
        max_length=50, 
        choices=HARDWARE_TYPE_CHOICES, 
        default=X2_HARDWARE_TYPE
    )
    
    placement_region = models.CharField(
        max_length=50, 
        choices=PLACEMENT_REGION_CHOICES, 
        default=EU_IRELAND_PLACEMENT_REGION
    )
    
    thread_priority = models.IntegerField(
        max_length=1, 
        choices=THREAD_PRIORITY_CHOICES,
        default=NORMAL_THREAD_PRIORITY
    )
    
    state = FSMIntegerField(
        max_length=1,
        default=PENDING_STATE,
        choices=STATE_CHOICES,
        protected=True
    )
    
    image        = models.CharField(max_length=50)
    access_token = models.CharField(max_length=50)
    created_at   = models.DateTimeField(auto_now_add=True)
    updated_at   = models.DateTimeField(auto_now=True)