Add instance-type-comment script

Signed-off-by: Knut Ahlers <knut@ahlers.me>

bin/instance-type-comment.py

@@ -0,0 +1,104 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright:
+#   2017 Knut Ahlers <github.com/Luzifer>
+# License:
+#   Apache v2.0
+#   https://www.apache.org/licenses/LICENSE-2.0.html
+
+from __future__ import print_function
+
+# included
+import json
+import os
+import sys
+import time
+
+# external requirement
+import requests
+
+SOURCE_FILE = 'https://ec2instances.info/instances.json'
+CACHE_TIME = 7 * 24 * 3600
+CACHE_FILE = os.path.expanduser('~/.local/share/itc/instances.json')
+REGION_FALLBACK = 'eu-west-1'
+
+
+def beautify_ecu(ecu):
+    if ecu == 'variable':
+        return 'var'
+    return str(ecu).strip('.0')
+
+
+def beautify_mem(mem):
+    return str(mem).strip('.0')
+
+
+def get_region():
+    if 'AWS_REGION' in os.environ:
+        return os.environ['AWS_REGION']
+    if 'AWS_DEFAULT_REGION' in os.environ:
+        return os.environ['AWS_DEFAULT_REGION']
+    return REGION_FALLBACK
+
+
+def monthly_pricing(hourly_rate):
+    price = float(hourly_rate) * 24 * 365 / 12
+    return round(price)
+
+
+def renew_cache():
+    least_mod_time = time.time() - CACHE_TIME
+    if os.path.isfile(CACHE_FILE) and os.path.getmtime(CACHE_FILE) > least_mod_time:
+        return
+
+    try:
+        os.makedirs(os.path.dirname(CACHE_FILE))
+    except OSError:
+        # Creating an existing directory will fail which is okay
+        pass
+
+    with open(CACHE_FILE, 'w') as cf:
+        cf.write(requests.get(SOURCE_FILE).text)
+
+    return
+
+
+def generate_comment(instance_type):
+    renew_cache()
+    region = get_region()
+
+    instances = json.loads(open(CACHE_FILE, 'r').read())
+    for instance in instances:
+        if instance['instance_type'] != instance_type:
+            continue
+
+        if region not in instance['pricing']:
+            print('Region "{}" is unknown in pricing table.'.format(region))
+            return None
+
+        return '{vcpu} ({ecu}) / {mem} / {network} / ${price:.0f}'.format(
+            vcpu=instance['vCPU'],
+            ecu=beautify_ecu(instance['ECU']),
+            mem=beautify_mem(instance['memory']),
+            network=instance['network_performance'],
+            price=monthly_pricing(
+                instance['pricing'][region]['linux']['ondemand']),
+        )
+
+
+def main(args):
+    comment = generate_comment(args[1])
+    if comment is None:
+        return 1
+
+    print('      InstanceTypeComment: {}'.format(comment))
+    return 0
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print(
+            'Please supply an instance type to format: e.g. {} m4.large'.format(sys.argv[0]))
+        sys.exit(1)
+    sys.exit(main(sys.argv))