Merge pull request #13 from crccheck/plumbum

add utility to help me generate config files

Makefile

@@ -24,3 +24,9 @@ test:
 .PHONY: build
 build:
 	python setup.py sdist bdist_wheel upload
+
+
+# makes it easier to test setup.py's entry points
+reinstall:
+	pip uninstall cloudwatch-to-graphite --yes
+	pip install .

config.yaml.j2.example

@@ -0,0 +1,20 @@
+{# This is a Jinja2 comment
+  To use this template, you'd run something like:
+  python plumbum.py config.yaml.j2.example ec2
+ #}
+# Sample config.yaml
+Metrics:
+{% for instance in resources %}
+- Namespace: "AWS/EC2"
+  MetricName: "CPUUtilization"
+  Statistics:
+  - "Maximum"
+  - "Average"
+  Unit: "Percent"
+  Dimensions:
+    InstanceId: "{{ instance.id }}"
+  Options:
+    {# I'm assuming my tag names are safe to use as metric names here #}
+    Formatter: 'cloudwatch.%(Namespace)s.{{ instance.tags['Name'] }}.%(MetricName)s.%(statistic)s.%(Unit)s'
+    Period: 5
+{% endfor %}

plumbum.py

@@ -0,0 +1,114 @@
+# -*- coding: UTF-8 -*-
+"""
+Usage:
+  plumbum <template> <namespace> [options]...
+
+Examples:
+
+  plumbum elb.yaml.j2 elb
+  plumbum ec2.yaml.j2 ec2 environment=production
+
+Outputs to stdout.
+
+"""
+from __future__ import unicode_literals
+
+import sys
+
+import boto.ec2
+import boto.ec2.elb
+import boto.rds
+import jinja2
+
+
+def get_property_func(key):
+    """
+    Get the accessor function for an instance to look for `key`.
+
+    Look for it as an attribute, and if that does not work, look to see if it
+    is a tag.
+    """
+    def get_it(obj):
+        try:
+            return getattr(obj, key)
+        except AttributeError:
+            return obj.tags.get(key)
+    return get_it
+
+
+def filter_key(filter_args):
+    def filter_instance(instance):
+        return all([value == get_property_func(key)(instance)
+            for key, value in filter_args.items()])
+    return filter_instance
+
+
+def lookup(instances, filter_by=None):
+    if filter_by:
+        return filter(filter_key(filter_by), instances)
+    return instances
+
+
+def get_options(input_args):
+    filter_by_kwargs = {}
+    for arg in input_args:
+        if arg.startswith('-'):
+            # ignore options
+            continue
+        if '=' in arg:
+            key, value = arg.split('=', 2)
+            filter_by_kwargs[key] = value
+    return filter_by_kwargs
+
+
+def list_ec2(filter_by_kwargs):
+    conn = boto.ec2.connect_to_region('us-east-1')  # XXX magic constant
+    instances = conn.get_only_instances()
+    return lookup(instances, filter_by=filter_by_kwargs)
+
+
+def list_elb(filter_by_kwargs):
+    conn = boto.ec2.elb.connect_to_region('us-east-1')  # XXX magic constant
+    instances = conn.get_all_load_balancers()
+    return lookup(instances, filter_by=filter_by_kwargs)
+
+
+def list_rds(filter_by_kwargs):
+    conn = boto.rds.connect_to_region('us-east-1')
+    instances = conn.get_all_dbinstances()
+    return lookup(instances, filter_by=filter_by_kwargs)
+
+
+def main():
+    if len(sys.argv) < 3:
+        print __doc__
+        sys.exit()
+    options = sys.argv[1:]
+    template = options[0]
+    namespace = options[1].lower()
+    filters = get_options(options[2:])
+
+    # get the template first so this can fail before making a network request
+    loader = jinja2.FileSystemLoader('.')
+    jinja2_env = jinja2.Environment(loader=loader)
+    template = jinja2_env.get_template(template)
+
+    # should I be using ARNs?
+    if namespace in ('ec2', 'aws/ec2'):
+        resources = list_ec2(filters)
+    elif namespace in ('elb', 'aws/elb'):
+        resources = list_elb(filters)
+    elif namespace in ('rds', 'aws/rds'):
+        resources(filters)
+    else:
+        # TODO
+        sys.exit(1)
+
+    print template.render({
+        'filters': filters,
+        'resources': resources,
+    })
+
+
+if __name__ == '__main__':
+    main()

requirements.txt

@@ -1,6 +1,7 @@
 boto==2.33.0
 PyYAML==3.11
 docopt==0.6.2
+Jinja2==2.7.3
 
 # tests
 tox==1.8.0

setup.py

@@ -8,16 +8,18 @@
     author='Chris Chang',
     author_email='[email protected]',
     url='https://github.com/crccheck/cloudwatch-to-graphite',
-    py_modules=['leadbutt'],
+    py_modules=['leadbutt', 'plumbum'],
     entry_points={
         'console_scripts': [
             'leadbutt = leadbutt:main',
+            'plumbum = plumbum:main',
         ],
     },
     install_requires=[
         'boto',
         'PyYAML',
         'docopt',
+        'Jinja2',
     ],
     license='Apache License, Version 2.0',
     long_description=open('README.rst').read(),