create federated files from input yaml

README.md

this is a simple tool called federer.py which, for a given yaml file:

• splits its multiple documents
• create the corresponding federated and placement files
• indicate which types will be required
• a script to actually deploys

The tool has also won 20 grand slams

federer.py

#!/usr/bin/env python

import os
import sys
import yaml

if len(sys.argv) != 2:
    print("Usage: federer.py file")
    sys.exit(1)
elif not os.path.exists(sys.argv[1]):
    print("Input file not found")
    sys.exit(1)
else:
    inputfile = sys.argv[1]

results = []
data = ""

delimiter = False
inputlines = open(inputfile).readlines()
for index, line in enumerate(inputlines):
    if (line.startswith('---') and index != 0) or index == len(inputlines) - 1:
        delimiter = True
        results.append(data)
        data = ""
    else:
        data += line

if not delimiter:
    data = open(inputfile).read()
    results = [data]

federatedresources = []
federatedplacements = []
federatedtypes = []
customresources = []
for r in results:
    try:
        data = yaml.load(r)
    except Exception as e:
        print("Failed to parse input file. Got %s" % e)
    name, kind = data['metadata']['name'].replace(':', '.'), data['kind']
    print("Processing %s %s" % (kind, name))
    placement = {'kind': 'Federated%sPlacement' % kind, 'spec': {'clusterNames': ['cluster1', 'cluster2']},
                 'metadata': {'name': name}}
    if 'namespace' in data['metadata']:
        placement['metadata']['namespace'] = data['metadata']['namespace']
    if data['kind'] == 'Namespace':
        continue
    if data['kind'] not in federatedtypes and data['kind'] != 'Namespace':
        federatedtypes.append(data['kind'])
    if data['kind'] == 'CustomResourceDefinition':
        customname = name.split('.')[0]
        customresources.append(customname)
    newdata = {'metadata': {'name': name}}
    if 'namespace' in data['metadata']:
        newdata['metadata']['namespace'] = data['metadata']['namespace']
    newdata['kind'] = "Federated%s" % data['kind']
    newdata['apiVersion'] = "primitives.federation.k8s.io/v1alpha1"
    spec = {k: data[k] for k in data if k not in ['kind', 'apiVersion', 'metadata']}
    newdata['spec'] = {'template': spec}
    if data['kind'] == 'Deployment':
        labels = data['spec']['template']['metadata']['labels']
        newdata['metadata']['labels'] = labels
        newdata['spec']['template']['spec']['selector'] = {'matchLabels': labels}
    placement['apiVersion'] = "primitives.federation.k8s.io/v1alpha1"
    federatedresources.append([newdata, placement])


Dumper = yaml.dumper.SafeDumper
Dumper.ignore_aliases = lambda self, data: True
with open("federated_%s" % inputfile, 'w') as f:
    for entry in federatedresources:
        resource, placement = entry
        if resource is not None:
            output = yaml.dump(resource, default_flow_style=False, indent=2, allow_unicode=True,
                               encoding=None, Dumper=Dumper)[:-1]
            f.write(output)
            f.write('\n---\n')
        output = yaml.dump(placement, default_flow_style=False, indent=2, allow_unicode=True,
                           encoding=None, Dumper=Dumper)[:-1]
        f.write(output)
        f.write('\n---\n')
    print("federated_%s created" % inputfile)

with open("federated_%s.sh" % inputfile, 'w') as f:
    print("federated_%s.sh created" % inputfile)
    for _type in sorted(federatedtypes):
        f.write("kubefed2 enable %s\n" % (_type))
    f.write("kubectl create -f federated_%s\n" % inputfile)
    for _type in sorted(customresources):
        f.write("kubefed2 enable %s\n" % (_type))

sys.exit(0)