Add ability to generate correct hosts file

mandarjog · May 18, 2016 · 559fc56 · 559fc56
1 parent 9e05cfa
commit 559fc56
Showing 1 changed file with 76 additions and 0 deletions.
diff --git a/genhosts.py b/genhosts.py
@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+import socket
+import sys
+import yaml
+from boto3.session import Session
+
+
+def genhosts(elbip, sysdomain, outfile=sys.stdout):
+    SYS_PREFIXES = [
+        'console',
+        'uaa',
+        'apps',
+        'login']
+
+    print >>outfile, "#"*16, "Generated for /etc/hosts by cfawsinit", "#"*16
+
+    print >>outfile, elbip, sysdomain
+    for prefix in SYS_PREFIXES:
+        print >>outfile, elbip, prefix+"."+sysdomain
+    print >>outfile, "#"*16, "Generated for /etc/hosts by cfawsinit", "#"*16
+
+
+def get_elbip(elb, stackname):
+    lbname = stackname + "-pcf-elb"
+    resp = elb.describe_load_balancers(
+        LoadBalancerNames=[lbname])
+    if len(resp.get('LoadBalancerDescriptions', [])) == 0:
+        raise Exception(lbname + " Loadbalacer could not be found")
+    dnsname = resp['LoadBalancerDescriptions'][0]['DNSName']
+    return socket.gethostbyname(dnsname)
+
+
+def get_args():
+    import argparse
+    argp = argparse.ArgumentParser()
+    argp.add_argument('--profile')
+    argp.add_argument('--stack-name')
+    argp.add_argument('--outfile')
+    argp.add_argument('--prepared-cfg')
+    argp.add_argument('--system-domain')
+    argp.add_argument('--region', default='us-east-1')
+    return argp
+
+
+def fix_args(args):
+    if args.prepared_cfg is not None:
+        opts = yaml.load(open(args.prepared_cfg, 'rt'))
+        args.system_domain = args.system_domain or opts["system_domain"]
+        args.stack_name = args.stack_name or opts["stack-name"]
+        args.region = opts["region"]
+
+    if args.outfile is not None:
+        args.outfile = open(args.outfile, "wt")
+
+
+def main(argv):
+    args = get_args().parse_args(argv)
+
+    if args.prepared_cfg is None and\
+            args.system_domain is None:
+                print ("Either --prepared-cfg or "
+                       "(--system-domain and --stack-name) are required")
+                return -1
+    fix_args(args)
+    session = Session(profile_name=args.profile, region_name=args.region)
+    elb = session.client("elb")
+
+    genhosts(
+        get_elbip(elb, args.stack_name),
+        args.system_domain,
+        args.outfile)
+
+
+if __name__ == "__main__":
+    import sys
+    sys.exit(main(sys.argv[1:]))