1 files changed, 74 insertions, 0 deletions
diff --git a/filter_plugins/dns.py b/filter_plugins/dns.py
new file mode 100644
index 0000000..9fdca29
--- /dev/null
+++ b/filter_plugins/dns.py
@@ -0,0 +1,74 @@
+# Credit: https://github.com/kgaughan/zones
+
+"""
+Custom Ansible template filters for DNS management.
+"""
+
+import os
+import datetime
+import random
+import shlex
+import subprocess
+
+
+def which(cmd):
+    for path in os.environ["PATH"].split(os.pathsep):
+        full_path = os.path.join(path, cmd)
+        if os.access(full_path, os.X_OK):
+            return full_path
+    return None
+
+
+def run_query(cmd, rtype, fqdn, ns=None):
+    if not fqdn.endswith("."):
+        fqdn += "."
+    args = [cmd, fqdn, rtype]
+    if ns:
+        args.append("@" + ns)
+
+    output = subprocess.check_output(args, universal_newlines=True)
+    for line in output.split("\n"):
+        if line.startswith(";"):
+            continue
+        parsed = shlex.split(line)
+        if len(parsed) > 0 and parsed[0] == fqdn and parsed[3] == rtype:
+            yield parsed[4:]
+
+
+def next_serial(fqdn):
+    cmd = "drill"
+    cmd_path = which(cmd)
+    if cmd_path is None:
+        raise Exception("Cannot find %s" % cmd)
+
+    def query_nameservers(fqdn, ns=None):
+        return [line[0] for line in run_query(cmd_path, "NS", fqdn, ns)]
+
+    # Get a registry nameserver.
+    reg_ns = random.choice(query_nameservers(".".join(fqdn.split(".")[1:])))
+
+    nss = query_nameservers(fqdn, reg_ns)
+    random.shuffle(nss)
+
+    current_serial = None
+    for ns in nss:
+        try:
+            for line in run_query(cmd_path, "SOA", fqdn, ns):
+                current_serial = line[2]
+                break
+        except subprocess.CalledProcessError as e:
+            if e.returncode not in [9]:
+                raise
+        if current_serial is not None:
+            break
+
+    today = datetime.datetime.utcnow().strftime("%Y%m%d")
+    if current_serial is None or current_serial[:8] != today:
+        return today + "00"
+    else:
+        return str(int(current_serial) + 1)
+
+
+class FilterModule(object):
+    def filters(self):
+        return {"next_serial": next_serial}