Added a tool to search the etcd domain space

This little python script can be used to search for references
to the given domain inside the entire domain space.

tools/search.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python
+"""
+Command line tool for searching the discodns domain space for references to
+a given domain. For example, if you need to find all INCOMING CNAME records to
+the domain foo.bar.net you could use this tool.
+"""
+
+import argparse
+import json
+import requests
+import sys
+
+
+def recurse_nodes(nodes):
+    """Recursively yield all etcd nodes."""
+
+    for node in nodes:
+        yield node
+        for sub_node in recurse_nodes(node.get("nodes", [])):
+            yield sub_node
+
+
+def list_recursive(base, key):
+    url = "%s/%s?recursive=true" % (base, key)
+    response = requests.get(url)
+    if response.status_code >= 200 and response.status_code < 300:
+        content = json.loads(response.text)
+        root_node = content["node"]
+        for node in recurse_nodes(root_node.get("nodes", [])):
+            yield node
+
+
+def format_node(node):
+    return "%s => %s" % (node["key"], node.get("value"))
+
+
+def main(args):
+    parser = argparse.ArgumentParser(prog="search.py", description=__doc__)
+    parser.add_argument("--etcd", default="127.0.0.1:4001",
+                        help="Address for etcd server")
+    parser.add_argument("query", help="Search query")
+
+    args = parser.parse_args()
+    print >> sys.stderr, "[INFO] Searching for domains at %s" % args.etcd
+
+    etcd_keys_base = "http://%s/v2/keys" % args.etcd
+    print >> sys.stderr, "[DEBUG] Using %s as the base for keys" % etcd_keys_base
+    print "-" * 40
+
+    reverse_domain_segments = args.query.split(".")[::-1]
+
+    # Check for any entries for the domain itself
+    for node in list_recursive(etcd_keys_base, "/".join(reverse_domain_segments)):
+        print format_node(node)
+
+    # Search for any domains which contain the query string
+    for node in list_recursive(etcd_keys_base, "/"):
+        if args.query in node.get("value", ""):
+            print format_node(node)
+
+
+if __name__ == "__main__":
+    main(sys.argv[1:])