From b09e878a21c09d8344ec8b2a896d7d1a8162387e Mon Sep 17 00:00:00 2001
From: Magnus Ahltorp <map@kth.se>
Date: Fri, 30 Jun 2017 11:01:52 +0200
Subject: Verify config files against schema

---
 tools/readconfig.py | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 2 deletions(-)

(limited to 'tools/readconfig.py')

diff --git a/tools/readconfig.py b/tools/readconfig.py
index 028e319..15b9c61 100644
--- a/tools/readconfig.py
+++ b/tools/readconfig.py
@@ -50,14 +50,81 @@ def verify_config(rawconfig, signature, publickey_base64, filename):
 
     return errorhandlify(yaml.load(io.BytesIO(rawconfig), yaml.SafeLoader), filename)
 
-def verify_and_read_config(filename, publickey_base64):
+def verify_and_read_config(filename, publickey_base64, schema=None):
     rawconfig = open(filename).read()
     signature = open(filename + ".sig").read()
 
     verify_config(rawconfig, signature, publickey_base64, filename)
     config = yaml.load(io.BytesIO(rawconfig), yaml.SafeLoader)
+    if schema:
+        check_config_schema(config, schema)
     return errorhandlify(config, filename)
 
-def read_config(filename):
+def insert_schema_path(schema, path, datatype, highleveldatatype):
+    if len(path) == 1:
+        schema[path[0]] = (datatype, highleveldatatype)
+    else:
+        if path[0] not in schema:
+            schema[path[0]] = {}
+        insert_schema_path(schema[path[0]], path[1:], datatype, highleveldatatype)
+
+def transform_schema(in_schema):
+    schema = {}
+    for (rawpath, datatype, highleveldatatype) in in_schema:
+        path = rawpath.split("/")
+        insert_schema_path(schema, path, datatype, highleveldatatype)
+    return schema
+
+def check_config_schema(config, schema):
+    transformed_schema = transform_schema(schema)
+    error = check_config_schema_part(config, transformed_schema)
+    if error:
+        print >>sys.stderr, "error:", error
+        sys.exit(1)
+
+def check_config_schema_part(term, schema, path=[]):
+    joined_path = render_path(path)
+    if isinstance(term, basestring):
+        (schema_lowlevel, schema_highlevel) = schema
+        if schema_lowlevel != "string":
+            return "expected %s at %s, not a string" % (schema_lowlevel, joined_path,)
+        return None
+    elif isinstance(term, int):
+        (schema_lowlevel, schema_highlevel) = schema
+        if schema_lowlevel != "integer":
+            return "expected %s at %s, not an integer" % (schema_lowlevel, joined_path,)
+        return None
+    elif isinstance(term, dict):
+        if not isinstance(schema, dict):
+            return "expected %s at %s, not a key" % (schema, joined_path,)
+        for k, v in term.items():
+            schema_part = schema.get(k)
+            if schema_part == None and len(schema.keys()) == 1 and schema.keys()[0].startswith("*"):
+                schema_part = schema[schema.keys()[0]]
+            if schema_part == None:
+                return "configuration key '%s' at %s unknown" % (k, joined_path)
+            result = check_config_schema_part(v, schema_part, path + [k])
+            if result:
+                return result
+        return None
+    elif isinstance(term, list):
+        if not isinstance(schema, dict):
+            return "expected %s at %s, not a list" % (schema, joined_path,)
+        schema_part = schema.get("[]")
+        if schema_part == None:
+            return "expected dict at %s, not a list" % (joined_path,)
+        for i, e in enumerate(term, start=1):
+            result = check_config_schema_part(e, schema_part, path + ["item %d" % i])
+            if result:
+                return result
+        return None
+    else:
+        print >>sys.stderr, "unknown type", type(term)
+        sys.exit(1)
+
+
+def read_config(filename, schema=None):
     config = yaml.load(open(filename), yaml.SafeLoader)
+    if schema:
+        check_config_schema(config, schema)
     return errorhandlify(config, filename)
-- 
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