ovsdb-server: Allow OVSDB clients to specify the UUID for inserted rows.

Acked-by: Han Zhou <hzhou@ovn.org>
Requested-by: Leonid Ryzhyk <lryzhyk@vmware.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

Documentation/ref/ovsdb-server.7.rst

@@ -546,6 +546,15 @@ condition can be either a 3-element JSON array as described in the RFC or a
 boolean value. In case of an empty array an implicit true boolean value will be
 considered.
 
+5.2.1 Insert
+------------
+
+As an extension, Open vSwitch 2.13 and later allow an optional ``uuid`` member
+to specify the UUID for the new row.  The specified UUID must be unique within
+the table when it is inserted and not the UUID of a row previously deleted
+within the transaction.  If the UUID violates these rules, then the operation
+fails with a ``duplicate uuid`` error.
+
 5.2.6 Wait, 5.2.7 Commit, 5.2.9 Comment
 ---------------------------------------
 

NEWS

@@ -36,6 +36,7 @@ Post-v2.12.0
        command - ovsdb-server/set-active-ovsdb-server-probe-interval.
      * Add hardware offload support for output, drop, set of MAC, IPv4 and
        TCP/UDP ports actions (experimental).
+     * ovsdb-server: New OVSDB extension to allow clients to specify row UUIDs.
    - 'ovs-appctl dpctl/dump-flows' can now show offloaded=partial for
      partially offloaded flows, dp:dpdk for fully offloaded by dpdk, and
      type filter supports new filters: "dpdk" and "partially-offloaded".

ovsdb/execution.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2017 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2017, 2019 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -329,18 +329,32 @@ ovsdb_execute_insert(struct ovsdb_execution *x, struct ovsdb_parser *parser,
 {
     struct ovsdb_table *table;
     struct ovsdb_row *row = NULL;
-    const struct json *uuid_name, *row_json;
+    const struct json *uuid_json, *uuid_name, *row_json;
     struct ovsdb_error *error;
     struct uuid row_uuid;
 
     table = parse_table(x, parser, "table");
+    uuid_json = ovsdb_parser_member(parser, "uuid", OP_STRING | OP_OPTIONAL);
     uuid_name = ovsdb_parser_member(parser, "uuid-name", OP_ID | OP_OPTIONAL);
     row_json = ovsdb_parser_member(parser, "row", OP_OBJECT);
     error = ovsdb_parser_get_error(parser);
     if (error) {
         return error;
     }
 
+    if (uuid_json) {
+        if (!uuid_from_string(&row_uuid, json_string(uuid_json))) {
+            return ovsdb_syntax_error(uuid_json, NULL, "bad uuid");
+        }
+
+        if (!ovsdb_txn_may_create_row(table, &row_uuid)) {
+            return ovsdb_syntax_error(uuid_json, "duplicate uuid",
+                                      "This UUID would duplicate a UUID "
+                                      "already present within the table or "
+                                      "deleted within the same transaction.");
+        }
+    }
+
     if (uuid_name) {
         struct ovsdb_symbol *symbol;
 
@@ -350,9 +364,13 @@ ovsdb_execute_insert(struct ovsdb_execution *x, struct ovsdb_parser *parser,
                                       "This \"uuid-name\" appeared on an "
                                       "earlier \"insert\" operation.");
         }
-        row_uuid = symbol->uuid;
+        if (uuid_json) {
+            symbol->uuid = row_uuid;
+        } else {
+            row_uuid = symbol->uuid;
+        }
         symbol->created = true;
-    } else {
+    } else if (!uuid_json) {
         uuid_generate(&row_uuid);
     }
 

ovsdb/transaction.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2017 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2017, 2019 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -1287,6 +1287,26 @@ ovsdb_txn_row_delete(struct ovsdb_txn *txn, const struct ovsdb_row *row_)
     }
 }
 
+/* Returns true if 'row_uuid' may be used as the UUID for a newly created row
+ * in 'table' (that is, that it is unique within 'table'), false otherwise. */
+bool
+ovsdb_txn_may_create_row(const struct ovsdb_table *table,
+                         const struct uuid *row_uuid)
+{
+    /* If a row 'row_uuid' currently exists, disallow creating a duplicate. */
+    if (ovsdb_table_get_row(table, row_uuid)) {
+        return false;
+    }
+
+    /* If a row 'row_uuid' previously existed in this transaction, disallow
+     * creating a new row with the same UUID. */
+    if (find_txn_row(table, row_uuid)) {
+        return false;
+    }
+
+    return true;
+}
+
 void
 ovsdb_txn_add_comment(struct ovsdb_txn *txn, const char *s)
 {

ovsdb/transaction.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2017 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2017, 2019 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -53,6 +53,9 @@ struct ovsdb_row *ovsdb_txn_row_modify(struct ovsdb_txn *,
 void ovsdb_txn_row_insert(struct ovsdb_txn *, struct ovsdb_row *);
 void ovsdb_txn_row_delete(struct ovsdb_txn *, const struct ovsdb_row *);
 
+bool ovsdb_txn_may_create_row(const struct ovsdb_table *,
+                              const struct uuid *row_uuid);
+
 typedef bool ovsdb_txn_row_cb_func(const struct ovsdb_row *old,
                                    const struct ovsdb_row *new,
                                    const unsigned long int *changed,

tests/ovsdb-execution.at

@@ -249,6 +249,30 @@ OVSDB_CHECK_EXECUTION([insert row, query table],
 [{"rows":[{"_uuid":["uuid","<0>"],"_version":["uuid","<1>"],"name":"zero","number":0}]}]
 ]])
 
+OVSDB_CHECK_EXECUTION([insert row with uuid, query table],
+  [ordinal_schema],
+dnl Insert initial row.
+  [[[["ordinals",
+      {"op": "insert",
+       "uuid": "ffffffff-971b-4cba-bf42-520515973b7e",
+       "table": "ordinals",
+       "row": {"number": 0, "name": "zero"}}]]],
+dnl Query row back.
+   [[["ordinals",
+      {"op": "select",
+       "table": "ordinals",
+       "where": []}]]],
+dnl Attempt to insert second row with same UUID (fails).
+   [[["ordinals",
+      {"op": "insert",
+       "uuid": "ffffffff-971b-4cba-bf42-520515973b7e",
+       "table": "ordinals",
+       "row": {"number": 0, "name": "zero"}}]]]],
+  [[[{"uuid":["uuid","ffffffff-971b-4cba-bf42-520515973b7e"]}]
+[{"rows":[{"_uuid":["uuid","ffffffff-971b-4cba-bf42-520515973b7e"],"_version":["uuid","<0>"],"name":"zero","number":0}]}]
+[{"details":"This UUID would duplicate a UUID already present within the table or deleted within the same transaction.","error":"duplicate uuid","syntax":"\"ffffffff-971b-4cba-bf42-520515973b7e\""}]
+]])
+
 OVSDB_CHECK_EXECUTION([insert rows, query by value],
   [ordinal_schema],
   [[[["ordinals",

tests/uuidfilt.py

@@ -18,7 +18,8 @@ def sort_set(match):
 
 
 u = '[0-9a-fA-F]'
-uuid_re = re.compile(r'%s{8}-%s{4}-%s{4}-%s{4}-%s{12}' % ((u,) * 5))
+uuid_re = re.compile(r'%s{8}(?<!ffffffff)-%s{4}-%s{4}-%s{4}-%s{12}'
+                     % ((u,) * 5))
 set_re = re.compile(r'(\["set",\[(,?\["uuid","<\d+>"\])+\]\])')
 
 
@@ -43,7 +44,20 @@ def lf(match):
 
 
 if __name__ == '__main__':
-    if len(sys.argv) > 1:
+    if '--help' in sys.argv:
+        print("""\
+uuidfilt, for filtering UUIDs into numbered markers
+usage: %s [INPUT..] > OUTPUT
+    or %s < INPUT > OUTPUT
+
+Reads each INPUT, locates UUIDs in the standard textual form, and
+converts them into numbered markers <0>, <1>, ..., <n>, where <0>
+stands in for each instance of the first unique UUID found, <1> for
+each instance of the second, and so on.
+
+UUIDs that begin with ffffffff are not converted to markers.
+""")
+    elif len(sys.argv) > 1:
         for src in sys.argv[1:]:
             filter_uuids(open(src), sys.stdout)
     else: