pytest: test the db hook plugin.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/plugins/dblog.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+"""This plugin is used to check that db_write calls are working correctly.
+"""
+from lightning import Plugin, RpcError
+import sqlite3
+
+plugin = Plugin()
+plugin.sqlite_pre_init_cmds = []
+plugin.initted = False
+
+
+@plugin.init()
+def init(configuration, options, plugin):
+    if not plugin.get_option('dblog-file'):
+        raise RpcError("No dblog-file specified")
+    plugin.conn = sqlite3.connect(plugin.get_option('dblog-file'),
+                                  isolation_level=None)
+    plugin.log("replaying pre-init data:")
+    for c in plugin.sqlite_pre_init_cmds:
+        plugin.conn.execute(c)
+        plugin.log("{}".format(c))
+    plugin.initted = True
+    plugin.log("initialized")
+
+
+@plugin.hook('db_write')
+def db_write(plugin, writes):
+    if not plugin.initted:
+        plugin.log("deferring {} commands".format(len(writes)))
+        plugin.sqlite_pre_init_cmds += writes
+    else:
+        for c in writes:
+            plugin.conn.execute(c)
+            plugin.log("{}".format(c))
+    return True
+
+
+plugin.add_option('dblog-file', None, 'The db file to create.')
+plugin.run()

tests/test_plugin.py

@@ -3,7 +3,9 @@ from fixtures import *  # noqa: F401,F403
 from lightning import RpcError, Millisatoshi
 from utils import only_one
 
+import os
 import pytest
+import sqlite3
 import subprocess
 import time
 
@@ -190,6 +192,31 @@ def test_async_rpcmethod(node_factory, executor):
     assert [r.result() for r in results] == [42] * len(results)
 
 
+def test_db_hook(node_factory, executor):
+    """This tests the db hook."""
+    dbfile = os.path.join(node_factory.directory, "dblog.sqlite3")
+    l1 = node_factory.get_node(options={'plugin': 'tests/plugins/dblog.py',
+                                        'dblog-file': dbfile})
+
+    # It should see the db being created, and sometime later actually get
+    # initted.
+    # This precedes startup, so needle already past
+    assert l1.daemon.is_in_log('plugin-dblog.py deferring 1 commands')
+    l1.daemon.logsearch_start = 0
+    l1.daemon.wait_for_log('plugin-dblog.py replaying pre-init data:')
+    l1.daemon.wait_for_log('plugin-dblog.py PRAGMA foreign_keys = ON;')
+    l1.daemon.wait_for_log('plugin-dblog.py CREATE TABLE version \\(version INTEGER\\)')
+    l1.daemon.wait_for_log('plugin-dblog.py initialized')
+
+    l1.stop()
+
+    # Databases should be identical.
+    db1 = sqlite3.connect(os.path.join(l1.daemon.lightning_dir, 'lightningd.sqlite3'))
+    db2 = sqlite3.connect(dbfile)
+
+    assert [x for x in db1.iterdump()] == [x for x in db2.iterdump()]
+
+
 def test_utf8_passthrough(node_factory, executor):
     l1 = node_factory.get_node(options={'plugin': 'tests/plugins/utf8.py',
                                         'log-level': 'io'})

wallet/db.c

@@ -7,6 +7,7 @@
 #include <inttypes.h>
 #include <lightningd/lightningd.h>
 #include <lightningd/log.h>
+#include <lightningd/plugin_hook.h>
 
 #define DB_FILE "lightningd.sqlite3"
 
@@ -578,13 +579,8 @@ static void db_report_changes(struct db *db, const char *final, size_t min)
 	assert(db->changes);
 	assert(tal_count(db->changes) >= min);
 
-	if (tal_count(db->changes) > min) {
-		fprintf(stderr, "Committing db changes:\n");
-		for (size_t i = 0; i < tal_count(db->changes); i++)
-			fprintf(stderr, "  %zu: %s\n", i, db->changes[i]);
-		if (final)
-			fprintf(stderr, "  %s\n", final);
-	}
+	if (tal_count(db->changes) > min)
+		plugin_hook_db_sync(db, db->changes, final);
 	db->changes = tal_free(db->changes);
 }
 

wallet/test/run-db.c

@@ -37,6 +37,10 @@ static void db_test_fatal(const char *fmt, ...)
 	va_end(ap);
 }
 
+void plugin_hook_db_sync(struct db *db UNNEEDED, const char **changes UNNEEDED, const char *final UNNEEDED)
+{
+}
+
 static struct db *create_test_db(void)
 {
 	struct db *db;

wallet/test/run-wallet.c

@@ -564,6 +564,9 @@ u8 *wire_sync_read(const tal_t *ctx UNNEEDED, int fd UNNEEDED)
 {
 	return NULL;
 }
+void plugin_hook_db_sync(struct db *db UNNEEDED, const char **changes UNNEEDED, const char *final UNNEEDED)
+{
+}
 bool fromwire_hsm_get_channel_basepoints_reply(const void *p UNNEEDED,
 					       struct basepoints *basepoints,
 					       struct pubkey *funding_pubkey)