feat: add mongo safe batch delete (#1577)

lualib/skynet/db/mongo.lua

@@ -423,6 +423,18 @@ function mongo_collection:safe_delete(selector, single)
 	return werror(r)
 end
 
+function mongo_collection:safe_batch_delete(selectors, single)
+	local delete_tb = {}
+	for i = 1, #selectors do
+		delete_tb[i] = bson_encode({
+			q = selectors[i],
+			limit = single and 1 or 0,
+		})
+	end
+	local r = self.database:runCommand("delete", self.name, "deletes", delete_tb)
+	return werror(r)
+end
+
 function mongo_collection:findOne(query, selector)
 	local conn = self.connection
 	local request_id = conn:genId()

test/testmongodb.lua

@@ -186,6 +186,32 @@ local function test_safe_batch_insert()
 	assert(length == ret:count(), "test safe batch insert failed")
 end
 
+local function test_safe_batch_delete()
+	local ok, err, ret
+	local c = _create_client()
+	local db = c[db_name]
+
+	db.testcoll:drop()
+
+	local docs, length = {}, 10
+	for i = 1, length do
+		table.insert(docs, {test_key = i})
+	end
+
+	db.testcoll:safe_batch_insert(docs)
+
+	docs = {}
+	local del_num = 5
+	for i = 1, del_num do
+		table.insert(docs, {test_key = i})
+	end
+
+	db.testcoll:safe_batch_delete(docs)
+
+	local ret = db.testcoll:find()
+	assert(length == ret:count(), "test safe batch delete failed")
+end
+
 skynet.start(function()
 	if username then
 		print("Test auth")
@@ -203,5 +229,7 @@ skynet.start(function()
 	test_expire_index()
 	print("test safe batch insert")
 	test_safe_batch_insert()
+	print("test safe batch delete")
+	test_safe_batch_delete()
 	print("mongodb test finish.");
 end)