From 5632852890803561e9d22d69946813975f70b02e Mon Sep 17 00:00:00 2001
From: Matej Ferencevic <matej.ferencevic@memgraph.io>
Date: Tue, 17 Mar 2020 11:06:43 +0100
Subject: [PATCH] Reduce number of errors in production log

Summary:
Currently, when starting Memgraph with the production package (DEB/RPM),
Memgraph always outputs an error for not being able to replace an existing
query module (`example.so` with `example.c`). This diff introduces a precheck
so that the error message is correct - so that Memgraph doesn't try to replace
an `.so` file with a `.c` file before verifying that the `.c` file is a valid
query module (which it obviously isn't). Also, I have moved the source of the
example into a subdirectory so that it isn't even considered while loading
modules.

Reviewers: teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2724
---
 query_modules/CMakeLists.txt   | 2 +-
 src/query/procedure/module.cpp | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/query_modules/CMakeLists.txt b/query_modules/CMakeLists.txt
index 022eb8710..7a474a66a 100644
--- a/query_modules/CMakeLists.txt
+++ b/query_modules/CMakeLists.txt
@@ -25,7 +25,7 @@ install(PROGRAMS $<TARGET_FILE:example>
         DESTINATION lib/memgraph/query_modules
         RENAME example.so)
 # Also install the source of the example, so user can read it.
-install(FILES example.c DESTINATION lib/memgraph/query_modules)
+install(FILES example.c DESTINATION lib/memgraph/query_modules/src)
 
 # Install the Python example
 install(FILES example.py DESTINATION lib/memgraph/query_modules RENAME py_example.py)
diff --git a/src/query/procedure/module.cpp b/src/query/procedure/module.cpp
index 4d0ed6772..899517f41 100644
--- a/src/query/procedure/module.cpp
+++ b/src/query/procedure/module.cpp
@@ -403,6 +403,10 @@ ModuleRegistry::ModuleRegistry() {
 bool ModuleRegistry::LoadModuleLibrary(std::filesystem::path path) {
   std::unique_lock<utils::RWLock> guard(lock_);
   std::string module_name(path.stem());
+  if (path.extension() != ".so" && path.extension() != ".py") {
+    LOG(WARNING) << "Unknown query module file " << path;
+    return false;
+  }
   if (modules_.find(module_name) != modules_.end()) {
     LOG(ERROR) << "Unable to overwrite an already loaded module " << path;
     return false;
@@ -418,7 +422,8 @@ bool ModuleRegistry::LoadModuleLibrary(std::filesystem::path path) {
     if (!loaded) return false;
     modules_[module_name] = std::move(module);
   } else {
-    LOG(ERROR) << "Unknown query module file " << path;
+    LOG(FATAL) << "Unknown query module extension '" << path.extension()
+               << "' from file " << path;
     return false;
   }
   return true;