Try to set up lua runtime.

.github/workflows/ci.yaml

+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: CI AND IT
+
+on:
+  pull_request:
+  push:
+    branches: 
+      - master
+    tags:
+      - 'v*'
+    
+
+jobs:
+  CI:
+    runs-on: ubuntu-18.04
+    timeout-minutes: 180
+    strategy:
+      fail-fast: true
+    steps:
+      - uses: actions/checkout@v1
+        with:
+          submodules: true
+      - name: 'Install LUA runtime'
+        run: |
+          sh lua-setup.sh
+          lua -v
\ No newline at end of file

ci/lua-setup.sh

+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+curl -R -O http://www.lua.org/ftp/lua-5.3.5.tar.gz
+tar zxf lua-5.3.5.tar.gz
+cd lua-5.3.5
+make linux test
+cd src
+LUA_PATH=`pwd`
+export PATH=$PATH:$LUA_PATH
+echo $PATH
\ No newline at end of file

lib/sw_agent.lua → lib/skywalking/agent.lua

@@ -13,4 +13,5 @@
 -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
--- 
\ No newline at end of file
+-- 
+

lib/skywalking/buffer.lua

+-- 
+-- Licensed to the Apache Software Foundation (ASF) under one or more
+-- contributor license agreements.  See the NOTICE file distributed with
+-- this work for additional information regarding copyright ownership.
+-- The ASF licenses this file to You under the Apache License, Version 2.0
+-- (the "License"); you may not use this file except in compliance with
+-- the License.  You may obtain a copy of the License at
+-- 
+--    http://www.apache.org/licenses/LICENSE-2.0
+-- 
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+-- 
+