feat(ext-plugin): stop the runner with SIGTERM

Signed-off-by: spacewander <spacewanderlzx@gmail.com>

apisix/cli/ngx_tpl.lua

@@ -289,6 +289,12 @@ http {
         apisix.http_init_worker()
     }
 
+    {% if not use_or_1_17 then %}
+    exit_worker_by_lua_block {
+        apisix.http_exit_worker()
+    }
+    {% end %}
+
     {% if enable_control then %}
     server {
         listen {* control_server_addr *};

apisix/cli/ops.lua

@@ -361,6 +361,11 @@ Please modify "admin_key" in conf/config.yaml .
         util.die("openresty version must >=", need_ver, " current ", or_ver, "\n")
     end
 
+    local use_or_1_17 = false
+    if not check_version(or_ver, "1.19.3") then
+        use_or_1_17 = true
+    end
+
     local or_info = util.execute_cmd("openresty -V 2>&1")
     local with_module_status = true
     if or_info and not or_info:find("http_stub_status_module", 1, true) then
@@ -446,6 +451,7 @@ Please modify "admin_key" in conf/config.yaml .
 
     -- Using template.render
     local sys_conf = {
+        use_or_1_17 = use_or_1_17,
         lua_path = env.pkg_path_org,
         lua_cpath = env.pkg_cpath_org,
         os_name = util.trim(util.execute_cmd("uname")),

apisix/core/os.lua

@@ -23,11 +23,18 @@ local type = type
 
 
 local _M = {}
+local WNOHANG = 1
 
 
 ffi.cdef[[
+    typedef int32_t pid_t;
+    typedef unsigned int  useconds_t;
+
     int setenv(const char *name, const char *value, int overwrite);
     char *strerror(int errnum);
+
+    int usleep(useconds_t usec);
+    pid_t waitpid(pid_t pid, int *wstatus, int options);
 ]]
 
 
@@ -52,4 +59,31 @@ function _M.setenv(name, value)
 end
 
 
+local function waitpid_nohang(pid)
+    local res = C.waitpid(pid, nil, WNOHANG)
+    if res == -1 then
+        return nil, err()
+    end
+    return res > 0
+end
+
+
+function _M.waitpid(pid, timeout)
+    local count = 0
+    local step = 1000 * 10
+    local total = timeout * 1000 * 1000
+    while step * count < total do
+        count = count + 1
+        C.usleep(step)
+        local ok, err = waitpid_nohang(pid)
+        if err then
+            return nil, err
+        end
+        if ok then
+            return true
+        end
+    end
+end
+
+
 return _M

apisix/init.lua

@@ -134,6 +134,11 @@ function _M.http_init_worker()
 end
 
 
+function _M.http_exit_worker()
+    require("apisix.plugins.ext-plugin.init").exit_worker()
+end
+
+
 function _M.http_ssl_phase()
     local ngx_ctx = ngx.ctx
     local api_ctx = ngx_ctx.api_ctx

apisix/plugins/ext-plugin/init.lua

@@ -36,6 +36,7 @@ if is_http then
     ngx_pipe = require("ngx.pipe")
     events = require("resty.worker.events")
 end
+local resty_signal = require "resty.signal"
 local bit = require("bit")
 local band = bit.band
 local lshift = bit.lshift
@@ -588,8 +589,10 @@ local function spawn_proc(cmd)
 end
 
 
+local runner
 local function setup_runner(cmd)
-    local proc = spawn_proc(cmd)
+    runner = spawn_proc(cmd)
+
     ngx_timer_at(0, function(premature)
         if premature then
             return
@@ -599,7 +602,7 @@ local function setup_runner(cmd)
             while true do
                 -- drain output
                 local max = 3800 -- smaller than Nginx error log length limit
-                local data, err = proc:stdout_read_any(max)
+                local data, err = runner:stdout_read_any(max)
                 if not data then
                     if exiting() then
                         return
@@ -615,11 +618,13 @@ local function setup_runner(cmd)
                 end
             end
 
-            local ok, reason, status = proc:wait()
+            local ok, reason, status = runner:wait()
             if not ok then
                 core.log.warn("runner exited with reason: ", reason, ", status: ", status)
             end
 
+            runner = nil
+
             local ok, err = events.post(events_list._source, events_list.runner_exit)
             if not ok then
                 core.log.error("post event failure with ", events_list._source, ", error: ", err)
@@ -628,7 +633,7 @@ local function setup_runner(cmd)
             core.log.warn("respawn runner 3 seconds later with cmd: ", core.json.encode(cmd))
             core.utils.sleep(3)
             core.log.warn("respawning new runner...")
-            proc = spawn_proc(cmd)
+            runner = spawn_proc(cmd)
         end
     end)
 end
@@ -656,4 +661,21 @@ function _M.init_worker()
 end
 
 
+function _M.exit_worker()
+    if process.type() == "privileged agent" and runner then
+        -- We need to send SIGTERM in the exit_worker phase, as:
+        -- 1. privileged agent doesn't support graceful exiting when I write this
+        -- 2. better to make it work without graceful exiting
+        local pid = runner:pid()
+        core.log.notice("terminate runner ", pid, " with SIGTERM")
+        local num = resty_signal.signum("TERM")
+        runner:kill(num)
+
+        -- give 1s to clean up the mess
+        core.os.waitpid(pid, 1)
+        -- then we KILL it via gc finalizer
+    end
+end
+
+
 return _M

docs/en/latest/external-plugin.md

@@ -103,3 +103,14 @@ nginx_config:
   envs:
     - MY_ENV_VAR
 ```
+
+### APISIX terminates my runner with SIGKILL but not SIGTERM!
+
+Since `v2.7`, APISIX will stop the runner with SIGTERM when it is running on
+OpenResty 1.19+.
+
+However, APISIX needs to wait the runner to quit so that we can ensure the resource
+for the process group is freed.
+
+Therefore, we send SIGTERM first. And then after 1 second, if the runner is still
+running, we will send SIGKILL.

t/APISIX.pm

@@ -398,7 +398,17 @@ _EOC_
         require("apisix").http_init_worker()
         $extra_init_worker_by_lua
     }
+_EOC_
 
+    if ($version !~ m/\/1.17.8/) {
+    $http_config .= <<_EOC_;
+    exit_worker_by_lua_block {
+        require("apisix").http_exit_worker()
+    }
+_EOC_
+    }
+
+    $http_config .= <<_EOC_;
     log_format main escape=default '\$remote_addr - \$remote_user [\$time_local] \$http_host "\$request" \$status \$body_bytes_sent \$request_time "\$http_referer" "\$http_user_agent" \$upstream_addr \$upstream_status \$upstream_response_time "\$upstream_scheme://\$upstream_host\$upstream_uri"';
 
     # fake server, only for test

t/plugin/ext-plugin/runner_can_not_terminated.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env 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.
+#
+
+term() {
+    eval sleep 1800
+}
+trap term SIGTERM
+sleep 1800

t/plugin/ext-plugin/sanity.t

@@ -445,3 +445,26 @@ MY_ENV_VAR foo
 {"error_msg":"failed to check the configuration of plugin ext-plugin-pre-req err: property \"conf\" validation failed: failed to validate item 1: property \"name\" is required"}
 
 {"error_msg":"failed to check the configuration of plugin ext-plugin-post-req err: property \"conf\" validation failed: failed to validate item 1: property \"value\" is required"}
+
+
+
+=== TEST 15: terminate spawn runner
+--- skip_nginx: 5: > 1.19.0
+--- ext_plugin_cmd
+["t/plugin/ext-plugin/runner.sh", "3600"]
+--- config
+    location /t {
+        return 200;
+    }
+--- shutdown_error_log eval
+qr/terminate runner \d+ with SIGTERM/
+
+
+
+=== TEST 16: spawn runner which can't be terminated, ensure APISIX won't be blocked
+--- ext_plugin_cmd
+["t/plugin/ext-plugin/runner_can_not_terminated.sh"]
+--- config
+    location /t {
+        return 200;
+    }