[runtime] add runtime configuration support (VKCOM#667)

Add the ability to specify a json-config as a server argument to be used inside the script with 'kphp_get_runtime_config()'.

builtin-functions/_functions.txt

@@ -173,6 +173,7 @@ function exit($code = 0) ::: void;
 function die($code = 0) ::: void;
 function register_kphp_on_warning_callback(callable(string $warning_message, string[] $stacktrace):void $stacktrace) ::: void;
 function kphp_set_context_on_error(mixed[] $tags, mixed $extra_info, string $env = "") ::: void;
+function kphp_get_runtime_config() ::: mixed;
 function kphp_backtrace($pretty ::: bool = true) ::: string[];
 
 function ini_get ($s ::: string) ::: string | false;

runtime/interface.cpp

@@ -85,6 +85,12 @@ bool is_json_log_on_timeout_enabled = true;
 
 static int ignore_level = 0;
 
+mixed runtime_config;
+
+mixed f$kphp_get_runtime_config() {
+  return runtime_config;
+}
+
 void f$ob_clean() {
   coub->clean();
 }

runtime/interface.h

@@ -121,6 +121,9 @@ bool f$get_magic_quotes_gpc();
 
 string f$php_sapi_name();
 
+extern mixed runtime_config;
+
+mixed f$kphp_get_runtime_config();
 
 extern mixed v$_SERVER;
 extern mixed v$_GET;

server/php-engine.cpp

@@ -8,6 +8,7 @@
 #include <cerrno>
 #include <cstdlib>
 #include <cstring>
+#include <fstream>
 #include <limits>
 #include <netdb.h>
 #include <netinet/in.h>
@@ -57,6 +58,7 @@
 #include "runtime/interface.h"
 #include "runtime/profiler.h"
 #include "runtime/rpc.h"
+#include "runtime/json-functions.h"
 #include "server/cluster-name.h"
 #include "server/confdata-binlog-replay.h"
 #include "server/database-drivers/adaptor.h"
@@ -2143,6 +2145,22 @@ int main_args_handler(int i, const char *long_option) {
       }
       return 0;
     }
+    case 2032: {
+      std::ifstream file(optarg);
+      if (!file) {
+        kprintf("--%s option : file opening failed\n", long_option);
+        return -1;
+      }
+      std::stringstream stringstream;
+      stringstream << file.rdbuf();
+      auto [config, success] = json_decode(string(stringstream.str().c_str()));
+      if (!success) {
+        kprintf("--%s option : file is not JSON\n", long_option);
+        return -1;
+      }
+      runtime_config = std::move(config);
+      return 0;
+    }
     default:
       return -1;
   }
@@ -2245,6 +2263,7 @@ void parse_main_args(int argc, char *argv[]) {
                                                                                              "memory limit = per_process_memory * processes_count");
   parse_option("job-workers-shared-messages-process-multiplier", required_argument, 2031, "Coefficient used to calculate the total count of the shared messages for job workers related communication:\n"
                                                                                           "messages count = coefficient * processes_count");
+  parse_option("runtime-config", required_argument, 2032, "JSON file path that will be available at runtime as 'mixed' via 'kphp_runtime_config()");
   parse_engine_options_long(argc, argv, main_args_handler);
   parse_main_args_till_option(argc, argv);
   // TODO: remove it after successful migration from kphb.readyV2 to kphb.readyV3

tests/python/tests/http_server/php/data/runtime_configuration.json

@@ -0,0 +1,4 @@
+{
+  "name": "simple configuration",
+  "version": "1.0.0"
+}

tests/python/tests/http_server/php/index.php

@@ -132,6 +132,22 @@ public function work() {
         echo "ERROR"; return;
     }
     echo "OK";
+} else if ($_SERVER["PHP_SELF"] === "/test_runtime_config") {
+    $config = kphp_get_runtime_config();
+    switch ($_GET["mode"]) {
+     case "read_only":
+         echo "name : " . $config["name"] . " ";
+         echo "version : " . $config["version"] . " ";
+         break;
+     case "modify":
+         $config["version"] = "1.0.1";
+         echo "modified version : " . $config["version"] . " ";
+         echo "old version : " . kphp_get_runtime_config()["version"] . " ";
+         break;
+     default:
+     echo "ERROR"; return;
+    }
+    echo "OK";
 } else if ($_SERVER["PHP_SELF"] === "/test_big_post_data") {
     $keys = array_keys($_POST);
     if ($keys) {

tests/python/tests/http_server/test_runtime_config.py

@@ -0,0 +1,22 @@
+from python.lib.testcase import KphpServerAutoTestCase
+
+class TestRuntimeConfig(KphpServerAutoTestCase):
+
+    @classmethod
+    def extra_class_setup(cls):
+        cls.kphp_server.update_options({
+            "--runtime-config": "./data/runtime_configuration.json"
+        })
+
+
+    def test_read_only(self):
+        response = self.kphp_server.http_request(uri="/test_runtime_config?mode=read_only")
+        self.assertEqual(200, response.status_code)
+        self.assertEqual(response.reason, "OK")
+        self.assertEqual(response.content, b'name : simple configuration version : 1.0.0 OK')
+
+    def test_modifying(self):
+        response = self.kphp_server.http_request(uri="/test_runtime_config?mode=modify")
+        self.assertEqual(200, response.status_code)
+        self.assertEqual(response.reason, "OK")
+        self.assertEqual(response.content, b'modified version : 1.0.1 old version : 1.0.0 OK')