Make server a daemon process. Support for start and stop subcommands.

Outline usage profile of the fiphoboserver executable in the README

Change log:
* start server daemon subcommand
* move appropriate flags to start subcommand
* main function forks process given start command
* stop command to kill running server process
* integration tests: reflect subcommand invoking of server
* detail usage in README

README.md

@@ -53,7 +53,7 @@ Option | Effect
 `-DCMAKE_CXX_COMPILER=...` | Set the C++ compiler.
 `-DCMAKE_CXX_FLAGS=...`    | Set the flags to pass to the C++ compiler. Overrides the default flags.
 
-#### Enabling / Disabling Sections of FIPhoboServer
+#### Enabling/Disabling Sections of FIPhoboServer
 Option | Effect
 ------ | ------
 `-DFIPHOBOSERVER_BUILD_TESTS=...`     | Set to `ON` to build FIPhoboServer tests and enable the `make test` target, or `OFF` to skip (Default `OFF`).
@@ -66,3 +66,28 @@ Integration tests can be run from the `test/integration_tests/` directory with `
 
 ## Documentation
 The Doxygen documentation can be found [here](doc/Markdown/fiphoboserver).
+
+## Usage
+
+The `fiphoboserver` executable requires exactly one subcommand.
+
+#### Subcommands
+Subcommand | Effect
+---------- | ------
+`start [hostname]` | Start the server daemon, listening to `hostname`.
+`stop`             | Stop the server daemon.
+
+The `start` subcommand supports a number of optional flags and options.
+
+#### Flags/Options
+Flag/Option | Effect
+----------- | ------
+`--http INT`             | Set the port to listen on with HTTP protocol.
+`--http2 INT`            | Set the port to listen on with HTTP2 protocol.
+`-t,--threads INT`       | Set the number of threads to listen on (<= 0 will use number of available cores).
+`-w,--write-config TEXT` | Write the configuration to `TEXT`
+
+Options can also be given to the `start` subcommand using `--config [config_filename]`. Note that if `hostname` is specified in the configuration file then the `--config` options must be suppied before the `start` subcommand;
+```
+fiphoboserver --config [config_filename] start
+```

src/main.cc

@@ -13,6 +13,10 @@
 #include <proxygen/httpserver/HTTPServer.h>
 #include <proxygen/httpserver/RequestHandlerFactory.h>
 
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+
 #include "fiphoboserver_exception.h"
 #include "server/handler_factory.h"
 #include "utils/config.h"
@@ -32,21 +36,74 @@ int main(int argc, char* argv[])
         parse_result = config.parse(argc, argv);
     }
     catch (const fiphoboserver::FIPhoboServerException& ex) {
-        return 0;
+        return EXIT_SUCCESS;
     }
-
     std::vector<proxygen::HTTPServer::IPConfig> IPs;  // NOLINT
-    try {
-        IPs = {
-            {SocketAddress(parse_result.ip, parse_result.http_port, true),
-             Protocol::HTTP},
-            {SocketAddress(parse_result.ip, parse_result.http2_port, true),
-             Protocol::HTTP2},
-        };
+
+    std::string pid_filename("/tmp/fiphoboserver_pid");
+    if (config.start_daemon()) {
+        try {
+            IPs = {
+                {SocketAddress(parse_result.ip, parse_result.http_port, true),
+                 Protocol::HTTP},
+                {SocketAddress(parse_result.ip, parse_result.http2_port, true),
+                 Protocol::HTTP2},
+            };
+        }
+        catch (const std::system_error& ex) {
+            std::cerr << "fiphoboserver: " << ex.what() << '\n';
+            return EXIT_FAILURE;
+        }
+
+        pid_t pid, sid;
+
+        pid = fork();
+        if (pid < 0) {
+            return EXIT_FAILURE;
+        }
+        if (pid > 0) {
+            return EXIT_SUCCESS;
+        }
+
+        umask(0);
+        chdir("/");
+
+        sid = setsid();
+        if (sid < 0) {
+            return EXIT_FAILURE;
+        }
+
+        std::ofstream pid_file(
+            pid_filename, std::ofstream::out | std::ofstream::trunc);
+        pid_file << sid;
+        pid_file.close();
+
+        /* close standard file descriptors */
+        close(STDIN_FILENO);
+        close(STDOUT_FILENO);
+        close(STDERR_FILENO);
     }
-    catch (const std::system_error& ex) {
-        std::cerr << "fiphoboserver: " << ex.what() << '\n';
-        return 1;
+    if (config.stop_daemon()) {
+        pid_t pid;
+
+        std::ifstream pid_file(pid_filename);
+        if (pid_file.good()) {
+            pid_file >> pid;
+            remove(pid_filename.c_str());
+        }
+        else {
+            std::cerr
+                << "fiphoboserver: Error stopping the server daemon. Is the server daemon running?"
+                << '\n';
+            return EXIT_FAILURE;
+        }
+
+        int rc = kill(pid, SIGTERM);
+        if (rc < 0) {
+            std::cerr
+                << "fiphoboserver: Error stopping the server daemon. terminate signal unsuccessful";
+        }
+        return EXIT_SUCCESS;
     }
 
     proxygen::HTTPServerOptions options;
@@ -72,5 +129,5 @@ int main(int argc, char* argv[])
     std::thread t([&]() { server.start(); });
 
     t.join();
-    return 0;
+    return EXIT_SUCCESS;
 }

src/utils/config.cc

@@ -15,6 +15,7 @@ cli_options Config::parse(int argc, char* argv[])
         m_parser.parse(argc, argv);
     }
     catch (const CLI::ParseError& e) {
+        std::cout << "m_hostname = " << m_hostname << std::endl;
         m_parser.exit(e);
         throw FIPhoboServerException(
             "Returning after command line parsing. --help or invalid argument(s)");
@@ -24,17 +25,23 @@ cli_options Config::parse(int argc, char* argv[])
 
 void Config::define_options()
 {
-    m_parser.add_option("hostname,--hostname", m_ip, "IP/Hostname to bind to")
+    m_parser.require_subcommand(1, 1);
+    m_start = m_parser.add_subcommand("start", "start the server daemon");
+    m_stop  = m_parser.add_subcommand("stop", "stop the server daemon");
+
+    m_start
+        ->add_option(
+            "hostname,--hostname", m_hostname, "IP/Hostname to bind to")
         ->required();
-    m_parser.add_option(
+    m_start->add_option(
         "--http", m_http_port, "port to listen on with HTTP protocol");
-    m_parser.add_option(
+    m_start->add_option(
         "--http2", m_http2_port, "port to listen on with HTTP2 protocol");
-    m_parser.add_option(
+    m_start->add_option(
         "-t,--threads", m_thread_count, "number of threads to listen on");
 
     m_parser.set_config("--config");
-    m_parser.add_option(
+    m_start->add_option(
         "-w,--write-config", m_config_filename,
         "write configuration options to file");
 }
@@ -51,7 +58,7 @@ cli_options Config::handle_arguments()
         file.close();
     }
 
-    return {m_http_port, m_http2_port, m_ip, m_thread_count};
+    return {m_http_port, m_http2_port, m_hostname, m_thread_count};
 }
 
 }  // namespace util

src/utils/config.h

@@ -48,33 +48,27 @@ class Config {
     /// @returns      struct of command line options or error code
     ///
     cli_options parse(int argc, char* argv[]);
-    ///
-    /// @brief get the HTTP port
-    ///
-    /// @returns the HTTP port
-    ///
-    const int http_port() const { return m_http_port; }
 
     ///
-    /// @brief get the HTTP2 port
+    /// @brief query if the server daemon should be started
     ///
-    /// @returns the HTTP2 port
+    /// @returns whether the start subcommand has been parsed
     ///
-    const int http2_port() const { return m_http2_port; }
+    bool start_daemon() const { return m_start->parsed(); }
 
     ///
-    /// @brief get the IP/Hostname
+    /// @brief query if the server daemon should be stopped
     ///
-    /// @returns the IP/Hostname
+    /// @returns whether the stop subcommand has been parsed
     ///
-    const std::string ip() const { return m_ip; }
+    bool stop_daemon() const { return m_stop->parsed(); }
 
     ///
-    /// @brief get the number of threads
+    /// @brief query if the server daemon should be restarted
     ///
-    /// @returns the number of threads
+    /// @returns whether the restart subcommand has been parsed
     ///
-    const int threads() const { return m_thread_count; }
+    bool restart_daemon() const { return m_restart->parsed(); }
 
   private:
     ///
@@ -94,6 +88,21 @@ class Config {
     ///
     CLI::App m_parser;
 
+    ///
+    /// @brief CLI11 class for start subcommand
+    ///
+    CLI::App* m_start;
+
+    ///
+    /// @brief CLI11 class for stop subcommand
+    ///
+    CLI::App* m_stop;
+
+    ///
+    /// @brief CLI11 class for restart subcommand
+    ///
+    CLI::App* m_restart;
+
     ///
     /// @brief port to listen on with HTTP protocol
     ///
@@ -108,7 +117,7 @@ class Config {
     ///
     /// @brief IP/Hostname to bind to
     ///
-    std::string m_ip;
+    std::string m_hostname;
 
     ///
     /// @brief Number of threads to listen on

test/integration_tests/client.py

 import unittest
 
 import subprocess
-import signal
 import os
 from multiprocessing import Process
 
@@ -15,9 +14,10 @@ class Server_test_case(unittest.TestCase):
     def setUpClass(cls):
         cls.bucket_name = "ichec.phobos.7a3d12c6-632b-4291-b87e-07badca60cd0"
         cls.client = s3_client.S3_client('http://localhost:11000/')
-        cls.server = subprocess.Popen('../../build/fiphoboserver localhost',
-                                      shell=True,
-                                      preexec_fn=os.setsid)
+
+        # start the server daemon
+        subprocess.run("../../build/fiphoboserver start localhost", shell=True)
+
         cls.put_file_name = 'data/EmperorWu.txt'
         cls.get_file_name = 'data/EmperorWu_get.txt'
         cls.put_empty_file_name = 'data/empty.txt'
@@ -28,10 +28,9 @@ class Server_test_case(unittest.TestCase):
     def tearDownClass(cls):
         os.remove(cls.get_file_name)
         os.remove(cls.get_empty_file_name)
-        cls.server.terminate()
 
-        # kill the fiphoboserver process
-        os.killpg(os.getpgid(cls.server.pid), signal.SIGTERM)
+        # start the server daemon
+        subprocess.run("../../build/fiphoboserver stop", shell=True)
 
     def test_file_put_and_get(self):
         self.client.put(self.put_file_name, self.bucket_name, self.key)