add command module to handle request-response communications

10 files changed, 395 insertions, 224 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6f2cc6b..545fd82 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -36,6 +36,7 @@ generate_sql_header(sqlite)
 add_my_executable(server server_main.c server.c
     ci_queue.c
     cmd_line.c
+    command.c
     file.c
     msg.c
     net.c
@@ -57,6 +58,7 @@ add_my_executable(client client_main.c client.c
 add_my_executable(worker worker_main.c worker.c
     ci.c
     cmd_line.c
+    command.c
     file.c
     git.c
     msg.c
diff --git a/src/client.c b/src/client.c
index 739c612..14eab14 100644
--- a/src/client.c
+++ b/src/client.c
@@ -47,24 +47,31 @@ void client_destroy(struct client *client)
 	free(client);
 }
 
-int client_main(const struct client *client, int argc, char *argv[])
+int client_main(const struct client *client, const char **argv)
 {
-	struct msg request = {argc, argv};
-	struct msg response;
+	struct msg *request;
+	struct msg *response;
 	int ret = 0;
 
-	ret = msg_send_and_wait(client->fd, &request, &response);
+	ret = msg_from_argv(&request, argv);
 	if (ret < 0)
 		return ret;
 
-	if (msg_is_error(&response)) {
+	ret = msg_send_and_wait(client->fd, request, &response);
+	if (ret < 0)
+		goto free_request;
+
+	if (msg_is_error(response)) {
 		log_err("Server failed to process the request\n");
 		ret = -1;
 		goto free_response;
 	}
 
 free_response:
-	msg_free(&response);
+	msg_free(response);
+
+free_request:
+	msg_free(request);
 
 	return ret;
 }
diff --git a/src/client.h b/src/client.h
index 141c6be..5bc3f5c 100644
--- a/src/client.h
+++ b/src/client.h
@@ -18,6 +18,6 @@ struct client;
 int client_create(struct client **, const struct settings *);
 void client_destroy(struct client *);
 
-int client_main(const struct client *, int argc, char *argv[]);
+int client_main(const struct client *, const char **argv);
 
 #endif
diff --git a/src/client_main.c b/src/client_main.c
index a895ccf..dd22508 100644
--- a/src/client_main.c
+++ b/src/client_main.c
@@ -73,7 +73,7 @@ int main(int argc, char *argv[])
 	if (ret < 0)
 		return ret;
 
-	ret = client_main(client, argc - optind, argv + optind);
+	ret = client_main(client, (const char **)argv + optind);
 	if (ret < 0)
 		goto destroy_client;
 
diff --git a/src/command.c b/src/command.c
new file mode 100644
index 0000000..b1204a9
--- /dev/null
+++ b/src/command.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2023 Egor Tensin <Egor.Tensin@gmail.com>
+ * This file is part of the "cimple" project.
+ * For details, see https://github.com/egor-tensin/cimple.
+ * Distributed under the MIT License.
+ */
+
+#include "command.h"
+#include "log.h"
+#include "msg.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+struct command_dispatcher {
+	struct command_def *defs;
+	size_t numof_defs;
+	void *ctx;
+};
+
+static int copy_def(struct command_def *dest, const struct command_def *src)
+{
+	dest->name = strdup(src->name);
+	if (!dest->name) {
+		log_errno("strdup");
+		return -1;
+	}
+	dest->processor = src->processor;
+	return 0;
+}
+
+static void free_def(struct command_def *def)
+{
+	free(def->name);
+}
+
+static int copy_defs(struct command_def *dest, const struct command_def *src, size_t numof_defs)
+{
+	size_t numof_copied, i;
+	int ret = 0;
+
+	for (numof_copied = 0; numof_copied < numof_defs; ++numof_copied) {
+		ret = copy_def(&dest[numof_copied], &src[numof_copied]);
+		if (ret < 0)
+			goto free;
+	}
+
+	return 0;
+
+free:
+	for (i = 0; i < numof_copied; ++i)
+		free_def(&dest[numof_copied]);
+
+	return -1;
+}
+
+static void free_defs(struct command_def *defs, size_t numof_defs)
+{
+	size_t i;
+
+	for (i = 0; i < numof_defs; ++i)
+		free_def(&defs[i]);
+}
+
+int command_dispatcher_create(struct command_dispatcher **_dispatcher, struct command_def *defs,
+                              size_t numof_defs, void *ctx)
+{
+	struct command_dispatcher *dispatcher;
+	int ret = 0;
+
+	*_dispatcher = malloc(sizeof(struct command_dispatcher));
+	if (!*_dispatcher) {
+		log_errno("malloc");
+		return -1;
+	}
+	dispatcher = *_dispatcher;
+
+	dispatcher->defs = malloc(sizeof(struct command_def) * numof_defs);
+	if (!dispatcher->defs) {
+		log_errno("malloc");
+		goto free;
+	}
+	dispatcher->numof_defs = numof_defs;
+
+	ret = copy_defs(dispatcher->defs, defs, numof_defs);
+	if (ret < 0)
+		goto free_defs;
+
+	dispatcher->ctx = ctx;
+	return 0;
+
+free_defs:
+	free(dispatcher->defs);
+
+free:
+	free(dispatcher);
+
+	return -1;
+}
+
+void command_dispatcher_destroy(struct command_dispatcher *dispatcher)
+{
+	free_defs(dispatcher->defs, dispatcher->numof_defs);
+	free(dispatcher->defs);
+	free(dispatcher);
+}
+
+int command_dispatcher_msg_handler(const struct command_dispatcher *dispatcher, int conn_fd,
+                                   const struct msg *request)
+{
+	struct msg *response = NULL;
+	int ret = 0;
+
+	size_t numof_words = msg_get_length(request);
+	if (numof_words == 0)
+		goto unknown;
+
+	const char **words = msg_get_words(request);
+
+	for (size_t i = 0; i < dispatcher->numof_defs; ++i) {
+		struct command_def *def = &dispatcher->defs[i];
+
+		if (strcmp(def->name, words[0]))
+			continue;
+
+		ret = def->processor(conn_fd, request, dispatcher->ctx, &response);
+		goto exit;
+	}
+
+unknown:
+	log_err("Received an unknown command\n");
+	ret = -1;
+	msg_dump(request);
+	goto exit;
+
+exit:
+	if (ret < 0 && !response)
+		msg_error(&response);
+	if (response)
+		return msg_send(conn_fd, response);
+	return ret;
+}
+
+int command_dispatcher_conn_handler(int conn_fd, void *_dispatcher)
+{
+	struct command_dispatcher *dispatcher = (struct command_dispatcher *)_dispatcher;
+	struct msg *request;
+	int ret = 0;
+
+	ret = msg_recv(conn_fd, &request);
+	if (ret < 0)
+		return ret;
+
+	ret = command_dispatcher_msg_handler(dispatcher, conn_fd, request);
+	msg_free(request);
+	return ret;
+}
diff --git a/src/command.h b/src/command.h
new file mode 100644
index 0000000..b4c3b40
--- /dev/null
+++ b/src/command.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2023 Egor Tensin <Egor.Tensin@gmail.com>
+ * This file is part of the "cimple" project.
+ * For details, see https://github.com/egor-tensin/cimple.
+ * Distributed under the MIT License.
+ */
+
+#ifndef __COMMAND_H__
+#define __COMMAND_H__
+
+#include "msg.h"
+
+#include <stdlib.h>
+
+typedef int (*command_processor)(int conn_fd, const struct msg *request, void *ctx,
+                                 struct msg **response);
+
+struct command_def {
+	char *name;
+	command_processor processor;
+};
+
+struct command_dispatcher;
+
+int command_dispatcher_create(struct command_dispatcher **, struct command_def *, size_t numof_defs,
+                              void *ctx);
+void command_dispatcher_destroy(struct command_dispatcher *);
+
+int command_dispatcher_msg_handler(const struct command_dispatcher *, int conn_fd,
+                                   const struct msg *);
+
+/* This is supposed to be used as an argument to tcp_server_accept. */
+int command_dispatcher_conn_handler(int conn_fd, void *dispatcher);
+
+#endif
diff --git a/src/msg.c b/src/msg.c
index 0c8dfc7..18e4c25 100644
--- a/src/msg.c
+++ b/src/msg.c
@@ -13,13 +13,28 @@
 #include <stdlib.h>
 #include <string.h>
 
-int msg_success(struct msg *msg)
+struct msg {
+	size_t argc;
+	const char **argv;
+};
+
+size_t msg_get_length(const struct msg *msg)
+{
+	return msg->argc;
+}
+
+const char **msg_get_words(const struct msg *msg)
+{
+	return msg->argv;
+}
+
+int msg_success(struct msg **msg)
 {
 	const char *argv[] = {"success", NULL};
 	return msg_from_argv(msg, argv);
 }
 
-int msg_error(struct msg *msg)
+int msg_error(struct msg **msg)
 {
 	const char *argv[] = {"error", NULL};
 	return msg_from_argv(msg, argv);
@@ -37,82 +52,107 @@ int msg_is_error(const struct msg *msg)
 
 static int msg_copy_argv(struct msg *msg, const char **argv)
 {
-	msg->argv = calloc(msg->argc, sizeof(const char *));
+	size_t copied = 0;
 
+	msg->argv = calloc(msg->argc + 1, sizeof(const char *));
 	if (!msg->argv) {
 		log_errno("calloc");
 		return -1;
 	}
 
-	for (int i = 0; i < msg->argc; ++i) {
-		msg->argv[i] = strdup(argv[i]);
-		if (!msg->argv[i]) {
+	for (copied = 0; copied < msg->argc; ++copied) {
+		msg->argv[copied] = strdup(argv[copied]);
+		if (!msg->argv[copied]) {
 			log_errno("strdup");
-			goto free;
+			goto free_copied;
 		}
 	}
 
 	return 0;
 
-free:
-	msg_free(msg);
+free_copied:
+	for (size_t i = 0; i < copied; ++i) {
+		free((char *)msg->argv[i]);
+	}
+
+	free(msg->argv);
 
 	return -1;
 }
 
-struct msg *msg_copy(const struct msg *src)
+int msg_copy(struct msg **_dest, const struct msg *src)
 {
-	struct msg *dest;
+	struct msg *dest = NULL;
 	int ret = 0;
 
-	dest = malloc(sizeof(*dest));
-	if (!dest) {
-		log_errno("calloc");
-		return NULL;
+	*_dest = malloc(sizeof(struct msg));
+	if (!_dest) {
+		log_errno("malloc");
+		return -1;
 	}
+	dest = *_dest;
+
 	dest->argc = src->argc;
 
 	ret = msg_copy_argv(dest, (const char **)src->argv);
 	if (ret < 0)
 		goto free;
 
-	return dest;
+	return 0;
 
 free:
 	free(dest);
 
-	return NULL;
+	return -1;
 }
 
-void msg_free(const struct msg *msg)
+void msg_free(struct msg *msg)
 {
-	for (int i = 0; i < msg->argc; ++i)
+	for (size_t i = 0; i < msg->argc; ++i)
 		free((char *)msg->argv[i]);
 	free(msg->argv);
+	free(msg);
 }
 
-int msg_from_argv(struct msg *msg, const char **argv)
+int msg_from_argv(struct msg **_msg, const char **argv)
 {
-	int argc = 0;
+	struct msg *msg = NULL;
+	int ret = 0;
+
+	*_msg = malloc(sizeof(struct msg));
+	if (!*_msg) {
+		log_errno("malloc");
+		return -1;
+	}
+	msg = *_msg;
 
+	msg->argc = 0;
 	for (const char **s = argv; *s; ++s)
-		++argc;
+		++msg->argc;
+
+	ret = msg_copy_argv(msg, argv);
+	if (ret < 0)
+		goto free;
+
+	return 0;
+
+free:
+	free(msg);
 
-	msg->argc = argc;
-	return msg_copy_argv(msg, argv);
+	return -1;
 }
 
 static uint32_t calc_buf_size(const struct msg *msg)
 {
 	uint32_t len = 0;
-	for (int i = 0; i < msg->argc; ++i)
+	for (size_t i = 0; i < msg->argc; ++i)
 		len += strlen(msg->argv[i]) + 1;
 	return len;
 }
 
-static int calc_argv_len(const void *buf, size_t len)
+static size_t calc_argv_len(const void *buf, size_t len)
 {
-	int argc = 0;
+	size_t argc = 0;
 	for (const char *it = buf; it < (const char *)buf + len; it += strlen(it) + 1)
 		++argc;
 	return argc;
@@ -120,7 +160,7 @@ static int calc_argv_len(const void *buf, size_t len)
 
 static void argv_pack(char *dest, const struct msg *msg)
 {
-	for (int i = 0; i < msg->argc; ++i) {
+	for (size_t i = 0; i < msg->argc; ++i) {
 		strcpy(dest, msg->argv[i]);
 		dest += strlen(msg->argv[i]) + 1;
 	}
@@ -128,28 +168,31 @@ static void argv_pack(char *dest, const struct msg *msg)
 
 static int argv_unpack(struct msg *msg, const char *src)
 {
-	msg->argv = calloc(msg->argc, sizeof(char *));
+	size_t copied = 0;
+
+	msg->argv = calloc(msg->argc + 1, sizeof(const char *));
 	if (!msg->argv) {
 		log_errno("calloc");
 		return -1;
 	}
 
-	for (int i = 0; i < msg->argc; ++i) {
-		size_t len = strlen(src);
-
-		msg->argv[i] = malloc(len + 1);
-		if (!msg->argv[i]) {
-			log_errno("malloc");
+	for (copied = 0; copied < msg->argc; ++copied) {
+		msg->argv[copied] = strdup(src);
+		if (!msg->argv[copied]) {
+			log_errno("strdup");
 			goto free;
 		}
 
-		strcpy(msg->argv[i], src);
-		src += len + 1;
+		src += strlen(msg->argv[copied]) + 1;
 	}
 
 	return 0;
 
 free:
+	for (size_t i = 0; i < copied; ++i) {
+		free((char *)msg->argv[i]);
+	}
+
 	msg_free(msg);
 
 	return -1;
@@ -185,7 +228,7 @@ free_data:
 	return ret;
 }
 
-int msg_send_and_wait(int fd, const struct msg *request, struct msg *response)
+int msg_send_and_wait(int fd, const struct msg *request, struct msg **response)
 {
 	int ret = 0;
 
@@ -200,20 +243,34 @@ int msg_send_and_wait(int fd, const struct msg *request, struct msg *response)
 	return ret;
 }
 
-int msg_recv(int fd, struct msg *msg)
+int msg_recv(int fd, struct msg **_msg)
 {
-	struct buf *buf;
+	struct msg *msg = NULL;
+	struct buf *buf = NULL;
 	int ret = 0;
 
 	ret = net_recv_buf(fd, &buf);
 	if (ret < 0)
 		return ret;
 
+	*_msg = malloc(sizeof(struct msg));
+	if (!*_msg) {
+		log_errno("malloc");
+		ret = -1;
+		goto destroy_buf;
+	}
+	msg = *_msg;
+
 	msg->argc = calc_argv_len(buf_get_data(buf), buf_get_size(buf));
 
 	ret = argv_unpack(msg, buf_get_data(buf));
 	if (ret < 0)
-		goto destroy_buf;
+		goto free_msg;
+
+	goto destroy_buf;
+
+free_msg:
+	free(msg);
 
 destroy_buf:
 	buf_destroy(buf);
@@ -223,7 +280,7 @@ destroy_buf:
 
 void msg_dump(const struct msg *msg)
 {
-	log("Message[%d]:\n", msg->argc);
-	for (int i = 0; i < msg->argc; ++i)
+	log("Message[%zu]:\n", msg->argc);
+	for (size_t i = 0; i < msg->argc; ++i)
 		log("\t%s\n", msg->argv[i]);
 }
diff --git a/src/msg.h b/src/msg.h
index 2260016..2f631fc 100644
--- a/src/msg.h
+++ b/src/msg.h
@@ -8,26 +8,28 @@
 #ifndef __MSG_H__
 #define __MSG_H__
 
-struct msg {
-	int argc;
-	char **argv;
-};
+#include <stdlib.h>
 
-int msg_success(struct msg *);
-int msg_error(struct msg *);
+struct msg;
+
+size_t msg_get_length(const struct msg *);
+const char **msg_get_words(const struct msg *);
+
+int msg_success(struct msg **);
+int msg_error(struct msg **);
 
 int msg_is_success(const struct msg *);
 int msg_is_error(const struct msg *);
 
-struct msg *msg_copy(const struct msg *);
-void msg_free(const struct msg *);
+int msg_copy(struct msg **, const struct msg *);
+void msg_free(struct msg *);
 
-int msg_from_argv(struct msg *, const char **argv);
+int msg_from_argv(struct msg **, const char **argv);
 
-int msg_recv(int fd, struct msg *);
+int msg_recv(int fd, struct msg **);
 int msg_send(int fd, const struct msg *);
 
-int msg_send_and_wait(int fd, const struct msg *, struct msg *response);
+int msg_send_and_wait(int fd, const struct msg *, struct msg **response);
 
 void msg_dump(const struct msg *);
 
diff --git a/src/server.c b/src/server.c
index 22a9a86..806da11 100644
--- a/src/server.c
+++ b/src/server.c
@@ -7,6 +7,7 @@
 
 #include "server.h"
 #include "ci_queue.h"
+#include "command.h"
 #include "compiler.h"
 #include "const.h"
 #include "log.h"
@@ -18,7 +19,6 @@
 
 #include <pthread.h>
 #include <stdlib.h>
-#include <string.h>
 
 struct server {
 	pthread_mutex_t server_mtx;
@@ -111,7 +111,7 @@ static int server_has_runs(const struct server *server)
 
 static int worker_ci_run(int fd, const struct ci_queue_entry *ci_run)
 {
-	struct msg request, response;
+	struct msg *request, *response;
 	int ret = 0;
 
 	const char *argv[] = {CMD_CI_RUN, ci_queue_entry_get_url(ci_run),
@@ -121,21 +121,21 @@ static int worker_ci_run(int fd, const struct ci_queue_entry *ci_run)
 	if (ret < 0)
 		return ret;
 
-	ret = msg_send_and_wait(fd, &request, &response);
-	msg_free(&request);
+	ret = msg_send_and_wait(fd, request, &response);
+	msg_free(request);
 	if (ret < 0)
 		return ret;
 
-	if (response.argc < 0) {
+	if (!msg_is_success(response)) {
 		log_err("Failed to schedule a CI run: worker is busy?\n");
-		ret = -1;
+		msg_dump(response);
 		goto free_response;
 	}
 
 	/* TODO: handle the response. */
 
 free_response:
-	msg_free(&response);
+	msg_free(response);
 
 	return ret;
 }
@@ -234,15 +234,10 @@ static int worker_thread(struct server *server, int fd)
 	return ret;
 }
 
-static int msg_new_worker_handler(struct server *server, int client_fd,
-                                  UNUSED const struct msg *request)
+static int msg_new_worker_handler(int client_fd, UNUSED const struct msg *request, void *_server,
+                                  UNUSED struct msg **response)
 {
-	return worker_thread(server, client_fd);
-}
-
-static int msg_new_worker_parser(UNUSED const struct msg *msg)
-{
-	return 1;
+	return worker_thread((struct server *)_server, client_fd);
 }
 
 static int msg_ci_run_queue(struct server *server, const char *url, const char *rev)
@@ -276,87 +271,33 @@ unlock:
 	return ret;
 }
 
-static int msg_ci_run_handler(struct server *server, int client_fd, const struct msg *msg)
+static int msg_ci_run_handler(UNUSED int client_fd, const struct msg *request, void *_server,
+                              struct msg **response)
 {
-	struct msg response;
+	struct server *server = (struct server *)_server;
 	int ret = 0;
 
-	ret = msg_ci_run_queue(server, msg->argv[1], msg->argv[2]);
-	if (ret < 0)
-		ret = msg_error(&response);
-	else
-		ret = msg_success(&response);
-
-	if (ret < 0)
-		return ret;
-
-	ret = msg_send(client_fd, &response);
-	msg_free(&response);
-	return ret;
-}
-
-static int msg_ci_run_parser(const struct msg *msg)
-{
-	if (msg->argc != 3) {
-		log_err("Invalid number of arguments for a message: %d\n", msg->argc);
-		return 0;
-	}
-
-	return 1;
-}
-
-typedef int (*msg_parser)(const struct msg *msg);
-typedef int (*msg_handler)(struct server *, int client_fd, const struct msg *msg);
-
-struct msg_descr {
-	const char *cmd;
-	msg_parser parser;
-	msg_handler handler;
-};
-
-struct msg_descr messages[] = {
-    {CMD_NEW_WORKER, msg_new_worker_parser, msg_new_worker_handler},
-    {CMD_CI_RUN, msg_ci_run_parser, msg_ci_run_handler},
-};
-
-static int server_msg_handler(struct server *server, int client_fd, const struct msg *request)
-{
-	if (request->argc == 0)
-		goto unknown_request;
-
-	size_t numof_messages = sizeof(messages) / sizeof(messages[0]);
-
-	for (size_t i = 0; i < numof_messages; ++i) {
-		if (strcmp(messages[i].cmd, request->argv[0]))
-			continue;
-		if (!messages[i].parser(request))
-			continue;
-		return messages[i].handler(server, client_fd, request);
+	if (msg_get_length(request) != 3) {
+		log_err("Invalid number of arguments for a message: %zu\n",
+		        msg_get_length(request));
+		msg_dump(request);
+		return -1;
 	}
 
-unknown_request:
-	log_err("Received an unknown message\n");
-	msg_dump(request);
-	struct msg response;
-	msg_error(&response);
-	return msg_send(client_fd, &response);
-}
-
-static int server_conn_handler(int client_fd, void *_server)
-{
-	struct server *server = (struct server *)_server;
-	struct msg request;
-	int ret = 0;
+	const char **words = msg_get_words(request);
 
-	ret = msg_recv(client_fd, &request);
+	ret = msg_ci_run_queue(server, words[1], words[2]);
 	if (ret < 0)
 		return ret;
 
-	ret = server_msg_handler(server, client_fd, &request);
-	msg_free(&request);
-	return ret;
+	return msg_success(response);
 }
 
+static struct command_def commands[] = {
+    {CMD_NEW_WORKER, msg_new_worker_handler},
+    {CMD_CI_RUN, msg_ci_run_handler},
+};
+
 static int server_set_stopping(struct server *server)
 {
 	int ret = 0;
@@ -383,24 +324,32 @@ unlock:
 
 int server_main(struct server *server)
 {
+	struct command_dispatcher *dispatcher = NULL;
 	int ret = 0;
 
 	ret = signal_install_global_handler();
 	if (ret < 0)
 		return ret;
 
+	ret = command_dispatcher_create(&dispatcher, commands,
+	                                sizeof(commands) / sizeof(commands[0]), server);
+	if (ret < 0)
+		return ret;
+
 	while (!global_stop_flag) {
 		log("Waiting for new connections\n");
 
-		ret = tcp_server_accept(server->tcp_server, server_conn_handler, server);
+		ret = tcp_server_accept(server->tcp_server, command_dispatcher_conn_handler,
+		                        dispatcher);
 		if (ret < 0) {
-			if (errno == EINVAL && global_stop_flag) {
+			if (errno == EINVAL && global_stop_flag)
 				ret = 0;
-				break;
-			}
-			return ret;
+			goto dispatcher_destroy;
 		}
 	}
 
+dispatcher_destroy:
+	command_dispatcher_destroy(dispatcher);
+
 	return server_set_stopping(server);
 }
diff --git a/src/worker.c b/src/worker.c
index ed3d7e5..ae9a578 100644
--- a/src/worker.c
+++ b/src/worker.c
@@ -7,6 +7,7 @@
 
 #include "worker.h"
 #include "ci.h"
+#include "command.h"
 #include "compiler.h"
 #include "const.h"
 #include "git.h"
@@ -16,8 +17,8 @@
 #include "process.h"
 #include "signal.h"
 
+#include <pthread.h>
 #include <stdlib.h>
-#include <string.h>
 #include <unistd.h>
 
 struct worker {
@@ -73,20 +74,15 @@ void worker_destroy(struct worker *worker)
 static int msg_send_new_worker(const struct worker *worker)
 {
 	static const char *argv[] = {CMD_NEW_WORKER, NULL};
-	struct msg msg;
+	struct msg *msg;
 	int ret = 0;
 
 	ret = msg_from_argv(&msg, argv);
 	if (ret < 0)
 		return ret;
 
-	ret = msg_send(worker->fd, &msg);
-	if (ret < 0)
-		goto free_msg;
-
-free_msg:
-	msg_free(&msg);
-
+	ret = msg_send(worker->fd, msg);
+	msg_free(msg);
 	return ret;
 }
 
@@ -109,77 +105,37 @@ static int msg_ci_run_do(const char *url, const char *rev, struct proc_output *r
 	return 0;
 }
 
-static int msg_ci_run_handler(struct worker *worker, const struct msg *request)
+static int msg_ci_run_handler(UNUSED int conn_fd, const struct msg *request, UNUSED void *_worker,
+                              struct msg **response)
 {
-	struct msg response;
 	struct proc_output result;
 	int ret = 0;
 
+	if (msg_get_length(request) != 3) {
+		log_err("Invalid number of arguments for a message\n");
+		msg_dump(request);
+		return -1;
+	}
+
+	const char **words = msg_get_words(request);
+
 	proc_output_init(&result);
-	ret = msg_ci_run_do(request->argv[1], request->argv[2], &result);
+	ret = msg_ci_run_do(words[1], words[2], &result);
 	proc_output_free(&result);
 
 	if (ret < 0)
-		ret = msg_error(&response);
-	else
-		ret = msg_success(&response);
-
-	if (ret < 0)
 		return ret;
 
-	ret = msg_send(worker->fd, &response);
-	msg_free(&response);
-	return ret;
-}
-
-static int msg_ci_run_parser(const struct msg *msg)
-{
-	if (msg->argc != 3) {
-		log_err("Invalid number of arguments for a message: %d\n", msg->argc);
-		return 0;
-	}
-
-	return 1;
+	return msg_success(response);
 }
 
-typedef int (*msg_parser)(const struct msg *msg);
-typedef int (*msg_handler)(struct worker *, const struct msg *);
-
-struct msg_descr {
-	const char *cmd;
-	msg_parser parser;
-	msg_handler handler;
-};
-
-struct msg_descr messages[] = {
-    {CMD_CI_RUN, msg_ci_run_parser, msg_ci_run_handler},
+static struct command_def commands[] = {
+    {CMD_CI_RUN, msg_ci_run_handler},
 };
 
-static int worker_msg_handler(struct worker *worker, const struct msg *request)
-{
-	if (request->argc == 0)
-		goto unknown_request;
-
-	size_t numof_messages = sizeof(messages) / sizeof(messages[0]);
-
-	for (size_t i = 0; i < numof_messages; ++i) {
-		if (strcmp(messages[i].cmd, request->argv[0]))
-			continue;
-		if (!messages[i].parser(request))
-			continue;
-		return messages[i].handler(worker, request);
-	}
-
-unknown_request:
-	log_err("Received an unknown message\n");
-	msg_dump(request);
-	struct msg response;
-	msg_error(&response);
-	return msg_send(worker->fd, &response);
-}
-
 int worker_main(struct worker *worker, UNUSED int argc, UNUSED char *argv[])
 {
+	struct command_dispatcher *dispatcher = NULL;
 	int ret = 0;
 
 	ret = signal_install_global_handler();
@@ -190,25 +146,31 @@ int worker_main(struct worker *worker, UNUSED int argc, UNUSED char *argv[])
 	if (ret < 0)
 		return ret;
 
+	ret = command_dispatcher_create(&dispatcher, commands,
+	                                sizeof(commands) / sizeof(commands[0]), worker);
+	if (ret < 0)
+		return ret;
+
 	while (!global_stop_flag) {
-		struct msg request;
+		struct msg *request;
 
 		log("Waiting for a new command\n");
 
 		ret = msg_recv(worker->fd, &request);
 		if (ret < 0) {
-			if (errno == EINVAL && global_stop_flag) {
+			if (errno == EINVAL && global_stop_flag)
 				ret = 0;
-				break;
-			}
-			return ret;
+			goto dispatcher_destroy;
 		}
 
-		ret = worker_msg_handler(worker, &request);
-		msg_free(&request);
+		ret = command_dispatcher_msg_handler(dispatcher, worker->fd, request);
+		msg_free(request);
 		if (ret < 0)
-			return ret;
+			goto dispatcher_destroy;
 	}
 
+dispatcher_destroy:
+	command_dispatcher_destroy(dispatcher);
+
 	return ret;
 }