Skynet源码之：日志打印(13)

FILE * 
skynet_log_open(struct skynet_context * ctx, uint32_t handle) {
	const char * logpath = skynet_getenv("logpath"); // 这里就会使用 配置字段 logpath = "." 
	if (logpath == NULL)
		return NULL;
	size_t sz = strlen(logpath);
	char tmp[sz + 16];
	sprintf(tmp, "%s/%08x.log", logpath, handle);
	FILE *f = fopen(tmp, "ab"); // 打开一个日志文件
	if (f) {
		uint32_t starttime = skynet_starttime();
		uint64_t currenttime = skynet_now();
		time_t ti = starttime + currenttime/100;
		skynet_error(ctx, "Open log file %s", tmp); // 给 service_logger 服务发个消息，内容是 open log 
		fprintf(f, "open time: %u %s", (uint32_t)currenttime, ctime(&ti));
		fflush(f); // 正式把刚才的 open time 这条日志输入到新文件
	} else {
		skynet_error(ctx, "Open log file %s fail", tmp);
	}
	return f;
}

skynet.error = c.error -- 即调用c层的error函数

static int
lerror(lua_State *L) {
	struct skynet_context * context = lua_touserdata(L, lua_upvalueindex(1));
	int n = lua_gettop(L);
	if (n <= 1) {
		lua_settop(L, 1);
		const char * s = luaL_tolstring(L, 1, NULL);
		skynet_error(context, "%s", s);
		return 0;
	}
	luaL_Buffer b;
	luaL_buffinit(L, &b);
	int i;
	for (i=1; i<=n; i++) {
		luaL_tolstring(L, i, NULL);
		luaL_addvalue(&b);
		if (i<n) {
			luaL_addchar(&b, ' ');
		}
	}
	luaL_pushresult(&b);
    
    // 最终调用c层的skynet_error()函数
    // 在skynet_error.c文件中定义
	skynet_error(context, "%s", lua_tostring(L, -1)); 
	return 0;
}

void 
skynet_error(struct skynet_context * context, const char *msg, ...) {
	static uint32_t logger = 0;
	if (logger == 0) {
		logger = skynet_handle_findname("logger");
	}
	if (logger == 0) {
		return;
	}
    
    // 代码省略
    
    struct skynet_message smsg;
    if (context == NULL) {
        smsg.source = 0;
    } else {
        smsg.source = skynet_context_handle(context);
    }
    smsg.session = 0;
    smsg.data = data;
    smsg.sz = len | ((size_t)PTYPE_TEXT << MESSAGE_TYPE_SHIFT);
    skynet_context_push(logger, &smsg); // skynet.error()最终的本质就是给service_logger发个消息
}

// service_logger.c文件
static int
logger_cb(struct skynet_context * context, void *ud, int type, int session, uint32_t source, const void * msg, size_t sz) {
	struct logger * inst = ud;
	switch (type) {
	case PTYPE_SYSTEM:
		if (inst->filename) {
			inst->handle = freopen(inst->filename, "a", inst->handle);
		}
		break;
	case PTYPE_TEXT:
        // ******************************************************日志输出在此打印
		if (inst->filename) {
			char tmp[SIZETIMEFMT];
			int csec = timestring(ud, tmp);
			fprintf(inst->handle, "%s.%02d ", tmp, csec);
		}
		fprintf(inst->handle, "[:%08x] ", source);
		fwrite(msg, sz , 1, inst->handle);
		fprintf(inst->handle, "\n");
		fflush(inst->handle);
		break;
        // ******************************************************日志输出在此打印
	}

	return 0;
}

// 在skynet_server.c文件中
static void
dispatch_message(struct skynet_context *ctx, struct skynet_message *msg) {
	
    // 代码省略
    
    // 其中ctx->logfile是在服务创建时候初始化的
    // 详细请看《Skynet源码之：服务实现》
	FILE *f = (FILE *)ATOM_LOAD(&ctx->logfile); // 假如服务有标记logfile字段
	if (f) {
		skynet_log_output(f, msg->source, type, msg->session, msg->data, sz);
	}
}
// 对于ATOM_LOAD()的作用，请看《Skynet专题之：原子操作》

// skynet_server.c文件
static const char *
cmd_logon(struct skynet_context * context, const char * param) {
	printf("%s\n", param);
	uint32_t handle = tohandle(context, param);
	if (handle == 0)
		return NULL;
	struct skynet_context * ctx = skynet_handle_grab(handle);
	if (ctx == NULL)
		return NULL;
	FILE *f = NULL;
	FILE * lastf = (FILE *)ATOM_LOAD(&ctx->logfile);// 注意这行代码
	if (lastf == NULL) {
		f = skynet_log_open(context, handle);
		if (f) {
			if (!ATOM_CAS_POINTER(&ctx->logfile, 0, (uintptr_t)f)) {
				// logfile opens in other thread, close this one.
				fclose(f);
			}
		}
	}
	skynet_context_release(ctx);
	return NULL;
}

static const char *
cmd_logoff(struct skynet_context * context, const char * param) {
	uint32_t handle = tohandle(context, param);
	if (handle == 0)
		return NULL;
	struct skynet_context * ctx = skynet_handle_grab(handle);
	if (ctx == NULL)
		return NULL;
	FILE * f = (FILE *)ATOM_LOAD(&ctx->logfile);
	if (f) {
		// logfile may close in other thread
		if (ATOM_CAS_POINTER(&ctx->logfile, (uintptr_t)f, (uintptr_t)NULL)) { // 注意这行代码
			skynet_log_close(context, f, handle);
		}
	}
	skynet_context_release(ctx);
	return NULL;
}

-- debug_console.lua文件
skynet.start(function()
	local listen_socket, ip, port = socket.listen (ip, port)
	skynet.error("Start debug console at " .. ip .. ":" .. port)
	socket.start(listen_socket , function(id, addr)
		local function print(...)
			local t = { ... }
			for k,v in ipairs(t) do
				t[k] = tostring(v)
			end
			socket.write(id, table.concat(t,"\t"))
			socket.write(id, "\n")
		end
		socket.start(id)
		skynet.fork(console_main_loop, id , print, addr) -- 新建了一个新协程来执行命令
	end)
end)

-- debug_console控制台更详细的内容，以后会写道《Skynet使用之：console控制台》
-- 这里不再叙述

void 
skynet_log_output(FILE *f, uint32_t source, int type, int session, void * buffer, size_t sz) {
	if (type == PTYPE_SOCKET) {
		log_socket(f, buffer, sz);
	} else {
		uint32_t ti = (uint32_t)skynet_now();
		fprintf(f, ":%08x %d %d %u ", source, type, session, ti);
		log_blob(f, buffer, sz);
		fprintf(f,"\n");
		fflush(f);
	}
}