f44e6e9639
To avoid races between the lwIP callbacks (lwIP RTOS task) and the Lua handlers (LVM RTOS task), the data flow and ownership has been simplified and cleaned up. lwIP callbacks now have no visibility of the userdata struct. They are limited to creating small event objects and task_post()ing them over to the LVM "thread", passing ownership in doing so. The shared identifier then becomes the struct netconn*. On the LVM side, we keep a linked list of active userdata objects. This allows us to retrieve the correct userdata when we get an event with a netconn pointer. Because this list is only ever used within the LVM task, no locking is necessary. The old approach of stashing a userdata pointer into the 'socket' field on the netconn has been removed entirely, as this was both not thread/RTOS-task safe, and also interfered with the IDFs internal use of the socket field (even when using only the netconn layer). As an added benefit, this removed the need for all the SYS_ARCH_PROTECT() locking stuff. The need to track receive events before the corresponding userdata object has been established has been removed by virtue of not reordering the "accept" and the "recv" events any more (previously accepts were posted with medium priority, while the receives where high priority, leading to the observed reordering and associated headaches). The workaround for IDF issue 784 has been removed as it is now not needed and is in fact directly harmful as it results in a double-free. Yay for getting rid of old workarounds! DNS resolution code paths were merged for the two instances of "socket" initiated resolves (connect/dns functions). Also fixed an instance of using a stack variable for receiving the resolved IP address, with said variable going out of scope before the DNS resolution necessarily completed (hello, memory corruption!). Where possible, moved to use the Lua allocator rather than plain malloc. Finally, the NodeMCU task posting mechanism got a polish and an adjustment. Given all the Bad(tm) that tends to happen if something fails task posting, I went through a couple of iterations on how to avoid that. Alas, the preferred solution of blocking non-LVM RTOS tasks until a slot is free turned out to not be viable, as this easily resulted in deadlocks with the lwIP stack. After much deliberation I settled on increasing the number of available queue slots for the task_post() mechanism, but in the interest of user control also now made it user configurable via Kconfig. |
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| components | ||
| docs | ||
| examples | ||
| lua_compat | ||
| lua_examples | ||
| lua_modules | ||
| sdk | ||
| tools | ||
| .gitignore | ||
| .gitmodules | ||
| .travis.yml | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| mkdocs.yml | ||
| sdkconfig.defaults | ||
README.md
NodeMCU on ESP32
A Lua based firmware for ESP32 WiFi SOC
NodeMCU is an eLua based firmware for the ESP32 WiFi SOC from Espressif. The firmware is based on the Espressif IoT Development Framework and uses a file system based on spiffs. The code repository consists of 98.1% C-code that glues the thin Lua veneer to the SDK.
The NodeMCU firmware is a companion project to the popular NodeMCU dev kits, ready-made open source development boards with ESP8266-12E chips.
Summary
- Easy to program wireless node and/or access point
- Based on Lua 5.1.4 (without debug, os modules)
- Asynchronous event-driven programming model
- 10+ built-in modules
- Firmware available with or without floating point support (integer-only uses less memory)
- Up-to-date documentation at https://nodemcu.readthedocs.io
Programming Model
The NodeMCU programming model is similar to that of Node.js, only in Lua. It is asynchronous and event-driven. Many functions, therefore, have parameters for callback functions. To give you an idea what a NodeMCU program looks like study the short snippets below. For more extensive examples have a look at the /lua_examples folder in the repository on GitHub.
-- a simple HTTP server
srv = net.createServer(net.TCP)
srv:listen(80, function(conn)
conn:on("receive", function(sck, payload)
print(payload)
sck:send("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<h1> Hello, NodeMCU.</h1>")
end)
conn:on("sent", function(sck) sck:close() end)
end)
-- connect to WiFi access point
wifi.mode(wifi.STATION, true)
wifi.sta.on("connected", function() print("connected") end)
wifi.sta.on("got_ip", function(event, info) print("got ip "..info.ip) end)
-- mandatory to start wifi after reset
wifi.start()
wifi.sta.config({ssid="SSID", pwd="password", auto=true}, true)
Documentation
The entire NodeMCU documentation is maintained right in this repository at /docs. The fact that the API documentation is maintained in the same repository as the code that provides the API ensures consistency between the two. With every commit the documentation is rebuilt by Read the Docs and thus transformed from terse Markdown into a nicely browsable HTML site at https://nodemcu.readthedocs.io/en/dev-esp32/.
- How to build the firmware
- How to flash the firmware
- How to upload code and NodeMCU IDEs
- API documentation for every module
Support
See https://nodemcu.readthedocs.io/en/dev/en/support/.