X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=results.arch.tex;h=e276010256cde2039deb9ff02951a53837b7a54e;hb=c91e99cb9e71060f461c03d1454ad5f31e9495a1;hp=fde75c0cae261424f38ed47594e836858210bea5;hpb=d118ff9d857683084065145df45135ef6fa06711;p=msc-thesis1617.git diff --git a/results.arch.tex b/results.arch.tex index fde75c0..e276010 100644 --- a/results.arch.tex +++ b/results.arch.tex @@ -1,13 +1,46 @@ +\section{Overview \& Terminology} +The goal of the architecture is to facilitate an ecosystem in which an +\gls{iTasks}-system can add, change and remove devices at runtime. Moreover, +the \gls{iTasks}-system can send \glspl{mTask}, compiled at runtime to +bytecode, to the device. The device runs an interpreter which can execute the +\gls{Task}'s bytecode. Devices are persistent during reboots of the +\gls{iTasks}-system. The methods of interacting with \glspl{mTask} is analogous +to interacting with \gls{iTasks}-\glspl{Task} and programmers can access the +\glspl{SDS} made for a device in the same way as a regular \glspl{SDS}. The +following terms will be used throughout the architecture description. + +\begin{itemize} + \item Device, Client + + This is the actual device connected to the system. This can be a real + device such as a microcontroller but also just a program on the same + machine as the server. + \item Server, \gls{iTasks}-System + + The actual executable serving the \gls{iTasks} interfaces. The system + will contain \glspl{Task} taking care of the communication with the + clients. + \item System + + The complete ecosystem, thus containing both the server and client + programs. + \item Engine + + The runtime system of the client. This system handles the communication + with the server and interprets the \glspl{Task}. +\end{itemize} + + \section{Devices} -The client code for the devices is compiled from one codebase. For a device to -be eligible for \glspl{mTask} it must be able to compile the shared codebase +The engine for the devices is compiled from one codebase. For a device to +be eligible for \glspl{mTask}, it must be able to compile the shared codebase and implement (part of) the device specific interface. The shared codebase only uses standard \gls{C} and no special libraries or tricks are used. Therefore the code is compilable for almost any device or system. Note that it is not -needed to implement a full interface. The full interface excluding the device -specific settings is listed in Appendix~\ref{app:device-interface}. The -interface works in a similar fashion as the \gls{EDSL}. Devices do not have to -implement all functionality, this is analogous to the fact that views do not +needed to implement a full interface. The full interface --- excluding the +device specific settings --- is listed in Appendix~\ref{app:device-interface}. +The interface works in a similar fashion as the \gls{EDSL}. Devices do not have +to implement all functionality, this is analogous to the fact that views do not have to implement all type classes in the \gls{EDSL}. When the device connects for the first time with a server the specifications of what is implemented is communicated. @@ -22,49 +55,66 @@ the device software. This is tested in particular on the \texttt{STM32f7x} series \gls{ARM} development board. - \item Microcontrollers programmable by the \emph{Arduino} \gls{IDE}.\\ + \item Microcontrollers programmable by the \gls{Arduino} \gls{IDE}.\\ - This does not only include \emph{Arduino} compatible boards but also - other boards capable of running \emph{Arduino} code. The code + This does not only include \gls{Arduino} compatible boards but also + other boards capable of running \gls{Arduino} code. The code has been found working on the \texttt{ESP8266} powered \emph{NodeMCU}. - It is tested on devices as small as the regular \emph{Arduino UNO} - board that only boasts a meager \emph{2K} of \emph{RAM}. + It is tested on devices as small as the regular \gls{Arduino} + \emph{UNO} board that only boasts a meager \emph{2K} of \emph{RAM}. \end{itemize} \section{Specification} -Devices are stored in a record type and all devices in the system are stored in -a \gls{SDS} containing all devices. From the macro settings in the interface -file a profile is created for the device that describes the specification. When -a connection between the server and a client is established the server will -send a request for specification. The client will serialize his specification -and send it to the server so that the server knows what the client is capable -of. The exact specification is listed in Listing~\ref{lst:devicespec} - -\begin{lstlisting}[language=Clean,label={lst:devicespec}, +The server stores a description for every device available in a record type +which are stored in a \gls{SDS}. From the macro settings in +the interface file, a profile is created for the device that describes the +specification. When a connection between the server and a client is established +the server will send a request for specification. The client will serialize his +specification and send it to the server so that the server knows what the +client is capable of. The exact specification is shown in +Listing~\ref{lst:devicespec} + +\begin{lstlisting}[label={lst:devicespec}, caption={Device specification for \glspl{mTask}}] :: MTaskDeviceSpec = - {haveLed :: Bool - ,haveAio :: Bool - ,haveDio :: Bool - ,bytesMemory :: Int + { haveLed :: Bool + , haveAio :: Bool + , haveDio :: Bool + , bytesMemory :: Int } \end{lstlisting} -\section{Communication} -The communication to and fro a device runs via a single \gls{SDS}. Every -device has a specific resource that is used to connect to the device. The -current system supports connecting devices via a serial connection and via a -\gls{TCP} connection. Every device has the type \CI{MTaskDevice} and which -is listed in Listing~\ref{lst:mtaskdevice}. When a device is added a background -task is started that runs the \CI{synFun}. The \CI{synFun} is the task that -synchronizes the channel \gls{SDS} with the actual device. For the \gls{TCP} -device this is a simple \CI{tcpconnect}. The \CI{TaskId} of the background task -is saved to be able to stop the task in the future. When the task is unable to -connect it will set the \CI{deviceError} field to notify the user. -\todo{netter maken} - -\begin{lstlisting}[language=Clean,caption={Device type},label={lst:mtaskdevice}] +\section{Device Storage} +All devices available in the system are stored in a big \gls{SDS} that contains +a list of \CI{MTaskDevice}s. The exact specification is defined as in +Listing~\ref{lst:mtaskdevice} with the accompanying classes and types. + +The \CI{deviceResource} component of the record must implement the +\CI{MTaskDuplex} interface that provides a function that launches a \gls{Task} +used for synchronizing the channels. The \CI{deviceTask} stores the +\gls{Task}-id for this \gls{Task} when active so that it can be checked upon. +This top-level task has the duty to report exceptions and errors as they are +thrown by setting the \CI{deviceError} field. All communication goes via these +channels. If the system wants to send a message to the device, it just puts it +in the channels. Messages sent from the client to the server are also placed +in there. In the case of the \gls{TCP} device type, the \gls{Task} is just a +simple wrapper around the existing \CI{tcpconnect} function in \gls{iTasks}. In +case of a device connected by a serial connection, it uses the newly developed +serial port library of \gls{Clean}\footnote{\url{% +https://gitlab.science.ru.nl/mlubbers/CleanSerial}}. + +Besides all the communication information, the record also keeps track of the +\glspl{Task} currently on the device, the compiler state (see +Section~\ref{sec:compiler}) and the according \glspl{SDS}. Finally, it stores +the specification of the device that is received when connecting. All of this +is given in Listing~\ref{lst:mtaskdevice}. The definitions of the message +format are explained in the following section. + +\begin{lstlisting}[caption={Device type},label={lst:mtaskdevice}] +deviceStoreNP :: Shared [MTaskDevice] + :: Channels :== ([MTaskMSGRecv], [MTaskMSGSend], Bool) +:: BCState = ... // Compiler state, explained in later sections :: MTaskResource = TCPDevice TCPSettings | SerialDevice TTYSettings @@ -73,11 +123,145 @@ connect it will set the \CI{deviceError} field to notify the user. , deviceError :: Maybe String , deviceChannels :: String , deviceName :: String + , deviceState :: BCState , deviceTasks :: [MTaskTask] , deviceData :: MTaskResource , deviceSpec :: Maybe MTaskDeviceSpec + , deviceShares :: [MTaskShare] } +channels :: MTaskDevice -> Shared Channels + class MTaskDuplex a where synFun :: a (Shared Channels) -> Task () \end{lstlisting} + +\section{Communication} +The communication from the server to the client and vice versa is just a +character stream containing encoded \gls{mTask} messages. The specific encoding +is visible in Appendix~\ref{app:communication-protocol}. The type holding the +messages in Listing~\ref{lst:avmsg}. Detailed explaination about the message +types will be given in the following subsections. + +\begin{lstlisting}[label={lst:avmsg},caption={Available messages}] +:: MTaskId :== Int +:: MSDSId :== Int +:: MTaskFreeBytes :== Int +:: MTaskMSGRecv + = MTTaskAck MTaskId MTaskFreeBytes | MTTaskDelAck MTaskId + | MTSDSAck MSDSId | MTSDSDelAck MSDSId + | MTPub MSDSId BCValue | MTMessage String + | MTDevSpec MTaskDeviceSpec | MTEmpty + +:: MTaskMSGSend + = MTTask MTaskInterval String | MTTaskDel MTaskId + | MTShutdown | MTSds MSDSId BCValue + | MTUpd MSDSId BCValue | MTSpec + +:: MTaskInterval = OneShot | OnInterval Int | OnInterrupt Int +\end{lstlisting} + +\subsection{Add a device} +A device can be added by filling in the \CI{MTaskDevice} record as much as +possible and running the \CI{connectDevice} function. This function grabs the +channels, starts the synchronization \gls{Task}, makes sure the errors are +handled when needed and runs a processing function in parallel to react on the +incoming messages. Moreover, it sends a specification request to the device in +question to determine the details of the device and updates the record to +contain the top-level \gls{Task}-id. All the device functionality heavily +depends on the \CI{withDevices} function that applies a function a device in +the \gls{SDS} when they are equal. Device equality is defined as equality on +their channels. This allows you to give an old device record to the function +and still update the latest instance. Listing~\ref{lst:connectDevice} shows the +connection function. + +\begin{lstlisting}[label={lst:connectDevice},% + caption={Connect a device}] +withDevices :: MTaskDevice (MTaskDevice -> MTaskDevice) -> Task [MTaskDevice] + +connectDevice :: (MTaskDevice (Shared Channels) -> Task ()) MTaskDevice -> Task Channels +connectDevice procFun device = let ch = channels device + in appendTopLevelTask 'DM'.newMap True + (procFun device ch -||- catchAll (getSynFun d.deviceData ch) errHdl) + >>= \tid->withDevices device (\d->{d&deviceTask=Just tid,deviceError=Nothing}) + >>| upd (\(r,s,ss)->(r,s++[MTSpec],ss)) ch + where + errHdl e = withDevices device (\d->{d & deviceTask=Nothing, deviceError=Just e}) @! () +\end{lstlisting} + +Figure~\ref{fig:handshake} shows the connection diagram. The client responds to +the server with their device specification. This is detected by the processing +function and the record is updated accordingly. + +\begin{figure}[H] + \centering + \begin{sequencediagram} + \newthread{s}{Server} + \newinst[4]{c}{Client} + \begin{call}{s}{MTSpec}{c}{MTDevSpec} + \end{call} + \end{sequencediagram} + \caption{Connect a device}\label{fig:handshake} +\end{figure} + +\subsection{\glspl{Task} \& \glspl{SDS}} +When a \gls{Task} is sent to the device it is added to the device record +without an identifier. The actual identifier is added to the record when the +acknowledgement of the \gls{Task} by the device is received. The connection +diagram is shown in Figure~\ref{fig:tasksend}. + +\begin{figure}[H] + \centering + \begin{sequencediagram} + \newthread{s}{Server} + \newinst[4]{c}{Client} + \begin{call}{s}{MTSDS}{c}{MTSDSAck} + \end{call} + \begin{call}{s}{MTTask}{c}{MTTaskAck} + \end{call} + \end{sequencediagram} + \caption{Sending a \gls{Task} to a device}\label{fig:tasksend} +\end{figure} + +The function for sending a \gls{Task} to the device is shown in +Listing~\ref{lst:sendtask}. First the \gls{Task} is compiled into messages. The +details of the compilation process are given in Section~\ref{sec:compiler}. +The new \glspl{SDS} that were made during compilation are added to the +deviceshares that were made during the compilation are merged with the existing +shares on the device. Furthermore the messages are placed in the channel share +of the device. This will result in sending the actual \gls{SDS} specification +and \gls{Task} specifications to the device. A \gls{Task} record is created +with the identifier $-1$ to denote a \gls{Task} not yet acknowledged. Finally +the device itself is updated with the new state and with the new \gls{Task}. +When the device returns an acknowledgement the \gls{Task} is updated +accordingly. + +\begin{lstlisting}[label={lst:sendtask},% + caption={Sending a \gls{Task} to a device}] +makeTask :: String Int -> Task MTaskTask +makeTask name ident = get currentDateTime @ \dt->{MTaskTask | name=name, ident=ident, dateAdded=dt} + +makeShare :: String Int BCValue -> MTaskShare +makeShare withTask identifier value = {MTaskShare | withTask=[withTask], identifier=identifier, value=value} + +sendTaskToDevice :: String (Main (ByteCode a Stmt)) (MTaskDevice, MTaskInterval) -> Task [MTaskDevice] +sendTaskToDevice wta mTask (device, timeout) +# (msgs, newState) = toMessages timeout mTask device.deviceState +# shares = [makeShare wta sdsi sdsval\\{sdsi,sdsval}<-newState.sdss, (MTSds sdsi` _)<-msgs | sdsi == sdsi`] += updateShares device ((++) shares) + >>| sendMessages msgs device + >>| makeTask wta -1 + >>= withDevices device o addTaskUpState newState + where + addTaskUpState :: BCState MTaskTask MTaskDevice -> MTaskDevice + addTaskUpState st task device = {MTaskDevice | device & + deviceState=st, deviceTasks=[task:device.deviceTasks]} +\end{lstlisting} + +\subsection{Miscellaneous Messages} +There exists one special type of message that is sent to the device only when +it needs to reboot. When the server wants to stop the bond with the device it +sends the \CI{MTShutdown} message. The device will then clear his memory, thus +losing all the \glspl{SDS} and \glspl{Task} that were stored and reset itself. +Shortly after the shutdown message a new server can connect to the device +because the device is back in listening mode.