Is there a way to restart nodes (for example Zolertia Z1) from within the code? I know there is a command which allows restarting through serial make z1-reset but is there any way to restart it from within the code ?
You can use watchdog for this purpose:
#include "dev/watchdog.h"
void do_reboot(void)
{
watchdog_reboot();
}
Related
I am trying to use the Golang SDK of Docker in order to maintain a slice variable with currently running containers on the local Docker instance. This slice is exported from a package and I want to use it to feed a web page.
I am not really used to goroutines and channels and that's why I am wondering if I have spotted a good solution for my problem.
I have a docker package as follows.
https://play.golang.org/p/eMmqkMezXZn
It has a Running variable containing the current state of running containers.
var Running []types.Container
I use a reload function to load the running containers in the Running variable.
// Reload the list of running containers
func reload() error {
...
Running, err = cli.ContainerList(context.Background(), types.ContainerListOptions{
All: false,
})
...
}
And then I start a goroutine from the init function to listen to Docker events and trigger the reload function accordingly.
func init() {
...
// Listen for docker events
go listen()
...
}
// Listen for docker events
func listen() {
filter := filters.NewArgs()
filter.Add("type", "container")
filter.Add("event", "start")
filter.Add("event", "die")
msg, errChan := cli.Events(context.Background(), types.EventsOptions{
Filters: filter,
})
for {
select {
case err := <-errChan:
panic(err)
case <-msg:
fmt.Println("reloading")
reload()
}
}
}
My question is, is it proper to update a variable from inside a goroutine (in terms of sync)? Maybe there is a cleaner way to achieve what I am trying to build?
Update
My concern here is not really about caching. It is more about hiding the "complexity" of the process of listening and update from the Docker SDK. I wanted to provide something like an index to easily let the end user loop and display currently running containers.
I was aware of data-races problems in threaded programs but I did not realize I was as actually in a context of concurrence here (I never wrote concurrent programs in Go before).
I effectively need to re-think the solution to be more idiomatic. As far as I can see, I have two options here: either protecting the variable with a mutex or re-thinking the design to integrate channels.
What means the most to me is to hide or encapsulate the method of synchronization used so the package users need not concern of how the shared state is protected.
Would you have any recommendations?
Thanks a lot for your help,
Loric
No, it is not idiomatic Go to share the Running variable between two goroutines. You do this by sharing it between the routine that runs your main function, and the listen function which is started with go—which spawns another goroutine.
Why, is because it breaks with
Do not communicate by sharing memory; instead, share memory by
communicating. ¹
So the design of the API needs to change in order to be idiomatic; you need to remove the Running variable and replace it with what? It depends on what you are trying to achieve. If you are trying to cache the cli.ContainerList because you need to call it often, and it might be expensive, you should implement a cache which is invalidated on each cli.Events.
What is your motivation?
I want to test the hello world application in a z1 mote. Unfortunately, when I try to visualize the results in the terminal using this command: make z1-reset & make login,
I always get an unreadable result:
����������������������������à������������������������������頲��
I run the test in Ubuntu 12.04 using contiki 2.7 and msp430-gcc 4.6.3
Are there any necessary drivers for zolertia z1 motes that I forgot to install?
Thanks in advance.
Best regards.
I faced the same problem a few weeks ago working on the Z1 ...what u should do is update the GCC-version to 4.7.0
You can follow these steps to upgrade the MSP430-gcc:
Update msp430 to version 4.7.0 follow http://wiki.contiki-os.org/doku.php?id=msp430x
After finish install msp430 version 4.7.0, move folder mspgccx from /opt/tmp/ to /opt/
Run export PATH=/opt/mspgccx/bin:$PATH on terminal for temporary, but for permanent need to put in bash_rc or bash_profile.
Then can compile contiki code.
Someone shared it with me and it did work for me..hope it works for you =) Read the steps carefully, it is a little tricky. Good luck.
It is possible the Z1 is already sending data over the USB port before the make login is finished and ready to receive, resulting in weird data. Try resetting the Z1 mote using a reset button or a on/off switch.
If that resets the login program, then you could try a LED example.
Or try below example that repeats the hello world message:
#include "contiki.h"
#include <stdio.h> /* For printf() */
PROCESS(hello_world_process, "Hello world process");
AUTOSTART_PROCESSES(&hello_world_process);
PROCESS_THREAD(hello_world_process, ev, data)
{
static struct etimer et;
PROCESS_BEGIN();
printf("First Hello world\n");
while(1){
//wait 1 second
etimer_set(&et, CLOCK_SECOND);
PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
printf("Hello world\n\n");
}
PROCESS_END();
}
On Solaris, processor_bind is used to set affinity for threads. You need to know the LWPID of the target thread or use the constant P_MYID to refer to yourself.
I have a function that looks like this:
void set_affinity(pthread_t thr, int cpu_number)
{
id_t lwpid = what_do_I_call_here(thr);
processor_bind(P_LWPID, lwpid, cpu_number, NULL);
}
In reality my function has a bunch of cross platform stuff in it that I've elided for clarity.
The key point is that I'd like to set the affinity of an arbitrary pthread_t so I can't use P_MYID.
How can I achieve this using processor_bind or an alternative interface?
Following up on this, and due to my confusion:
The lwpid is what is created by
pthread_create( &lwpid, NULL, some_func, NULL);
Thread data is available externally to a process that is not the one making the pthread_create() call - via the /proc interface
/proc/<pid>/lwp/<lwpid>/ lwpid == 1 is the main thread, 2 .. n are the lwpid in the above example.
But this tells you almost nothing about which thread you are dealing with, except that it is the lwpid in the example above.
/proc/pid/lwp/lwpid/lwpsinfo
can be read into a struct lwpsinfo which has some more information, from which you might be able to ascertain if you are looking at the thread you want. see /usr/include/sys/procfs.h
Or man -s 4 proc
The Solaris 11 kernel has critical threads optimization. You setup which threads require special care, the kernel does the rest. This appears to be what you want. Please read this short explanation to see if I understood what you want.
https://blogs.oracle.com/observatory/entry/critical_threads_optimization
The above is an alternate. It may not fly at all for you. But is the preferred mechanism, per Oracle.
For Solaris 10, use the pthread_t tid of the LWP with an idtype_t of P_LWPID in your call to processor_bind. This works in Solaris 8 -> 11. It works ONLY for LWP's in the process. It is not clear to me if that is your model.
HTH
I run the same code from two different locations in my application. I know it is the same code, because it is in a class and that class only has one publicly facing function. Both places call the function with the same arguments and both are running in the UI thread.
The function does a search for a particular printer by name using an asynchronous WMI query-->
var searcher =
new ManagementObjectSearcher(
"SELECT * from Win32_Printer WHERE Name LIKE '%ZDesigner GX430t'");
// Create an observer to trigger a callback when the search is completed.
var watcher = new ManagementOperationObserver();
watcher.Completed += PrinterSearchCompleted;
watcher.ObjectReady += PrinterSearchReady;
// Look for the printer
_printerFound = false;
_searchCompleted = false;
searcher.Get(watcher);
The problem I am having is that the ObjectReady event is not triggered when I run it from one location and when I run it from another, it get's triggered all the time.
Also, another problem is that this seems to be computer specific; some of the computers I run this on work just fine, others exhibit the problem I described above.
Any ideas what I should be looking for?
Couple of things to try:
Check if WMI service is running on all the computers.
Restart WMI service on the computers where it is not working.
You may find this article useful.
If its a Windows 7 or Windows Server 2008 R2 server, WMI has a memory leak problem. Check this.
I'm trying to stop a Windows service on a local machine (the service is Topshelf.Host, if that matters) with this code:
serviceController.Stop();
serviceController.WaitForStatus(ServiceControllerStatus.Stopped, timeout);
timeout is set to 1 hour, but service never actually gets stopped. Strange thing with it is that from within Services MMC snap-in I see it in "Stopping" state first, but after a while it reverts back to "Started". However, when I try to stop it manually, an error occurs:
Windows could not stop the Topshelf.Host service on Local Computer.
Error 1061: The service cannot accept control messages at this time.
Am I missing something here?
I know I am quite late to answer this but I faced a similar issue , i.e., the error: "The service cannot accept control messages at this time." and would like to add this as a reference for others.
You can try killing this service using powershell (run powershell as administrator):
#Get the PID of the required service with the help of the service name, say, service name.
$ServicePID = (get-wmiobject win32_service | where { $_.name -eq 'service name'}).processID
#Now with this PID, you can kill the service
taskkill /f /pid $ServicePID
Either your service is busy processing some big operation or is in transition to change the state. hence is not able to accept anymore input...just think of it as taking more than it can chew...
if you are sure that you haven't fed anything big to it, just go to task manager and kill the process for this service or restart your machine.
I had exact same problem with Topshelf hosted service. Cause was long service start time, more than 20 seconds. This left service in state where it was unable to process further requests.
I was able to reproduce problem only when service was started from command line (net start my_service).
Proper initialization for Topshelf service with long star time is following:
namespace Example.My.Service
{
using System;
using System.Threading.Tasks;
using Topshelf;
internal class Program
{
public static void Main()
{
HostFactory.Run(
x =>
{
x.Service<MyService>(
s =>
{
MyService testServerService = null;
s.ConstructUsing(name => testServerService = new MyService());
s.WhenStarted(service => service.Start());
s.WhenStopped(service => service.Stop());
s.AfterStartingService(
context =>
{
if (testServerService == null)
{
throw new InvalidOperationException("Service not created yet.");
}
testServerService.AfterStart(context);
});
});
x.SetServiceName("my_service");
});
}
}
public sealed class MyService
{
private Task starting;
public void Start()
{
this.starting = Task.Run(() => InitializeService());
}
private void InitializeService()
{
// TODO: Provide service initialization code.
}
[CLSCompliant(false)]
public void AfterStart(HostControl hostStartedContext)
{
if (hostStartedContext == null)
{
throw new ArgumentNullException(nameof(hostStartedContext));
}
if (this.starting == null)
{
throw new InvalidOperationException("Service start was not initiated.");
}
while (!this.starting.Wait(TimeSpan.FromSeconds(7)))
{
hostStartedContext.RequestAdditionalTime(TimeSpan.FromSeconds(10));
}
}
public void Stop()
{
// TODO: Provide service shutdown code.
}
}
}
I've seen this issue as well, specifically when a service is start pending and I send it a stop programmatically which succeeds but does nothing. Also sometimes I see stop commands to a running service fail with this same exception but then still actually stop the service. I don't think the API can be trusted to do what it says. This error message explanation is quite helpful...
http://technet.microsoft.com/en-us/library/cc962384.aspx
I run into a similar issue and found out it was due to one of the services getting stuck in a state of start-pending, stop pending, or stopped.
Rebooting the server or trying to restart services did not work.
To solve this, I run the Task Manager in the server and in the "Details" tab I located the services that were stuck and killed the process by ending the task. After ending the task I was able to restart services without problem.
In brief:
1. Go to Task Manager
2. Click on "Detail" tab
3. Locate your service
4. Right click on it and stop/kill the process.
That is it.
I know it was opened while ago, but i am bit missing the option with Windows command prompt, so only for sake of completeness
Open Task Manager and find respective process and its PID i.e PID = 111
Eventually you can narrow down the executive file i.e. Image name = notepad.exe
in command prompt use command TASKKILL
example: TASKKILL /F /PID 111 ; TASKKILL /F /IM notepad.exe
I had this exact issue internally when starting and stopping a service using PowerShell (Via Octopus Deploy). The root cause for the service not responding to messages appeared to be related to devs accessing files/folders within the root service install directory via an SMB connection (looking at a config file with notepad/explorer).
If the service gets stuck in that situation then the only option is to kill it and sever the connections using computer management. After that, service was able to be redeployed fine.
May not be the exact root cause, but something we now check for.
I faced the similar issue. This error sometimes occur because the service can no longer accept control messages, this may be due to disk space issues in the server where that particular service's log file is present.
If this occurs, you can consider the below option as well.
Go to the location where the service exe & its log file is located.
Free up some space
Kill the service's process via Task manager
Start the service.
I just fought this problem while moving code from an old multi partition box to a newer single partition box. On service stop I was writing to D: and since it didn't exist anymore I got a 1061 error. Any long operation during the OnStop will cause this though unless you spin the call off to another thread with a callback delegate.