API toolkit for Supervisor written in Go!
Listener implements a Supervisor event listener. The following code illustrates basic usage of the listener:
func main() {
done := make(chan bool)
events := make(chan supervisor.Event)
evl := supervisor.NewListener(os.Stdin, os.Stdout)
go func() {
for event := range events {
fmt.Fprintf(os.Stderr, "Got event: %s\n", event)
}
done <- true
}()
evl.Run(events)
close(events)
<-done
}
Client implements an HTML RPC client to communicate with Supervisor. The following code demonstrates using the client to start a service:
func main() {
client, err := supervisor.NewClient("http://localhost:9001/RPC2")
if err != nil {
fmt.Printf("Error: %s\n", err)
os.Exit(1)
}
if result, err = client.StartProcess("nginx", true); err != nil {
fmt.Printf("Error: %s\n", err)
os.Exit(1)
} else if !result {
fmt.Printf("Failed to start process.\n")
}
fmt.Printf("Process started.\n")
}
Monitor implements a stateful monitoring system. It maintains the current state of all processes and emits events when processes are added, removed, or change state. It will also emit events when the Supervisor instance changes state. It will also do a full state refresh on any TICK event it receives. For full functionality it requires the PROCESS_STATE, SUPERVISOR_STATE_CHANGE, and a TICK event. If the TICK event is removed then no events will be emitted for process removal.
As an example:
func main() {
url := "http://localhost:9001/RPC2"
events := make(chan interface{})
mon, err := supervisor.NewMonitor(url, os.Stdin, os.Stdout, events)
if err != nil {
fmt.Fprintf(os.Stderr, "Error: %s\n", err)
os.Exit(1)
}
done := make(chan bool)
go func() {
for event := range events {
switch event.(type) {
case supervisor.ProcessAddEvent:
process := (event.(supervisor.ProcessAddEvent)).Process
fmt.Fprintf(os.Stderr, "Process %s added\n", process.Name)
case supervisor.ProcessRemoveEvent:
process := (event.(supervisor.ProcessRemoveEvent)).Process
fmt.Fprintf(os.Stderr, "Process %s added\n", process.Name)
case supervisor.ProcessStateEvent:
process := (event.(supervisor.ProcessStateEvent)).Process
from := (event.(supervisor.ProcessStateEvent)).FromState
fmt.Fprintf(os.Stderr, "Process %s state change %s => %s\n", process.Name, from, process.State)
case supervisor.SupervisorStateEvent:
supervisor := (event.(supervisor.SupervisorStateEvent)).Supervisor
from := (event.(supervisor.SupervisorStateEvent)).FromState
fmt.Fprintf(os.Stderr, "Supervisor \"%s\" state change %s => %s\n", supervisor.Name, from, supervisor.State)
default:
fmt.Fprintf(os.Stderr, "Unchecked Event: %+v\n", event)
}
}
done <- true
}()
mon.Refresh()
mon.Run()
close(events)
mon.Close()
<- done
}
This software project is licensed under the BSD-derived license and is copyright (c) 2013 Ryan Bourgeois. A copy of the license is included in the LICENSE file. If it is missing a copy can be found on the project page.