// invokeEventScript will execute the given event script with the given
// event. Depending on the event, the semantics of how data are passed
// are a bit different. For all events, the SERF_EVENT environmental
// variable is the type of the event. For user events, the SERF_USER_EVENT
// environmental variable is also set, containing the name of the user
// event that was fired.
//
// In all events, data is passed in via stdin to faciliate piping. See
// the various stdin functions below for more information.
func invokeEventScript(logger *log.Logger, script string, self serf.Member, event serf.Event) error {
defer metrics.MeasureSince([]string{"agent", "invoke", script}, time.Now())
var output bytes.Buffer
// Determine the shell invocation based on OS
var shell, flag string
if runtime.GOOS == windows {
shell = "cmd"
flag = "/C"
} else {
shell = "/bin/sh"
flag = "-c"
}
cmd := exec.Command(shell, flag, script)
cmd.Env = append(os.Environ(),
"SERF_EVENT="+event.EventType().String(),
"SERF_SELF_NAME="+self.Name,
"SERF_SELF_ROLE="+self.Tags["role"],
)
cmd.Stderr = &output
cmd.Stdout = &output
// Add all the tags
for name, val := range self.Tags {
tag_env := fmt.Sprintf("SERF_TAG_%s=%s", strings.ToUpper(name), val)
cmd.Env = append(cmd.Env, tag_env)
}
stdin, err := cmd.StdinPipe()
if err != nil {
return err
}
switch e := event.(type) {
case serf.MemberEvent:
go memberEventStdin(logger, stdin, &e)
case serf.UserEvent:
cmd.Env = append(cmd.Env, "SERF_USER_EVENT="+e.Name)
cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_USER_LTIME=%d", e.LTime))
go streamPayload(logger, stdin, e.Payload)
case *serf.Query:
cmd.Env = append(cmd.Env, "SERF_QUERY_NAME="+e.Name)
cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_QUERY_LTIME=%d", e.LTime))
go streamPayload(logger, stdin, e.Payload)
default:
return fmt.Errorf("Unknown event type: %s", event.EventType().String())
}
if err := cmd.Start(); err != nil {
return err
}
err = cmd.Wait()
logger.Printf("[DEBUG] agent: Event '%s' script output: %s",
event.EventType().String(), output.String())
if err != nil {
return err
}
// If this is a query and we have output, respond
if query, ok := event.(*serf.Query); ok && len(output.Bytes()) > 0 {
if err := query.Respond(output.Bytes()); err != nil {
logger.Printf("[WARN] agent: Failed to respond to query '%s': %s",
event.String(), err)
}
}
return nil
}
// invokeEventScript will execute the given event script with the given
// event. Depending on the event, the semantics of how data are passed
// are a bit different. For all events, the SERF_EVENT environmental
// variable is the type of the event. For user events, the SERF_USER_EVENT
// environmental variable is also set, containing the name of the user
// event that was fired.
//
// In all events, data is passed in via stdin to faciliate piping. See
// the various stdin functions below for more information.
func invokeEventScript(logger *log.Logger, script string, self serf.Member, event serf.Event) error {
defer metrics.MeasureSince([]string{"agent", "invoke", script}, time.Now())
output, _ := circbuf.NewBuffer(maxBufSize)
// Determine the shell invocation based on OS
var shell, flag string
if runtime.GOOS == windows {
shell = "cmd"
flag = "/C"
} else {
shell = "/bin/sh"
flag = "-c"
}
cmd := exec.Command(shell, flag, script)
cmd.Env = append(os.Environ(),
"SERF_EVENT="+event.EventType().String(),
"SERF_SELF_NAME="+self.Name,
"SERF_SELF_IP="+self.Addr.String(),
"SERF_SELF_PORT="+fmt.Sprintf("%v", self.Port),
"SERF_SELF_ROLE="+self.Tags["role"],
)
cmd.Stderr = output
cmd.Stdout = output
// Add all the tags
for name, val := range self.Tags {
//http://stackoverflow.com/questions/2821043/allowed-characters-in-linux-environment-variable-names
//(http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html for the long version)
//says that env var names must be in [A-Z0-9_] and not start with [0-9].
//we only care about the first part, so convert all chars not in [A-Z0-9_] to _
sanitizedName := sanitizeTagRegexp.ReplaceAllString(strings.ToUpper(name), "_")
tag_env := fmt.Sprintf("SERF_TAG_%s=%s", sanitizedName, val)
cmd.Env = append(cmd.Env, tag_env)
}
stdin, err := cmd.StdinPipe()
if err != nil {
return err
}
switch e := event.(type) {
case serf.MemberEvent:
go memberEventStdin(logger, stdin, &e)
case serf.UserEvent:
cmd.Env = append(cmd.Env, "SERF_USER_EVENT="+e.Name)
cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_USER_LTIME=%d", e.LTime))
go streamPayload(logger, stdin, e.Payload)
case *serf.Query:
cmd.Env = append(cmd.Env, "SERF_QUERY_NAME="+e.Name)
cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_QUERY_LTIME=%d", e.LTime))
go streamPayload(logger, stdin, e.Payload)
default:
return fmt.Errorf("Unknown event type: %s", event.EventType().String())
}
// Start a timer to warn about slow handlers
slowTimer := time.AfterFunc(warnSlow, func() {
logger.Printf("[WARN] agent: Script '%s' slow, execution exceeding %v",
script, warnSlow)
})
if err := cmd.Start(); err != nil {
return err
}
// Warn if buffer is overritten
if output.TotalWritten() > output.Size() {
logger.Printf("[WARN] agent: Script '%s' generated %d bytes of output, truncated to %d",
script, output.TotalWritten(), output.Size())
}
err = cmd.Wait()
slowTimer.Stop()
logger.Printf("[DEBUG] agent: Event '%s' script output: %s",
event.EventType().String(), output.String())
if err != nil {
return err
}
// If this is a query and we have output, respond
if query, ok := event.(*serf.Query); ok && output.TotalWritten() > 0 {
if err := query.Respond(output.Bytes()); err != nil {
logger.Printf("[WARN] agent: Failed to respond to query '%s': %s",
event.String(), err)
}
}
return nil
}
