/**
* attempts to resolve hostnameTarget from origin
*
* @return null if it definitively can't be resolved, best-effort IP address if possible, or blank
* if we could not run ssh or make sense of the output
*/
public static String getResolvedAddress(
Entity entity, SshMachineLocation origin, String hostnameTarget) {
ProcessTaskWrapper<Integer> task =
SshTasks.newSshExecTaskFactory(origin, "ping -c 1 -t 1 " + hostnameTarget)
.summary("checking resolution of " + hostnameTarget)
.allowingNonZeroExitCode()
.newTask();
DynamicTasks.queueIfPossible(task).orSubmitAndBlock(entity).asTask().blockUntilEnded();
if (task.asTask().isError()) {
log.warn(
"ping could not be run, at "
+ entity
+ " / "
+ origin
+ ": "
+ Tasks.getError(task.asTask()));
return "";
}
if (task.getExitCode() == null || task.getExitCode() != 0) {
if (task.getExitCode() != null && task.getExitCode() < 10) {
// small number means ping failed to resolve or ping the hostname
log.debug(
"not able to resolve "
+ hostnameTarget
+ " from "
+ origin
+ " for "
+ entity
+ " because exit code was "
+ task.getExitCode());
return null;
}
// large number means ping probably did not run
log.warn(
"ping not run as expected, at "
+ entity
+ " / "
+ origin
+ " (code "
+ task.getExitCode()
+ "):\n"
+ task.getStdout().trim()
+ " --- "
+ task.getStderr().trim());
return "";
}
String out = task.getStdout();
try {
String line1 = Strings.getFirstLine(out);
String ip = Strings.getFragmentBetween(line1, "(", ")");
if (Strings.isNonBlank(ip)) return ip;
} catch (Exception e) {
Exceptions.propagateIfFatal(e);
/* ignore non-parseable output */
}
if (out.contains("127.0.0.1")) return "127.0.0.1";
return "";
}
