Merge pull request #4031 from daniel-beck/agent-secret-file

Add an example how to launch agent with secret not on command line

core/src/main/resources/hudson/slaves/JNLPLauncher/main.jelly

@@ -80,6 +80,11 @@ THE SOFTWARE.
                 </p>
                 <!-- TODO conceal secret w/ JS if possible -->
                 <pre>java${it.launcher.vmargs == null ? '' : ' ' + it.launcher.vmargs} -jar <a href="${rootURL}/jnlpJars/agent.jar">agent.jar</a> -jnlpUrl ${h.inferHudsonURL(request)}${it.url}slave-agent.jnlp -secret ${it.jnlpMac} ${it.launcher.getWorkDirOptions(it)}</pre>
+                <p>
+                  ${%Run from agent command line, with the secret stored in a file:}
+                </p>
+                <pre>echo ${it.jnlpMac} > secret-file
+java${it.launcher.vmargs == null ? '' : ' ' + it.launcher.vmargs} -jar <a href="${rootURL}/jnlpJars/agent.jar">agent.jar</a> -jnlpUrl ${h.inferHudsonURL(request)}${it.url}slave-agent.jnlp -secret @secret-file ${it.launcher.getWorkDirOptions(it)}</pre>
               </li>
             </j:otherwise>
           </j:choose>