Added TurnOn Function to BuildServer (#1871)

Provide a way to re-enable a previously shutdown buildserver. This provides more granular control for buildservers behind a load balancer.

appinventor/buildserver/src/com/google/appinventor/buildserver/BuildServer.java

@@ -208,6 +208,7 @@ public class BuildServer {
   // otherwise still accepting jobs. This avoids having people get an error if the load
   // balancer sends a job our way because it hasn't decided we are down.
   private static volatile long shuttingTime = 0;
+  private static volatile long turningOnTime = 0;
 
   private static String shutdownToken = null;
 
@@ -218,7 +219,7 @@ public class BuildServer {
   //                DRAINING:   We have reached > 2/3 of max permitted jobs
   //                            We return bad health (but accept jobs) until
   //                            the number of active jobs is < 1/3 of max
-  private enum ShutdownState { UP, SHUTTING, DOWN, DRAINING };
+  private enum ShutdownState { UP, SHUTTING, TURNING, DOWN, DRAINING };
 
   private static volatile boolean draining = false; // We have exceeded 2/3 max load, waiting for
                                                     // the load to become < 1/3 max load
@@ -237,6 +238,9 @@ public class BuildServer {
     } else if (shut == ShutdownState.DRAINING) {
       LOG.info("Healthcheck: DRAINING");
       return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("Build Server is draining").build();
+    } else if (shut == ShutdownState.TURNING) {
+      LOG.info("Healthcheck: TURNING");
+      return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("Build Server is turning on").build();
     } else {
       LOG.info("Healthcheck: SHUTTING");
       return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("Build Server is shutting down").build();
@@ -256,6 +260,9 @@ public class BuildServer {
     if (shuttingTime != 0) {
       variables.put("shutdown-time", dateTimeFormat.format(new Date(shuttingTime)));
     }
+    if (turningOnTime != 0) {
+      variables.put("turnon-time", dateTimeFormat.format(new Date(turningOnTime)));
+    }
     variables.put("start-time", dateTimeFormat.format(new Date(runtimeBean.getStartTime())));
     variables.put("uptime-in-ms", runtimeBean.getUptime() + "");
     variables.put("vm-name", runtimeBean.getVmName());
@@ -345,6 +352,40 @@ public class BuildServer {
     }
   }
 
+  /**
+   * Indicate that the server is turning on.
+   *
+   * @param token -- secret token used like a password to authenticate the shutdown command
+   * @param delay -- the delay in seconds before jobs are no longer accepted
+   */
+
+  @GET
+  @Path("turnon")
+  @Produces(MediaType.TEXT_PLAIN)
+  public Response turnon(@QueryParam("token") String token, @QueryParam("delay") String delay) throws IOException {
+    if (commandLineOptions.shutdownToken == null || token == null) {
+      return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("No Shutdown Token").build();
+    } else if (!token.equals(commandLineOptions.shutdownToken)) {
+      return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("Invalid Shutdown Token").build();
+    } else {
+      if (shuttingTime == 0) {
+        return Response.status(Response.Status.FORBIDDEN).type(MediaType.TEXT_PLAIN_TYPE).entity("Buildserver is not expected to be shutted down").build();
+      }
+      long turnonTime = System.currentTimeMillis();
+      if (delay != null) {
+        try {
+          turnonTime += Integer.parseInt(delay) *1000;
+        } catch (NumberFormatException e) {
+          // XXX Ignore
+        }
+      }
+      turningOnTime = turnonTime;
+      DateFormat dateTimeFormat = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.FULL);
+      return Response.ok("ok: Will turnon at " + dateTimeFormat.format(new Date(turningOnTime)),
+          MediaType.TEXT_PLAIN_TYPE).build();
+    }
+  }
+
   /**
    * Build an APK file from the input zip file. The zip file needs to be a variant of the same
    * App Inventor source zip that's generated by the Download Source command.  The differences are
@@ -760,6 +801,11 @@ public class BuildServer {
   }
 
   private ShutdownState getShutdownState() {
+    if (turningOnTime != 0 && System.currentTimeMillis() > turningOnTime && turningOnTime > shuttingTime) {
+      turningOnTime = 0;
+      shuttingTime = 0;
+    }
+
     if (shuttingTime == 0) {
       int max = buildExecutor.getMaxActiveTasks();
       if (max < 10) {           // Only do this scheme if we are not unlimited
@@ -781,10 +827,12 @@ public class BuildServer {
       } else {
         return ShutdownState.UP;
       }
-    } else if (System.currentTimeMillis() > shuttingTime) {
-      return ShutdownState.DOWN;
-    } else {
+    } else if (turningOnTime >= System.currentTimeMillis()) {
+      return ShutdownState.TURNING;
+    } else if (shuttingTime >= System.currentTimeMillis()) {
       return ShutdownState.SHUTTING;
+    } else {
+      return ShutdownState.DOWN;
     }
   }
 }