1 files changed, 52 insertions, 0 deletions
diff --git a/R/pkg/inst/worker/daemon.R b/R/pkg/inst/worker/daemon.R
new file mode 100644
index 0000000000..3584b418a7
--- /dev/null
+++ b/R/pkg/inst/worker/daemon.R
@@ -0,0 +1,52 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Worker daemon
+
+rLibDir <- Sys.getenv("SPARKR_RLIBDIR")
+script <- paste(rLibDir, "SparkR/worker/worker.R", sep = "/")
+
+# preload SparkR package, speedup worker
+.libPaths(c(rLibDir, .libPaths()))
+suppressPackageStartupMessages(library(SparkR))
+
+port <- as.integer(Sys.getenv("SPARKR_WORKER_PORT"))
+inputCon <- socketConnection(port = port, open = "rb", blocking = TRUE, timeout = 3600)
+
+while (TRUE) {
+  ready <- socketSelect(list(inputCon))
+  if (ready) {
+    port <- SparkR:::readInt(inputCon)
+    # There is a small chance that it could be interrupted by signal, retry one time
+    if (length(port) == 0) {
+      port <- SparkR:::readInt(inputCon)
+      if (length(port) == 0) {
+        cat("quitting daemon\n")
+        quit(save = "no")
+      }
+    }
+    p <- parallel:::mcfork()
+    if (inherits(p, "masterProcess")) {
+      close(inputCon)
+      Sys.setenv(SPARKR_WORKER_PORT = port)
+      source(script)
+      # Set SIGUSR1 so that child can exit
+      tools::pskill(Sys.getpid(), tools::SIGUSR1)
+      parallel:::mcexit(0L)
+    }
+  }
+}