diff --git a/arcanist_util/config/FacebookArcanistConfiguration.php b/arcanist_util/config/FacebookArcanistConfiguration.php
index f0f9653a2..d82f9a873 100644
--- a/arcanist_util/config/FacebookArcanistConfiguration.php
+++ b/arcanist_util/config/FacebookArcanistConfiguration.php
@@ -3,204 +3,34 @@
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
+
+require('RocksDBCommonHelper.php');
+
+define("DIFF_COMMAND", "diff");
+
 class FacebookArcanistConfiguration extends ArcanistConfiguration {
 
   public function didRunWorkflow($command,
                                  ArcanistWorkflow $workflow,
                                  $error_code) {
-    if ($command == 'diff' && !$workflow->isRawDiffSource()) {
-      $this->startTestsInSandcastle($workflow);
-    }
-  }
+    // Default options don't terminate on failure, but that's what we want. In
+    // the current case we use assertions intentionally as "terminate on failure
+    // invariants".
+    assert_options(ASSERT_BAIL, true);
 
-  //////////////////////////////////////////////////////////////////////
-  /*  Run tests in sandcastle */
-  function postURL($diffID, $url) {
-    $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
-           . '"name":"click here for sandcastle tests for D' . $diffID . '", '
-           . '"link":"' . $url . '"}\' | '
-           . 'http_proxy=fwdproxy.any.facebook.com:8080 '
-           . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
-           . 'differential.updateunitresults';
-    shell_exec($cmd);
-  }
+    assert($workflow);
+    assert(strlen($command) > 0);
 
-  function updateTestCommand($diffID, $test, $status) {
-    $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
-           . '"name":"' . $test . '", '
-           . '"result":"' . $status . '"}\' | '
-           . 'http_proxy=fwdproxy.any.facebook.com:8080 '
-           . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
-           . 'differential.updateunitresults';
-    return $cmd;
-  }
+    if ($command == DIFF_COMMAND && !$workflow->isRawDiffSource()) {
+      $diffID = $workflow->getDiffId();
 
-  function updateTest($diffID, $test) {
-    shell_exec($this->updateTestCommand($diffID, $test, "waiting"));
-  }
-
-  function getSteps($diffID, $username, $test) {
-    $arcrc_content = exec("cat ~/.arcrc | gzip -f | base64 -w0");
-
-    // Sandcastle machines don't have arc setup. We copy the user certificate
-    // and authenticate using that in sandcastle
-    $setup = array(
-      "name" => "Setup arcrc",
-      "shell" => "echo " . $arcrc_content . " | base64 --decode"
-                 . " | gzip -d > ~/.arcrc",
-      "user" => "root"
-    );
-
-    // arc demands certain permission on its config
-    $fix_permission = array(
-      "name" => "Fix environment",
-      "shell" => "chmod 600 ~/.arcrc",
-      "user" => "root"
-    );
-
-    // fbcode is a sub-repo. We cannot patch until we add it to ignore otherwise
-    // git thinks it is uncommited change
-    $fix_git_ignore = array(
-      "name" => "Fix git ignore",
-      "shell" => "echo fbcode >> .git/info/exclude",
-      "user" => "root"
-    );
-
-    // Patch the code (keep your fingures crossed)
-    $patch = array(
-      "name" => "Patch " . $diffID,
-      "shell" => "HTTPS_PROXY=fwdproxy:8080 arc --arcrc-file ~/.arcrc "
-                  . "patch --nocommit --diff " . $diffID,
-      "user" => "root"
-    );
-
-    // Clean up the user arc config we are using
-    $cleanup = array(
-      "name" => "Arc cleanup",
-      "shell" => "rm -f ~/.arcrc",
-      "user" => "root"
-    );
-
-    // Construct the steps in the order of execution
-    $steps[] = $setup;
-    $steps[] = $fix_permission;
-    $steps[] = $fix_git_ignore;
-    $steps[] = $patch;
-
-    // Run the actual command
-    $this->updateTest($diffID, $test);
-    $cmd = $this->updateTestCommand($diffID, $test, "running") . ";"
-           . "./build_tools/precommit_checker.py " . $test
-           . "; exit_code=$?; ([[ \$exit_code -eq 0 ]] &&"
-           . $this->updateTestCommand($diffID, $test, "pass") . ")"
-           . "||" . $this->updateTestCommand($diffID, $test, "fail")
-           . "; cat /tmp/precommit-check.log"
-           . "; for f in `ls t/log-*`; do echo \$f; cat \$f; done;"
-           . "[[ \$exit_code -eq 0 ]]";
-
-    $run_test = array(
-      "name" => "Run " . $test,
-      "shell" => $cmd,
-      "user" => "root",
-    );
-
-    $steps[] = $run_test;
-    $steps[] = $cleanup;
-
-    return $steps;
-  }
-
-  function startTestsInSandcastle($workflow) {
-    // extract information we need from workflow or CLI
-    $diffID = $workflow->getDiffId();
-    $username = exec("whoami");
-
-    if ($diffID == null || $username == null) {
-      // there is no diff and we can't extract username
-      // we cannot schedule sandcasstle job
-      return;
-    }
-
-    if (strcmp(getenv("ROCKSDB_CHECK_ALL"), 1) == 0) {
-      // extract all tests from the CI definition
-      $output = file_get_contents("build_tools/rocksdb-lego-determinator");
-      preg_match_all('/[ ]{2}([a-zA-Z0-9_]+)[\)]{1}/', $output, $matches);
-      $tests = $matches[1];
-    } else {
-      // manually list of tests we want to run in sandcastle
-      $tests = array(
-        "unit", "unit_481", "clang_unit", "tsan", "asan", "lite_test", "valgrind"
-      );
-    }
-
-    // construct a job definition for each test and add it to the master plan
-    foreach ($tests as $test) {
-      $arg[] = array(
-        "name" => "RocksDB diff " . $diffID . " test " . $test,
-        "steps" => $this->getSteps($diffID, $username, $test)
-      );
-    }
-
-    // we cannot submit the parallel execution master plan to sandcastle
-    // we need supply the job plan as a determinator
-    // so we construct a small job that will spit out the master job plan
-    // which sandcastle will parse and execute
-    // Why compress ? Otherwise we run over the max string size.
-    $cmd = "echo " . base64_encode(json_encode($arg))
-           . " | gzip -f | base64 -w0";
-    $arg_encoded = shell_exec($cmd);
-
-    $command = array(
-      "name" => "Run diff " . $diffID . "for user " . $username,
-      "steps" => array()
-    );
-
-    $command["steps"][] = array(
-      "name" => "Generate determinator",
-      "shell" => "echo " . $arg_encoded . " | base64 --decode | gzip -d"
-                 . " | base64 --decode",
-      "determinator" => true,
-      "user" => "root"
-    );
-
-    // submit to sandcastle
-    $url = 'https://interngraph.intern.facebook.com/sandcastle/generate?'
-            .'command=SandcastleUniversalCommand'
-            .'&vcs=rocksdb-git&revision=origin%2Fmaster&type=lego'
-            .'&user=krad&alias=rocksdb-precommit'
-            .'&command-args=' . urlencode(json_encode($command));
-
-    if (file_exists('/home/krad/.sandcastle')) {
-      $cmd = 'cat /home/krad/.sandcastle';
-    } else {
-      $cmd = 'cat ~/.sandcastle';
-    }
-    $sandcastle_config = explode(':', rtrim(shell_exec($cmd)));
-
-    if (count($sandcastle_config) != 2) {
-      print('.sandcastle does not contain valid configuration');
-      return;
-    }
-
-    $app = $sandcastle_config[0];
-    $token = $sandcastle_config[1];
-
-    $cmd = 'https_proxy= HTTPS_PROXY= curl -s -k -F app=' . $app . ' '
-            . '-F token=' . $token . ' "' . $url . '"';
-
-    $output = shell_exec($cmd);
-
-    // extract sandcastle URL from the response
-    preg_match('/url": "(.+)"/', $output, $sandcastle_url);
-
-    if (count($sandcastle_url) > 1) {
-      echo "\nSandcastle URL: " . $sandcastle_url[1] . "\n";
-
-      // Ask phabricator to display it on the diff UI
-      $this->postURL($diffID, $sandcastle_url[1]);
-    } else {
-      print("Error submitting job to sandcastle.");
-      print($output);
+      // When submitting a diff this code path gets executed multiple times in
+      // a row. We only care about the case when ID for the diff is provided
+      // because that's what we need to apply the diff and trigger the tests.
+      if (strlen($diffID) > 0) {
+        assert(is_numeric($diffID));
+        startTestsInSandcastle(true /* $applyDiff */, $workflow, $diffID);
+      }
     }
   }
 }
diff --git a/arcanist_util/config/FacebookOldArcanistConfiguration.php b/arcanist_util/config/FacebookOldArcanistConfiguration.php
index 4e936ce7e..aaab040dd 100644
--- a/arcanist_util/config/FacebookOldArcanistConfiguration.php
+++ b/arcanist_util/config/FacebookOldArcanistConfiguration.php
@@ -4,184 +4,33 @@
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
 
+require('RocksDBCommonHelper.php');
+
+define("DIFF_COMMAND", "diff");
+
 class FacebookArcanistConfiguration extends ArcanistConfiguration {
 
   public function didRunWorkflow($command,
                                  ArcanistBaseWorkflow $workflow,
                                  $error_code) {
-    if ($command == 'diff' && !$workflow->isRawDiffSource()) {
-      $this->startTestsInSandcastle($workflow);
+    // Default options don't terminate on failure, but that's what we want. In
+    // the current case we use assertions intentionally as "terminate on failure
+    // invariants".
+    assert_options(ASSERT_BAIL, true);
+
+    assert($workflow);
+    assert(strlen($command) > 0);
+
+    if ($command == DIFF_COMMAND && !$workflow->isRawDiffSource()) {
+      $diffID = $workflow->getDiffId();
+
+      // When submitting a diff this code path gets executed multiple times in
+      // a row. We only care about the case when ID for the diff is provided
+      // because that's what we need to apply the diff and trigger the tests.
+      if (strlen($diffID) > 0) {
+        assert(is_numeric($diffID));
+        startTestsInSandcastle(true /* $applyDiff */, $workflow, $diffID);
+      }
     }
   }
-
-  //////////////////////////////////////////////////////////////////////
-  /*  Run tests in sandcastle */
-  function postURL($diffID, $url) {
-    $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
-           . '"name":"click here for sandcastle tests for D' . $diffID . '", '
-           . '"link":"' . $url . '"}\' | '
-           . 'http_proxy=fwdproxy.any.facebook.com:8080 '
-           . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
-           . 'differential.updateunitresults';
-    shell_exec($cmd);
-  }
-
-  function updateTestCommand($diffID, $test, $status) {
-    $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
-           . '"name":"' . $test . '", '
-           . '"result":"' . $status . '"}\' | '
-           . 'http_proxy=fwdproxy.any.facebook.com:8080 '
-           . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
-           . 'differential.updateunitresults';
-    return $cmd;
-  }
-
-  function updateTest($diffID, $test) {
-    shell_exec($this->updateTestCommand($diffID, $test, "waiting"));
-  }
-
-  function getSteps($diffID, $username, $test) {
-    $arcrc_content = exec("cat ~/.arcrc | gzip -f | base64 -w0");
-
-    // Sandcastle machines don't have arc setup. We copy the user certificate
-    // and authenticate using that in sandcastle
-    $setup = array(
-      "name" => "Setup arcrc",
-      "shell" => "echo " . $arcrc_content . " | base64 --decode"
-                 . " | gzip -d > ~/.arcrc",
-      "user" => "root"
-    );
-
-    // arc demands certain permission on its config
-    $fix_permission = array(
-      "name" => "Fix environment",
-      "shell" => "chmod 600 ~/.arcrc",
-      "user" => "root"
-    );
-
-    // fbcode is a sub-repo. We cannot patch until we add it to ignore otherwise
-    // git thinks it is uncommited change
-    $fix_git_ignore = array(
-      "name" => "Fix git ignore",
-      "shell" => "echo fbcode >> .git/info/exclude",
-      "user" => "root"
-    );
-
-    // Patch the code (keep your fingures crossed)
-    $patch = array(
-      "name" => "Patch " . $diffID,
-      "shell" => "HTTPS_PROXY=fwdproxy:8080 arc --arcrc-file ~/.arcrc "
-                  . "patch --nocommit --diff " . $diffID,
-      "user" => "root"
-    );
-
-    // Clean up the user arc config we are using
-    $cleanup = array(
-      "name" => "Arc cleanup",
-      "shell" => "rm -f ~/.arcrc",
-      "user" => "root"
-    );
-
-    // Construct the steps in the order of execution
-    $steps[] = $setup;
-    $steps[] = $fix_permission;
-    $steps[] = $fix_git_ignore;
-    $steps[] = $patch;
-
-    // Run the actual command
-    $this->updateTest($diffID, $test);
-    $cmd = $this->updateTestCommand($diffID, $test, "running") . ";"
-           . "./build_tools/precommit_checker.py " . $test
-           . "; exit_code=$?; ([[ \$exit_code -eq 0 ]] &&"
-           . $this->updateTestCommand($diffID, $test, "pass") . ")"
-           . "||" . $this->updateTestCommand($diffID, $test, "fail")
-           . "; cat /tmp/precommit-check.log"
-           . "; for f in `ls t/log-*`; do echo \$f; cat \$f; done;"
-           . "[[ \$exit_code -eq 0 ]]";
-
-    $run_test = array(
-      "name" => "Run " . $test,
-      "shell" => $cmd,
-      "user" => "root",
-    );
-
-    $steps[] = $run_test;
-    $steps[] = $cleanup;
-
-    return $steps;
-  }
-
-  function startTestsInSandcastle($workflow) {
-    // extract information we need from workflow or CLI
-    $diffID = $workflow->getDiffId();
-    $username = exec("whoami");
-
-    if ($diffID == null || $username == null) {
-      // there is no diff and we can't extract username
-      // we cannot schedule sandcasstle job
-      return;
-    }
-
-    if (strcmp(getenv("ROCKSDB_CHECK_ALL"), 1) == 0) {
-      // extract all tests from the CI definition
-      $output = file_get_contents("build_tools/rocksdb-lego-determinator");
-      preg_match_all('/[ ]{2}([a-zA-Z0-9_]+)[\)]{1}/', $output, $matches);
-      $tests = $matches[1];
-    } else {
-      // manually list of tests we want to run in sandcastle
-      $tests = array(
-        "unit", "unit_481", "clang_unit", "tsan", "asan", "lite_test", "valgrind"
-      );
-    }
-
-    // construct a job definition for each test and add it to the master plan
-    foreach ($tests as $test) {
-      $arg[] = array(
-        "name" => "RocksDB diff " . $diffID . " test " . $test,
-        "steps" => $this->getSteps($diffID, $username, $test)
-      );
-    }
-
-    // we cannot submit the parallel execution master plan to sandcastle
-    // we need supply the job plan as a determinator
-    // so we construct a small job that will spit out the master job plan
-    // which sandcastle will parse and execute
-    // Why compress ? Otherwise we run over the max string size.
-    $cmd = "echo " . base64_encode(json_encode($arg))
-           . " | gzip -f | base64 -w0";
-    $arg_encoded = shell_exec($cmd);
-
-    $command = array(
-      "name" => "Run diff " . $diffID . "for user " . $username,
-      "steps" => array()
-    );
-
-    $command["steps"][] = array(
-      "name" => "Generate determinator",
-      "shell" => "echo " . $arg_encoded . " | base64 --decode | gzip -d"
-                 . " | base64 --decode",
-      "determinator" => true,
-      "user" => "root"
-    );
-
-    // submit to sandcastle
-    $url = 'https://interngraph.intern.facebook.com/sandcastle/generate?'
-            .'command=SandcastleUniversalCommand'
-            .'&vcs=rocksdb-git&revision=origin%2Fmaster&type=lego'
-            .'&user=krad&alias=rocksdb-precommit'
-            .'&command-args=' . urlencode(json_encode($command));
-
-    $cmd = 'https_proxy= HTTPS_PROXY= curl -s -k -F app=659387027470559 '
-            . '-F token=AeO_3f2Ya3TujjnxGD4 "' . $url . '"';
-
-    $output = shell_exec($cmd);
-
-    // extract sandcastle URL from the response
-    preg_match('/url": "(.+)"/', $output, $sandcastle_url);
-
-    echo "\nSandcastle URL: " . $sandcastle_url[1] . "\n";
-
-    // Ask phabricator to display it on the diff UI
-    $this->postURL($diffID, $sandcastle_url[1]);
-  }
 }
diff --git a/arcanist_util/config/RocksDBCommonHelper.php b/arcanist_util/config/RocksDBCommonHelper.php
new file mode 100644
index 000000000..072f3f64f
--- /dev/null
+++ b/arcanist_util/config/RocksDBCommonHelper.php
@@ -0,0 +1,326 @@
+<?php
+// Copyright 2004-present Facebook. All Rights Reserved.
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree. An additional grant
+// of patent rights can be found in the PATENTS file in the same directory.
+
+// Name of the environment variables which need to be set by the entity which
+// triggers continuous runs so that code at the end of the file gets executed
+// and Sandcastle run starts.
+define("ENV_POST_RECEIVE_HOOK", "POST_RECEIVE_HOOK");
+define("ENV_HTTPS_APP_VALUE", "HTTPS_APP_VALUE");
+define("ENV_HTTPS_TOKEN_VALUE", "HTTPS_TOKEN_VALUE");
+
+define("PRIMARY_TOKEN_FILE", '/home/krad/.sandcastle');
+define("SECONDARY_TOKEN_FILE", '$HOME/.sandcastle');
+define("CONT_RUN_ALIAS", "leveldb");
+
+//////////////////////////////////////////////////////////////////////
+/*  Run tests in sandcastle */
+function postURL($diffID, $url) {
+  assert(strlen($diffID) > 0);
+  assert(is_numeric($diffID));
+  assert(strlen($url) > 0);
+
+  $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
+         . '"name":"click here for sandcastle tests for D' . $diffID . '", '
+         . '"link":"' . $url . '"}\' | '
+         . 'http_proxy=fwdproxy.any.facebook.com:8080 '
+         . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
+         . 'differential.updateunitresults';
+  shell_exec($cmd);
+}
+
+function buildUpdateTestStatusCmd($diffID, $test, $status) {
+  assert(strlen($diffID) > 0);
+  assert(is_numeric($diffID));
+  assert(strlen($test) > 0);
+  assert(strlen($status) > 0);
+
+  $cmd = 'echo \'{"diff_id": "' . $diffID . '", '
+         . '"name":"' . $test . '", '
+         . '"result":"' . $status . '"}\' | '
+         . 'http_proxy=fwdproxy.any.facebook.com:8080 '
+         . 'https_proxy=fwdproxy.any.facebook.com:8080 arc call-conduit '
+         . 'differential.updateunitresults';
+  return $cmd;
+}
+
+function updateTestStatus($diffID, $test) {
+  assert(strlen($diffID) > 0);
+  assert(is_numeric($diffID));
+  assert(strlen($test) > 0);
+
+  shell_exec(buildUpdateTestStatusCmd($diffID, $test, "waiting"));
+}
+
+function getSteps($applyDiff, $diffID, $username, $test) {
+  assert(strlen($username) > 0);
+  assert(strlen($test) > 0);
+
+  if ($applyDiff) {
+    assert(strlen($diffID) > 0);
+    assert(is_numeric($diffID));
+
+    $arcrc_content = exec("cat ~/.arcrc | gzip -f | base64 -w0");
+    assert(strlen($arcrc_content) > 0);
+
+    // Sandcastle machines don't have arc setup. We copy the user certificate
+    // and authenticate using that in Sandcastle.
+    $setup = array(
+      "name" => "Setup arcrc",
+      "shell" => "echo " . $arcrc_content . " | base64 --decode"
+                 . " | gzip -d > ~/.arcrc",
+      "user" => "root"
+    );
+
+    // arc demands certain permission on its config.
+    $fix_permission = array(
+      "name" => "Fix environment",
+      "shell" => "chmod 600 ~/.arcrc",
+      "user" => "root"
+    );
+
+    // Construct the steps in the order of execution.
+    $steps[] = $setup;
+    $steps[] = $fix_permission;
+  }
+
+  // fbcode is a sub-repo. We cannot patch until we add it to ignore otherwise
+  // Git thinks it is an uncommited change.
+  $fix_git_ignore = array(
+    "name" => "Fix git ignore",
+    "shell" => "echo fbcode >> .git/info/exclude",
+    "user" => "root"
+  );
+
+  $steps[] = $fix_git_ignore;
+
+  // This will be the command used to execute particular type of tests.
+  $cmd = "";
+
+  if ($applyDiff) {
+    // Patch the code (keep your fingures crossed).
+    $patch = array(
+      "name" => "Patch " . $diffID,
+      "shell" => "HTTPS_PROXY=fwdproxy:8080 arc --arcrc-file ~/.arcrc "
+                  . "patch --nocommit --diff " . $diffID,
+      "user" => "root"
+    );
+
+    $steps[] = $patch;
+
+    updateTestStatus($diffID, $test);
+    $cmd = buildUpdateTestStatusCmd($diffID, $test, "running") . "; ";
+  }
+
+  // Run the actual command.
+  $cmd = $cmd . "./build_tools/precommit_checker.py " . $test
+           . "; exit_code=$?; ";
+
+  if ($applyDiff) {
+    $cmd = $cmd . "([[ \$exit_code -eq 0 ]] &&"
+                . buildUpdateTestStatusCmd($diffID, $test, "pass") . ")"
+                . "||" . buildUpdateTestStatusCmd($diffID, $test, "fail")
+                . "; ";
+  }
+
+  $cmd = $cmd . " cat /tmp/precommit-check.log"
+           . "; for f in `ls t/log-*`; do echo \$f; cat \$f; done;"
+           . "[[ \$exit_code -eq 0 ]]";
+  assert(strlen($cmd) > 0);
+
+  $run_test = array(
+    "name" => "Run " . $test,
+    "shell" => $cmd,
+    "user" => "root",
+  );
+
+  $steps[] = $run_test;
+
+  if ($applyDiff) {
+    // Clean up the user arc config we are using.
+    $cleanup = array(
+      "name" => "Arc cleanup",
+      "shell" => "rm -f ~/.arcrc",
+      "user" => "root"
+    );
+
+    $steps[] = $cleanup;
+  }
+
+  assert(count($steps) > 0);
+  return $steps;
+}
+
+function getSandcastleConfig() {
+  $sandcastle_config = array();
+
+  // This is a case when we're executed from a continuous run. Fetch the values
+  // from the environment.
+  if (getenv(ENV_POST_RECEIVE_HOOK)) {
+    $sandcastle_config[0] = getenv(ENV_HTTPS_APP_VALUE);
+    $sandcastle_config[1] = getenv(ENV_HTTPS_TOKEN_VALUE);
+  } else {
+    // This is a typical `[p]arc diff` case. Fetch the values from the specific
+    // configuration files.
+    assert(file_exists(PRIMARY_TOKEN_FILE) ||
+           file_exists(SECONDARY_TOKEN_FILE));
+
+    // Try the primary location first, followed by a secondary.
+    if (file_exists(PRIMARY_TOKEN_FILE)) {
+      $cmd = 'cat ' . PRIMARY_TOKEN_FILE;
+    } else {
+      $cmd = 'cat ' . SECONDARY_TOKEN_FILE;
+    }
+
+    assert(strlen($cmd) > 0);
+    $sandcastle_config = explode(':', rtrim(shell_exec($cmd)));
+  }
+
+  // In this case be very explicit about the implications.
+  if (count($sandcastle_config) != 2) {
+    echo "Sandcastle configuration files don't contain valid information " .
+         "or the necessary environment variables aren't defined. Unable " .
+         "to validate the code changes.";
+    exit(1);
+  }
+
+  assert(strlen($sandcastle_config[0]) > 0);
+  assert(strlen($sandcastle_config[1]) > 0);
+  assert(count($sandcastle_config) > 0);
+
+  return $sandcastle_config;
+}
+
+// This function can be called either from `[p]arc diff` command or during
+// the Git post-receive hook.
+ function startTestsInSandcastle($applyDiff, $workflow, $diffID) {
+  // Default options don't terminate on failure, but that's what we want. In
+  // the current case we use assertions intentionally as "terminate on failure
+  // invariants".
+  assert_options(ASSERT_BAIL, true);
+
+  // In case of a diff we'll send notificatios to the author. Else it'll go to
+  // the entire team because failures indicate that build quality has regressed.
+  $username = $applyDiff ? exec("whoami") : CONT_RUN_ALIAS;
+  assert(strlen($username) > 0);
+
+  if ($applyDiff) {
+    assert($workflow);
+    assert(strlen($diffID) > 0);
+    assert(is_numeric($diffID));
+  }
+
+  if (strcmp(getenv("ROCKSDB_CHECK_ALL"), 1) == 0) {
+    // Extract all tests from the CI definition.
+    $output = file_get_contents("build_tools/rocksdb-lego-determinator");
+    assert(strlen($output) > 0);
+
+    preg_match_all('/[ ]{2}([a-zA-Z0-9_]+)[\)]{1}/', $output, $matches);
+    $tests = $matches[1];
+    assert(count($tests) > 0);
+  } else {
+    // Manually list of tests we want to run in Sandcastle.
+    $tests = array(
+      "unit", "unit_481", "clang_unit", "tsan", "asan", "lite_test",
+      "valgrind"
+    );
+  }
+
+  $send_email_template = array(
+    'type' => 'email',
+    'triggers' => array('fail'),
+    'emails' => array($username . '@fb.com'),
+  );
+
+  // Construct a job definition for each test and add it to the master plan.
+  foreach ($tests as $test) {
+    $stepName = "RocksDB diff " . $diffID . " test " . $test;
+
+    if (!$applyDiff) {
+      $stepName = "RocksDB continuous integration test " . $test;
+    }
+
+    $arg[] = array(
+      "name" => $stepName,
+      "report" => array($send_email_template),
+      "steps" => getSteps($applyDiff, $diffID, $username, $test)
+    );
+  }
+
+  // We cannot submit the parallel execution master plan to Sandcastle and
+  // need supply the job plan as a determinator. So we construct a small job
+  // that will spit out the master job plan which Sandcastle will parse and
+  // execute. Why compress the job definitions? Otherwise we run over the max
+  // string size.
+  $cmd = "echo " . base64_encode(json_encode($arg))
+         . " | gzip -f | base64 -w0";
+  assert(strlen($cmd) > 0);
+
+  $arg_encoded = shell_exec($cmd);
+  assert(strlen($arg_encoded) > 0);
+
+  $runName = "Run diff " . $diffID . "for user " . $username;
+
+  if (!$applyDiff) {
+    $runName = "RocksDB continuous integration build and test run";
+  }
+
+  $command = array(
+    "name" => $runName,
+    "steps" => array()
+  );
+
+  $command["steps"][] = array(
+    "name" => "Generate determinator",
+    "shell" => "echo " . $arg_encoded . " | base64 --decode | gzip -d"
+               . " | base64 --decode",
+    "determinator" => true,
+    "user" => "root"
+  );
+
+  // Submit to Sandcastle.
+  $url = 'https://interngraph.intern.facebook.com/sandcastle/generate?'
+          .'command=SandcastleUniversalCommand'
+          .'&vcs=rocksdb-git&revision=origin%2Fmaster&type=lego'
+          .'&user=' . $username . '&alias=rocksdb-precommit'
+          .'&command-args=' . urlencode(json_encode($command));
+
+  // Fetch the configuration necessary to submit a successful HTTPS request.
+  $sandcastle_config = getSandcastleConfig();
+
+  $app = $sandcastle_config[0];
+  $token = $sandcastle_config[1];
+
+  $cmd = 'https_proxy= HTTPS_PROXY= curl -s -k -F app=' . $app . ' '
+          . '-F token=' . $token . ' "' . $url . '"';
+
+  $output = shell_exec($cmd);
+  assert(strlen($output) > 0);
+
+  // Extract Sandcastle URL from the response.
+  preg_match('/url": "(.+)"/', $output, $sandcastle_url);
+
+  assert(count($sandcastle_url) > 0, "Unable to submit Sandcastle request.");
+  assert(strlen($sandcastle_url[1]) > 0, "Unable to extract Sandcastle URL.");
+
+  if ($applyDiff) {
+    echo "\nSandcastle URL: " . $sandcastle_url[1] . "\n";
+    // Ask Phabricator to display it on the diff UI.
+    postURL($diffID, $sandcastle_url[1]);
+  } else {
+    echo "Continuous integration started Sandcastle tests. You can look at ";
+    echo "the progress at:\n" . $sandcastle_url[1] . "\n";
+  }
+}
+
+// Continuous run cript will set the environment variable and based on that
+// we'll trigger the execution of tests in Sandcastle. In that case we don't
+// need to apply any diffs and there's no associated workflow either.
+if (getenv(ENV_POST_RECEIVE_HOOK)) {
+  startTestsInSandcastle(
+    false /* $applyDiff */,
+    NULL /* $workflow */,
+    NULL /* $diffID */);
+}
diff --git a/build_tools/cont_integration.sh b/build_tools/cont_integration.sh
new file mode 100755
index 000000000..390f30c7e
--- /dev/null
+++ b/build_tools/cont_integration.sh
@@ -0,0 +1,87 @@
+#!/bin/bash
+#
+# Copyright (c) 2016, Facebook. All rights reserved.
+#
+# Overall wrapper script for RocksDB continuous builds. The implementation is a
+# trivial pulling scheme. We loop infinitely, check if any new changes have been
+# committed, if yes then trigger a Sandcastle run, and finally go to sleep again
+# for a certain interval.
+#
+
+function log {
+  DATE=`date +%Y-%m-%d:%H:%M:%S`
+  echo $DATE $@
+}
+
+function log_err {
+  log "ERROR: $@. Error code: $?."
+}
+
+#
+# Execution starts here.
+#
+
+# Path to the determinator from the root of the RocksDB repo.
+CONTRUN_DETERMINATOR=./arcanist_util/config/RocksDBCommonDeterminator.php
+
+# Value of the previous commit.
+PREV_COMMIT=
+
+log "Starting to monitor for new RocksDB changes ..."
+log "Running under `pwd` as `whoami`."
+
+# Paranoia. Make sure that we're using the right branch.
+git checkout master
+
+if [ ! $? -eq 0 ]; then
+  log_err "This is not good. Can't checkout master. Bye-bye!"
+  exit 1
+fi
+
+# We'll run forever and let the execution environment terminate us if we'll
+# exceed whatever timeout is set for the job.
+while true;
+do
+  # Get the latest changes committed.
+  git pull --rebase
+
+  if [  $? -eq 0 ]; then
+    LAST_COMMIT=`git log -1 | head -1 | grep commit | awk '{ print $2; }'`
+
+    log "Last commit is '$LAST_COMMIT', previous commit is '$PREV_COMMIT'."
+
+    if [ "$PREV_COMMIT" == "$LAST_COMMIT" ]; then
+      log "There were no changes since the last time I checked. Going to sleep."
+    else
+      if [ ! -z "$LAST_COMMIT" ]; then
+        log "New code has been committed or previous commit not know. " \
+            "Will trigger the tests."
+
+        PREV_COMMIT=$LAST_COMMIT
+        log "Updated previous commit to '$PREV_COMMIT'."
+
+        #
+        # This is where we'll trigger the Sandcastle run. The values for
+        # HTTPS_APP_VALUE and HTTPS_APP_VALUE will be set in the container we're
+        # running in.
+        #
+        POST_RECEIVE_HOOK=1 php $CONTRUN_DETERMINATOR
+
+        if [ $? -eq 0 ]; then
+          log "Sandcastle run successfully triggered."
+        else
+          log_err "Failed to trigger Sandcastle run."
+        fi
+      else
+        log_err "Previous commit not updated. Don't know what the last one is."
+      fi
+    fi
+  else
+    log_err "git pull --rebase failed. Will skip running tests for now."
+  fi
+
+  # Always sleep, even if errors happens while trying to determine the latest
+  # commit. This will prevent us terminating in case of transient errors.
+  log "Will go to sleep for 5 minutes."
+  sleep 5m
+done