SERVER-43153 Expose pids of spawned processes in the shell

1 files changed, 50 insertions, 0 deletions

diff --git a/jstests/noPassthrough/runningMongoChildProcessIds.js b/jstests/noPassthrough/runningMongoChildProcessIds.js
new file mode 100644
index 00000000000..498e0556020
--- /dev/null
+++ b/jstests/noPassthrough/runningMongoChildProcessIds.js
@@ -0,0 +1,50 @@
+// Tests the _runningMongoChildProcessIds shell built-in.
+
+(function() {
+'use strict';
+
+/**
+ * @param {NumberLong[]} expected pids
+ */
+function assertRunningMongoChildProcessIds(expected) {
+    const expectedSorted = expected.sort();
+    const children = MongoRunner.runningChildPids().sort();
+    assert.eq(expectedSorted, children);
+}
+
+// Empty before we start anything.
+assertRunningMongoChildProcessIds([]);
+
+(function() {
+// Start 1 mongod.
+const mongod = MongoRunner.runMongod({});
+try {
+    // Call 3 times just for good-measure.
+    assertRunningMongoChildProcessIds([mongod.pid]);
+    assertRunningMongoChildProcessIds([mongod.pid]);
+    assertRunningMongoChildProcessIds([mongod.pid]);
+} finally {
+    MongoRunner.stopMongod(mongod);
+}
+})();
+
+(function() {
+// Start 2 mongods.
+const mongod1 = MongoRunner.runMongod({});
+const mongod2 = MongoRunner.runMongod({});
+try {
+    assertRunningMongoChildProcessIds([mongod1.pid, mongod2.pid]);
+
+    // Stop mongod1 and only mongod2 should remain.
+    MongoRunner.stopMongod(mongod1);
+    assertRunningMongoChildProcessIds([mongod2.pid]);
+} finally {
+    // It is safe to stop multiple times.
+    MongoRunner.stopMongos(mongod2);
+    MongoRunner.stopMongos(mongod1);
+}
+})();
+
+// empty at the end
+assertRunningMongoChildProcessIds([]);
+})();