SERVER-45094 add replica_sets_reconfig_jscore_passthrough suite

1 files changed, 133 insertions, 0 deletions

diff --git a/jstests/hooks/run_reconfig_background.js b/jstests/hooks/run_reconfig_background.js
new file mode 100644
index 00000000000..2836a8bf68d
--- /dev/null
+++ b/jstests/hooks/run_reconfig_background.js
@@ -0,0 +1,133 @@
+/**
+ * This hook runs two reconfig commands against the primary of a replica set:
+ * (1): The first reconfig command changes the votes and priority of a node to 0, which will
+ * change the voting majority of the set.
+ * (2): The second reconfig command runs against the new voting majority and should succeed.
+ *
+ * This hook will run concurrently with tests.
+ */
+
+'use strict';
+
+(function() {
+load('jstests/libs/discover_topology.js');  // For Topology and DiscoverTopology.
+load('jstests/libs/parallelTester.js');     // For Thread.
+
+if (typeof db === 'undefined') {
+    throw new Error(
+        "Expected mongo shell to be connected a mongod, but global 'db' object isn't defined");
+}
+
+const conn = db.getMongo();
+const topology = DiscoverTopology.findConnectedNodes(conn);
+
+/**
+ * Returns true if the error code is transient.
+ */
+const isIgnorableError = function ignorableError(codeName) {
+    if (codeName == "ConfigurationInProgress" || codeName == "NotMaster") {
+        return true;
+    }
+    return false;
+};
+
+/**
+ * Runs two reconfig commands against the primary of a replica set.
+ *
+ * The first reconfig command randomly chooses a node to change it's votes and priority to 0 or 1
+ * based on what the node's current votes and priority fields are. We always check to see that
+ * there exists at least one voting node in the set, which ensures that we can always have a
+ * primary.
+ * We also want to avoid changing the votes and priority of the current primary to 0 to avoid
+ * unnecessary stepdowns.
+ *
+ * The number of voting nodes in the replica set determines what the config majority is for both
+ * reconfig config commitment and reconfig oplog commitment.
+ *
+ * This function should not throw if everything is working properly.
+ */
+const reconfigBackgroundThread = function reconfigBackground(
+    primary, isIgnorableErrorFunc, numNodes, primaryIndex) {
+    // Calls 'func' with the print() function overridden to be a no-op.
+    Random.setRandomSeed();
+    const quietly = (func) => {
+        const printOriginal = print;
+        try {
+            print = Function.prototype;
+            func();
+        } finally {
+            print = printOriginal;
+        }
+    };
+
+    // Suppress the log messages generated establishing new mongo connections. The
+    // run_reconfig_background.js hook is executed frequently by resmoke.py and
+    // could lead to generating an overwhelming amount of log messages.
+    let conn;
+    quietly(() => {
+        conn = new Mongo(primary);
+    });
+    assert.neq(
+        null, conn, "Failed to connect to primary '" + primary + "' for background reconfigs");
+
+    jsTestLog("Running reconfig to change votes.");
+
+    var config = conn.getDB("local").system.replset.findOne();
+    config.version++;
+
+    // Calculate the total number of voting nodes in this set so that we make sure we
+    // always have at least one voting node.
+    const numVotingNodes = config.members.filter(member => member.votes === 1).length;
+
+    // Randomly change the vote of a node to 1 or 0 depending on its current value. Do not
+    // change the primary's votes.
+    var indexToChange = primaryIndex;
+    while (indexToChange === primaryIndex) {
+        // randInt is exclusive of the upper bound.
+        indexToChange = Random.randInt(numNodes);
+    }
+
+    // Change the priority to correspond to the votes. If the member's current votes field
+    // is 1, only change it to 0 if there is another voting member in this set. Otherwise,
+    // we risk having no voting members (and no suitable primary).
+    config.members[indexToChange].votes = (config.members[indexToChange].votes === 1) ? 0 : 1;
+    config.members[indexToChange].priority = config.members[indexToChange].votes;
+
+    let votingRes = conn.getDB("admin").runCommand({replSetReconfig: config});
+    if (!votingRes.ok && !isIgnorableErrorFunc(votingRes.codeName)) {
+        jsTestLog("Reconfig to change votes FAILED.");
+        return votingRes;
+    }
+
+    jsTestLog("Running reconfig after changing voting majority.");
+
+    config = conn.getDB("local").system.replset.findOne();
+    config.version++;
+    let reconfigRes = conn.getDB("admin").runCommand({replSetReconfig: config});
+    if (!reconfigRes.ok && !isIgnorableErrorFunc(reconfigRes.codeName)) {
+        jsTestLog("Reconfig after changing voting majority FAILED.");
+        return reconfigRes;
+    }
+
+    return {ok: 1};
+};
+
+if (topology.type === Topology.kReplicaSet) {
+    var numNodes = topology.nodes.length;
+    var primaryIndex = topology.nodes.indexOf(topology.primary);
+    const thread = new Thread(
+        reconfigBackgroundThread, topology.primary, isIgnorableError, numNodes, primaryIndex);
+    try {
+        thread.start();
+    } finally {
+        // Wait for thread to finish and throw an error if it fails.
+        let res;
+        thread.join();
+        res = thread.returnData();
+
+        assert.commandWorked(res, () => "reconfig hook failed: " + tojson(res));
+    }
+} else {
+    throw new Error('Unsupported topology configuration: ' + tojson(topology));
+}
+})();