mongodb/jstests/noPassthrough/mongos_exhausts_stale_config_retries.js

// Verifies mongos returns StaleConfig if it exhausts its allowed stale version retry attempts,
// using the command read and write modes.
//
// @tags: [requires_sharding]
(function() {
    "use strict";

    const dbName = "test";
    const collName = "foo";
    const ns = dbName + '.' + collName;

    const st = new ShardingTest({shards: 2, config: 1});
    const testDB = st.s.getDB(dbName);

    // Only testing the command read and write modes.
    assert(testDB.getMongo().readMode() === "commands");
    assert(testDB.getMongo().writeMode() === "commands");

    // Shard a collection with the only chunk on shard0.
    assert.commandWorked(st.s.adminCommand({enableSharding: dbName}));
    st.ensurePrimaryShard(dbName, st.shard0.shardName);
    assert.commandWorked(st.s.adminCommand({shardCollection: ns, key: {_id: 1}}));

    const sourcePrimary = st.rs0.getPrimary();
    const recipientPrimary = st.rs1.getPrimary();

    // Disable the best-effort recipient metadata refresh after migrations and move the chunk
    // between shards so the recipient shard, shard1, is stale.
    assert.commandWorked(sourcePrimary.adminCommand(
        {configureFailPoint: "doNotRefreshRecipientAfterCommit", mode: "alwaysOn"}));
    assert.commandWorked(
        st.s.adminCommand({moveChunk: ns, find: {_id: 0}, to: st.shard1.shardName}));

    // Disable metadata refreshes on the recipient shard so it will indefinitely return StaleConfig.
    assert.commandWorked(recipientPrimary.adminCommand(
        {configureFailPoint: "skipShardFilteringMetadataRefresh", mode: "alwaysOn"}));

    // Test various read and write commands that are sent with shard versions and thus can return
    // StaleConfig. Batch writes, i.e. insert/update/delete, return batch responses with ok:1 and
    // NoProgressMade write errors when retries are exhausted, so they are excluded.
    const kCommands = [
        {aggregate: collName, pipeline: [], cursor: {}},
        {count: collName},
        {distinct: collName, query: {}, key: "_id"},
        {find: collName},
        {findAndModify: collName, query: {_id: 0}, update: {$set: {x: 1}}},
    ];

    kCommands.forEach((cmd) => {
        // The recipient shard should return StaleConfig until mongos exhausts its retries and
        // returns the final StaleConfig to the client.
        assert.commandFailedWithCode(testDB.runCommand(cmd),
                                     ErrorCodes.StaleConfig,
                                     "expected to fail with StaleConfig, cmd: " + tojson(cmd));
    });

    assert.commandWorked(sourcePrimary.adminCommand(
        {configureFailPoint: "doNotRefreshRecipientAfterCommit", mode: "off"}));
    assert.commandWorked(recipientPrimary.adminCommand(
        {configureFailPoint: "skipShardFilteringMetadataRefresh", mode: "off"}));

    st.stop();
})();