//
// Tests mongos's failure tolerance for single-node shards
//
// Sets up a cluster with three shards, the first shard of which has an unsharded collection and
// half a sharded collection.  The second shard has the second half of the sharded collection, and
// the third shard has nothing.  Progressively shuts down each shard to see the impact on the
// cluster.
//
// Three different connection states are tested - active (connection is active through whole
// sequence), idle (connection is connected but not used before a shard change), and new
// (connection connected after shard change).
//
(function() {
'use strict';

var st = new ShardingTest({ shards: 3, mongos: 1 });

var admin = st.s0.getDB("admin");

var collSharded = st.s0.getCollection("fooSharded.barSharded");
var collUnsharded = st.s0.getCollection("fooUnsharded.barUnsharded");

assert.commandWorked(admin.runCommand({ enableSharding: collSharded.getDB().toString() }));
st.ensurePrimaryShard(collSharded.getDB().toString(), st.shard0.shardName);

assert.commandWorked(admin.runCommand({ shardCollection: collSharded.toString(),
                                        key: { _id: 1 } }));
assert.commandWorked(admin.runCommand({ split: collSharded.toString(), middle: { _id: 0 } }));
assert.commandWorked(admin.runCommand({ moveChunk: collSharded.toString(),
                                        find: { _id: 0 },
                                        to: st.shard1.shardName }));

// Create the unsharded database
assert.writeOK(collUnsharded.insert({ some: "doc" }));
assert.writeOK(collUnsharded.remove({}));
assert.commandWorked(
    admin.runCommand({ movePrimary: collUnsharded.getDB().toString(), to: st.shard0.shardName }));

//
// Setup is complete
//

jsTest.log("Inserting initial data...");

var mongosConnActive = new Mongo(st.s0.host);
var mongosConnIdle = null;
var mongosConnNew = null;

assert.writeOK(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: -1 }));
assert.writeOK(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: 1 }));
assert.writeOK(mongosConnActive.getCollection(collUnsharded.toString()).insert({ _id: 1 }));

jsTest.log("Stopping third shard...");

mongosConnIdle = new Mongo(st.s0.host);

MongoRunner.stopMongod(st.shard2);

jsTest.log("Testing active connection...");

assert.neq(null, mongosConnActive.getCollection(collSharded.toString()).findOne({ _id: -1 }));
assert.neq(null, mongosConnActive.getCollection(collSharded.toString()).findOne({ _id: 1 }));
assert.neq(null, mongosConnActive.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

assert.writeOK(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: -2 }));
assert.writeOK(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: 2 }));
assert.writeOK(mongosConnActive.getCollection(collUnsharded.toString()).insert({ _id: 2 }));

jsTest.log("Testing idle connection...");

assert.writeOK(mongosConnIdle.getCollection(collSharded.toString()).insert({ _id: -3 }));
assert.writeOK(mongosConnIdle.getCollection(collSharded.toString()).insert({ _id: 3 }));
assert.writeOK(mongosConnIdle.getCollection(collUnsharded.toString()).insert({ _id: 3 }));

assert.neq(null, mongosConnIdle.getCollection(collSharded.toString()).findOne({ _id: -1 }));
assert.neq(null, mongosConnIdle.getCollection(collSharded.toString()).findOne({ _id: 1 }));
assert.neq(null, mongosConnIdle.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

jsTest.log("Testing new connections...");

mongosConnNew = new Mongo(st.s0.host);
assert.neq(null, mongosConnNew.getCollection(collSharded.toString()).findOne({ _id: -1 }));
mongosConnNew = new Mongo(st.s0.host);
assert.neq(null, mongosConnNew.getCollection(collSharded.toString()).findOne({ _id: 1 }));
mongosConnNew = new Mongo(st.s0.host);
assert.neq(null, mongosConnNew.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

mongosConnNew = new Mongo(st.s0.host);
assert.writeOK(mongosConnNew.getCollection(collSharded.toString()).insert({ _id: -4 }));
mongosConnNew = new Mongo(st.s0.host);
assert.writeOK(mongosConnNew.getCollection(collSharded.toString()).insert({ _id: 4 }));
mongosConnNew = new Mongo(st.s0.host);
assert.writeOK(mongosConnNew.getCollection(collUnsharded.toString()).insert({ _id: 4 }));

gc(); // Clean up new connections

jsTest.log("Stopping second shard...");

mongosConnIdle = new Mongo(st.s0.host);

MongoRunner.stopMongod(st.shard1);

jsTest.log("Testing active connection...");

assert.neq(null, mongosConnActive.getCollection(collSharded.toString()).findOne({ _id: -1 }));
assert.neq(null, mongosConnActive.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

assert.writeOK(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: -5 }));

assert.writeError(mongosConnActive.getCollection(collSharded.toString()).insert({ _id: 5 }));
assert.writeOK(mongosConnActive.getCollection(collUnsharded.toString()).insert({ _id: 5 }));

jsTest.log("Testing idle connection...");

assert.writeOK(mongosConnIdle.getCollection(collSharded.toString()).insert({ _id: -6 }));
assert.writeError(mongosConnIdle.getCollection(collSharded.toString()).insert({ _id: 6 }));
assert.writeOK(mongosConnIdle.getCollection(collUnsharded.toString()).insert({ _id: 6 }));

assert.neq(null, mongosConnIdle.getCollection(collSharded.toString()).findOne({ _id: -1 }));
assert.neq(null, mongosConnIdle.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

jsTest.log("Testing new connections...");

mongosConnNew = new Mongo(st.s0.host);
assert.neq(null, mongosConnNew.getCollection(collSharded.toString()).findOne({ _id: -1 }));

mongosConnNew = new Mongo(st.s0.host);
assert.neq(null, mongosConnNew.getCollection(collUnsharded.toString()).findOne({ _id: 1 }));

mongosConnNew = new Mongo(st.s0.host);
assert.writeOK(mongosConnNew.getCollection(collSharded.toString()).insert({ _id: -7 }));

mongosConnNew = new Mongo(st.s0.host);
assert.writeError(mongosConnNew.getCollection(collSharded.toString()).insert({ _id: 7 }));

mongosConnNew = new Mongo(st.s0.host);
assert.writeOK(mongosConnNew.getCollection(collUnsharded.toString()).insert({ _id: 7 }));

st.stop();

})();