From f14037e54577ce79cec00e06735f914c01b3f80e Mon Sep 17 00:00:00 2001
From: Hugh Han <hughhan1@gmail.com>
Date: Wed, 26 Jul 2017 13:28:57 -0400
Subject: SERVER-30324 Move cluster_remove_shard_cmd to mongod

---
 .../db/s/config/configsvr_remove_shard_command.cpp | 106 ++++++++++++++++++++-
 1 file changed, 105 insertions(+), 1 deletion(-)

(limited to 'src/mongo/db')

diff --git a/src/mongo/db/s/config/configsvr_remove_shard_command.cpp b/src/mongo/db/s/config/configsvr_remove_shard_command.cpp
index 5ac9d2dc224..d24516b0a9c 100644
--- a/src/mongo/db/s/config/configsvr_remove_shard_command.cpp
+++ b/src/mongo/db/s/config/configsvr_remove_shard_command.cpp
@@ -42,6 +42,7 @@
 #include "mongo/s/catalog/sharding_catalog_manager.h"
 #include "mongo/s/catalog/type_database.h"
 #include "mongo/s/catalog_cache.h"
+#include "mongo/s/client/shard_registry.h"
 #include "mongo/s/grid.h"
 #include "mongo/util/log.h"
 #include "mongo/util/scopeguard.h"
@@ -65,7 +66,7 @@ public:
     }
 
     virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
-        return false;
+        return true;
     }
 
     virtual void help(std::stringstream& help) const override {
@@ -73,11 +74,114 @@ public:
                 "directly. Removes a shard from the cluster.";
     }
 
+    Status checkAuthForCommand(Client* client,
+                               const std::string& dbname,
+                               const BSONObj& cmdObj) override {
+        if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
+                ResourcePattern::forClusterResource(), ActionType::internal)) {
+            return Status(ErrorCodes::Unauthorized, "Unauthorized");
+        }
+        return Status::OK();
+    }
+
     bool run(OperationContext* opCtx,
              const std::string& dbname,
              const BSONObj& cmdObj,
              BSONObjBuilder& result) {
 
+        uassert(ErrorCodes::IllegalOperation,
+                "_configsvrRemoveShard can only be run on config servers",
+                serverGlobalParams.clusterRole == ClusterRole::ConfigServer);
+
+        uassert(ErrorCodes::TypeMismatch,
+                str::stream() << "Field '" << cmdObj.firstElement().fieldName()
+                              << "' must be of type string",
+                cmdObj.firstElement().type() == BSONType::String);
+        const std::string target = cmdObj.firstElement().str();
+
+        const auto shardStatus = grid.shardRegistry()->getShard(opCtx, ShardId(target));
+        if (!shardStatus.isOK()) {
+            std::string msg(str::stream() << "Could not drop shard '" << target
+                                          << "' because it does not exist");
+            log() << msg;
+            return appendCommandStatus(result, Status(ErrorCodes::ShardNotFound, msg));
+        }
+        const auto shard = shardStatus.getValue();
+
+        const auto shardingCatalogManager = ShardingCatalogManager::get(opCtx);
+
+        StatusWith<ShardDrainingStatus> removeShardResult =
+            shardingCatalogManager->removeShard(opCtx, shard->getId());
+        if (!removeShardResult.isOK()) {
+            return appendCommandStatus(result, removeShardResult.getStatus());
+        }
+
+        std::vector<std::string> databases;
+        Status status =
+            shardingCatalogManager->getDatabasesForShard(opCtx, shard->getId(), &databases);
+        if (!status.isOK()) {
+            return appendCommandStatus(result, status);
+        }
+
+        // Get BSONObj containing:
+        // 1) note about moving or dropping databases in a shard
+        // 2) list of databases (excluding 'local' database) that need to be moved
+        BSONObj dbInfo;
+        {
+            BSONObjBuilder dbInfoBuilder;
+            dbInfoBuilder.append("note", "you need to drop or movePrimary these databases");
+            BSONArrayBuilder dbs(dbInfoBuilder.subarrayStart("dbsToMove"));
+            for (std::vector<std::string>::const_iterator it = databases.begin();
+                 it != databases.end();
+                 it++) {
+                if (*it != "local") {
+                    dbs.append(*it);
+                }
+            }
+            dbs.doneFast();
+            dbInfo = dbInfoBuilder.obj();
+        }
+
+        // TODO: Standardize/Seperate how we append to the result object
+        switch (removeShardResult.getValue()) {
+            case ShardDrainingStatus::STARTED:
+                result.append("msg", "draining started successfully");
+                result.append("state", "started");
+                result.append("shard", shard->getId().toString());
+                result.appendElements(dbInfo);
+                break;
+            case ShardDrainingStatus::ONGOING: {
+                std::vector<ChunkType> chunks;
+                Status status = Grid::get(opCtx)->catalogClient()->getChunks(
+                    opCtx,
+                    BSON(ChunkType::shard(shard->getId().toString())),
+                    BSONObj(),
+                    boost::none,  // return all
+                    &chunks,
+                    nullptr,
+                    repl::ReadConcernLevel::kMajorityReadConcern);
+                if (!status.isOK()) {
+                    return appendCommandStatus(result, status);
+                }
+
+                result.append("msg", "draining ongoing");
+                result.append("state", "ongoing");
+                {
+                    BSONObjBuilder inner;
+                    inner.append("chunks", static_cast<long long>(chunks.size()));
+                    inner.append("dbs", static_cast<long long>(databases.size()));
+                    BSONObj b = inner.obj();
+                    result.append("remaining", b);
+                }
+                result.appendElements(dbInfo);
+                break;
+            }
+            case ShardDrainingStatus::COMPLETED:
+                result.append("msg", "removeshard completed successfully");
+                result.append("state", "completed");
+                result.append("shard", shard->getId().toString());
+        }
+
         return true;
     }
 
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