SERVER-49681 Move persistent task store under db

1 files changed, 174 insertions, 0 deletions

diff --git a/src/mongo/db/persistent_task_store.h b/src/mongo/db/persistent_task_store.h
new file mode 100644
index 00000000000..4b0b25af5f6
--- /dev/null
+++ b/src/mongo/db/persistent_task_store.h
@@ -0,0 +1,174 @@
+/**
+ *    Copyright (C) 2019-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/db/dbdirectclient.h"
+#include "mongo/db/namespace_string.h"
+#include "mongo/db/operation_context.h"
+#include "mongo/db/ops/write_ops_gen.h"
+#include "mongo/db/repl/repl_client_info.h"
+#include "mongo/db/write_concern.h"
+#include "mongo/rpc/get_status_from_command_result.h"
+
+namespace mongo {
+
+namespace WriteConcerns {
+
+const WriteConcernOptions kMajorityWriteConcern{WriteConcernOptions::kMajority,
+                                                WriteConcernOptions::SyncMode::UNSET,
+                                                WriteConcernOptions::kWriteConcernTimeoutSharding};
+
+}
+
+template <typename T>
+class PersistentTaskStore {
+public:
+    PersistentTaskStore(NamespaceString storageNss) : _storageNss(std::move(storageNss)) {}
+
+    /**
+     * Adds a task to the store.
+     */
+    void add(OperationContext* opCtx,
+             const T& task,
+             const WriteConcernOptions& writeConcern = WriteConcerns::kMajorityWriteConcern) {
+        DBDirectClient dbClient(opCtx);
+
+        const auto commandResponse = dbClient.runCommand([&] {
+            write_ops::Insert insertOp(_storageNss);
+            insertOp.setDocuments({task.toBSON()});
+            return insertOp.serialize({});
+        }());
+
+        const auto commandReply = commandResponse->getCommandReply();
+        uassertStatusOK(getStatusFromWriteCommandReply(commandReply));
+
+        WriteConcernResult ignoreResult;
+        auto latestOpTime = repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
+        uassertStatusOK(waitForWriteConcern(opCtx, latestOpTime, writeConcern, &ignoreResult));
+    }
+
+    /**
+     * Updates a document that matches the given query using the update modifier specified. Even if
+     * multiple documents match, at most one document will be updated.
+     */
+    void update(OperationContext* opCtx,
+                Query query,
+                const BSONObj& update,
+                const WriteConcernOptions& writeConcern = WriteConcerns::kMajorityWriteConcern,
+                bool upsert = false) {
+        DBDirectClient dbClient(opCtx);
+
+        auto commandResponse = dbClient.runCommand([&] {
+            write_ops::Update updateOp(_storageNss);
+            write_ops::UpdateModification updateModification(update);
+            write_ops::UpdateOpEntry updateEntry(query.obj, updateModification);
+            updateEntry.setMulti(false);
+            updateEntry.setUpsert(upsert);
+            updateOp.setUpdates({updateEntry});
+
+            return updateOp.serialize({});
+        }());
+
+        const auto commandReply = commandResponse->getCommandReply();
+        uassertStatusOK(getStatusFromWriteCommandReply(commandReply));
+
+        WriteConcernResult ignoreResult;
+        auto latestOpTime = repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
+        uassertStatusOK(waitForWriteConcern(opCtx, latestOpTime, writeConcern, &ignoreResult));
+    }
+
+    /**
+     * Removes all documents which match the given query.
+     */
+    void remove(OperationContext* opCtx,
+                Query query,
+                const WriteConcernOptions& writeConcern = WriteConcerns::kMajorityWriteConcern) {
+        DBDirectClient dbClient(opCtx);
+
+        auto commandResponse = dbClient.runCommand([&] {
+            write_ops::Delete deleteOp(_storageNss);
+
+            deleteOp.setDeletes({[&] {
+                write_ops::DeleteOpEntry entry;
+
+                entry.setQ(query.obj);
+                entry.setMulti(true);
+
+                return entry;
+            }()});
+
+            return deleteOp.serialize({});
+        }());
+
+        const auto commandReply = commandResponse->getCommandReply();
+        uassertStatusOK(getStatusFromWriteCommandReply(commandReply));
+
+        WriteConcernResult ignoreResult;
+        auto latestOpTime = repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
+        uassertStatusOK(waitForWriteConcern(opCtx, latestOpTime, writeConcern, &ignoreResult));
+    }
+
+    /**
+     * Executes the specified query on the collection and calls the callback for each element.
+     * Iteration can be stopped early if the callback returns false indicating that it doesn't want
+     * to continue.
+     */
+    void forEach(OperationContext* opCtx, Query query, std::function<bool(const T&)> handler) {
+        DBDirectClient dbClient(opCtx);
+
+        auto cursor = dbClient.query(_storageNss, query);
+
+        while (cursor->more()) {
+            auto bson = cursor->next();
+            auto t = T::parse(
+                IDLParserErrorContext("PersistentTaskStore:" + _storageNss.toString()), bson);
+
+            if (bool shouldContinue = handler(t); !shouldContinue)
+                return;
+        }
+    }
+
+    /**
+     * Returns the number of documents in the store matching the given query.
+     */
+    size_t count(OperationContext* opCtx, Query query = Query()) {
+        DBDirectClient client(opCtx);
+
+        auto projection = BSON("_id" << 1);
+        auto cursor = client.query(_storageNss, query, 0, 0, &projection);
+
+        return cursor->itcount();
+    }
+
+private:
+    NamespaceString _storageNss;
+};
+
+}  // namespace mongo