@mcma/aws-dynamodb/dist/lib/dynamo-db-mutex.js

Node module with code for using DynamoDB as the backing data storage for MCMA API handlers and workers.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.DynamoDbMutex = void 0;
const lib_dynamodb_1 = require("@aws-sdk/lib-dynamodb");
const data_1 = require("@mcma/data");
class DynamoDbMutex extends data_1.DocumentDatabaseMutex {
    dc;
    tableDescription;
    _versionId;
    constructor(dc, tableDescription, mutexName, mutexHolder, lockTimeout = 300000, logger) {
        super(mutexName, mutexHolder, lockTimeout, logger);
        this.dc = dc;
        this.tableDescription = tableDescription;
        this._versionId = (Math.random() * 2147483648 << 0).toString();
    }
    get versionId() {
        return this._versionId;
    }
    generateTableKey() {
        const Key = {};
        if (this.tableDescription.keyNames.sort) {
            Key[this.tableDescription.keyNames.partition] = "Mutex";
            Key[this.tableDescription.keyNames.sort] = this.mutexName;
        }
        else {
            Key[this.tableDescription.keyNames.partition] = "Mutex-" + this.mutexName;
        }
        return Key;
    }
    generateTableItem() {
        const tableItem = {
            mutexHolder: this.mutexHolder,
            versionId: this.versionId,
            timestamp: Date.now()
        };
        if (this.tableDescription.keyNames.sort) {
            tableItem[this.tableDescription.keyNames.partition] = "Mutex";
            tableItem[this.tableDescription.keyNames.sort] = this.mutexName;
        }
        else {
            tableItem[this.tableDescription.keyNames.partition] = "Mutex-" + this.mutexName;
        }
        return tableItem;
    }
    async getLockData() {
        const record = await this.dc.send(new lib_dynamodb_1.GetCommand({
            TableName: this.tableDescription.tableName,
            Key: this.generateTableKey(),
            ConsistentRead: true
        }));
        // sanity check which removes the record from DynamoDB in case it has incompatible structure. Only possible
        // if modified externally, but this could lead to a situation where the lock would never be acquired.
        if (record.Item && (!record.Item.mutexHolder || !record.Item.versionId || !record.Item.timestamp)) {
            await this.dc.send(new lib_dynamodb_1.DeleteCommand({
                TableName: this.tableDescription.tableName,
                Key: this.generateTableKey(),
            }));
            delete record.Item;
        }
        return record.Item;
    }
    async putLockData() {
        const value = {
            TableName: this.tableDescription.tableName,
            Item: this.generateTableItem(),
            Expected: {
                resource_id: {
                    Exists: false
                }
            }
        };
        value.Expected[this.tableDescription.keyNames.partition] = { Exists: false };
        await this.dc.send(new lib_dynamodb_1.PutCommand(value));
    }
    async deleteLockData(versionId) {
        await this.dc.send(new lib_dynamodb_1.DeleteCommand({
            TableName: this.tableDescription.tableName,
            Key: this.generateTableKey(),
            ConditionExpression: "#v = :v",
            ExpressionAttributeNames: { "#v": "versionId" },
            ExpressionAttributeValues: { ":v": versionId }
        }));
    }
}
exports.DynamoDbMutex = DynamoDbMutex;