@andrew_l/mongo-transaction/dist/index.mjs

Manages side effects in MongoDB transactions, rollback on failure and preventing duplicates on retries.

import { defer, isPromise, logger, assert, catchError, asyncForEach, env, noop, isFunction, isEqual, has, deepDefaults, retryOnError } from '@andrew_l/toolkit';
import { createContext, hasInjectionContext, withContext } from '@andrew_l/context';
import { MongoTransactionError } from 'mongodb';

const [injectMongoSession, provideMongoSession] = createContext("withMongoTransaction");
function useMongoSession() {
  return hasInjectionContext() ? injectMongoSession(null) : null;
}

function onMongoSessionCommitted(...args) {
  let session;
  let fn;
  if (args.length === 2) {
    [session, fn] = args;
  } else {
    session = injectMongoSession();
    fn = args[0];
  }
  const q = defer();
  const onEnded = () => {
    if (!session.transaction.isCommitted) {
      return q.resolve(void 0);
    }
    try {
      const result = fn();
      if (isPromise(result)) {
        result.then((r) => q.resolve(r)).catch(q.reject);
      } else {
        q.resolve(result);
      }
    } catch (err) {
      q.reject(err);
    }
  };
  session.once("ended", onEnded);
  const cancel = () => {
    session.off("ended", onEnded);
  };
  return {
    promise: q.promise,
    cancel
  };
}

const [injectTransactionScope, provideTransactionScope] = createContext([
  "withTransaction",
  "withTransactionControlled",
  "withMongoTransaction"
]);

class TransactionScope {
  constructor(fn) {
    this.fn = fn;
    const scope = this;
    this.run = function(...args) {
      const self = this === scope ? void 0 : this;
      return scope._run(self, ...args);
    };
  }
  /**
   * @internal
   */
  log = logger("TransactionScope");
  /**
   * @internal
   * Indicates currently ran scope
   */
  _active = false;
  /**
   * Last run error
   */
  error;
  /**
   * Last run result
   */
  result;
  run;
  /**
   * @internal
   */
  hooks = {
    committed: { byCursor: [], cursor: 0 },
    effects: { byCursor: [], cursor: 0 },
    rollbacks: { byCursor: [], cursor: 0 }
  };
  get active() {
    return this._active;
  }
  /**
   * @internal
   */
  async _run(self, ...args) {
    assert.ok(!this._active, "Cannot run while transaction active.");
    this.reset();
    this._active = true;
    const [cbError, cbResult] = await withContext(() => {
      provideTransactionScope(this);
      return catchError(this.fn.bind(self, ...args));
    })();
    if (cbError) {
      this.error = cbError;
    } else {
      const applyError = await effectsApply(this, "post");
      if (applyError) {
        this.error = applyError;
      }
      this.result = cbResult;
    }
    this._active = false;
  }
  async commit() {
    assert.ok(!this._active, "Cannot commit while transaction active.");
    assert.ok(!this.error, this.error);
    await asyncForEach(
      this.hooks.committed.byCursor,
      (h) => catchError(h.callback),
      { concurrency: 4 }
    );
    this.reset();
    this.clean();
  }
  async rollback() {
    assert.ok(!this._active, "Cannot rollback while transaction active.");
    const error = await effectsCleanup(this);
    if (error) {
      return Promise.reject(error);
    }
    await asyncForEach(
      this.hooks.rollbacks.byCursor,
      (h) => catchError(h.callback),
      { concurrency: 4 }
    );
    this.reset();
    this.clean();
  }
  reset() {
    assert.ok(!this._active, "Cannot reset while transaction active.");
    this.hooks.effects.cursor = 0;
    this.hooks.committed.cursor = 0;
    this.hooks.rollbacks.cursor = 0;
    this.result = void 0;
    this.error = void 0;
  }
  clean() {
    assert.ok(!this._active, "Cannot clean while transaction active.");
    this.hooks.effects = { byCursor: [], cursor: 0 };
    this.hooks.committed = { byCursor: [], cursor: 0 };
    this.hooks.rollbacks = { byCursor: [], cursor: 0 };
  }
}
function createTransactionScope(fn) {
  return new TransactionScope(fn);
}
async function effectsApply(scope, reason = "no reason") {
  let error;
  const onComplete = (err) => void (error = err || error);
  await asyncForEach(
    scope.hooks.effects.byCursor,
    (effect) => applyEffect(scope, effect, reason).then(onComplete),
    {
      concurrency: 4
    }
  );
  return error;
}
async function effectsCleanup(scope, reason = "no reason") {
  let error;
  const onComplete = (err) => void (error = err || error);
  await asyncForEach(
    scope.hooks.effects.byCursor,
    (effect) => cleanupEffect(scope, effect, reason).then(onComplete),
    {
      concurrency: 4
    }
  );
  return error;
}
async function applyEffect(scope, effect, reason = "no reason") {
  if (effect.cleanup) return;
  scope.log.debug(
    "Effect name = %s, flush = %s, apply by %s",
    effect.name,
    effect.flush,
    reason
  );
  const [err, effectResult] = await catchError(effect.setup);
  if (err) {
    !env.isTest && scope.log.error(
      "Effect name = %s, flush = %s apply error",
      effect.name,
      effect.flush,
      err
    );
    return err;
  }
  effect.cleanup = isFunction(effectResult) ? effectResult : noop;
  return;
}
async function cleanupEffect(scope, effect, reason = "no reason") {
  if (!effect.cleanup) return;
  scope.log.debug(
    "Effect name = %s, flush = %s, cleanup by %s",
    effect.name,
    effect.flush,
    reason
  );
  const [err] = await catchError(effect.cleanup);
  if (err) {
    !env.isTest && scope.log.error(
      "Effect name = %s, flush = %s, cleanup error",
      effect.name,
      effect.flush,
      err
    );
    return err;
  }
  effect.cleanup = void 0;
}

async function useTransactionEffect(setup, options = {}) {
  const scope = injectTransactionScope();
  const { cursor, byCursor } = scope.hooks.effects;
  const effectConfig = byCursor[cursor] ?? {};
  const flush = options?.flush || "pre";
  const name = options?.name || `Effect #${cursor + 1}`;
  const dependencies = options.dependencies ?? [];
  const prevDependencies = effectConfig.dependencies;
  byCursor[cursor] = {
    ...effectConfig,
    dependencies,
    flush,
    name,
    setup
  };
  if (dependencies && prevDependencies) {
    if (!isEqual(dependencies, prevDependencies)) {
      scope.log.debug(
        "Effect name = %s, flush = %s, caused by dependencies",
        name,
        flush,
        {
          prevDependencies,
          newDependencies: dependencies
        }
      );
      await scheduleEffect(scope, cursor);
    }
  } else {
    scope.log.debug(
      "Effect name = %s, flush = %s, caused by missing dependencies",
      name,
      flush
    );
    await scheduleEffect(scope, cursor);
  }
  scope.hooks.effects.cursor++;
}
async function scheduleEffect(scope, cursor) {
  const { byCursor } = scope.hooks.effects;
  const effect = byCursor[cursor];
  const cleanupErr = await cleanupEffect(scope, effect, "schedule pre");
  if (cleanupErr) {
    return Promise.reject(cleanupErr);
  }
  if (effect.flush === "pre") {
    const err = await applyEffect(scope, effect, "schedule pre");
    if (err) {
      return Promise.reject(err);
    }
  }
}

function onCommitted(callback, dependencies) {
  const scope = injectTransactionScope();
  const { cursor, byCursor } = scope.hooks.committed;
  const config = byCursor[cursor];
  if (dependencies && config?.dependencies) {
    if (!isEqual(dependencies, config.dependencies)) {
      scope.log.debug("OnCommitted caused by dependencies", {
        prevDependencies: config.dependencies,
        newDependencies: dependencies,
        cursor
      });
      byCursor[cursor] = { callback, dependencies };
    }
  } else {
    scope.log.debug("OnCommitted caused by missing dependencies", { cursor });
    byCursor[cursor] = { callback, dependencies };
  }
  scope.hooks.committed.cursor++;
  return () => {
    byCursor[cursor].callback = noop;
  };
}

function onRollback(callback, dependencies) {
  const scope = injectTransactionScope();
  const { cursor, byCursor } = scope.hooks.rollbacks;
  const config = byCursor[cursor];
  if (dependencies && config?.dependencies) {
    if (!isEqual(dependencies, config.dependencies)) {
      scope.log.debug("OnCommitted caused by dependencies", {
        prevDependencies: config.dependencies,
        newDependencies: dependencies,
        cursor
      });
      byCursor[cursor] = { callback, dependencies };
    }
  } else {
    scope.log.debug("OnCommitted caused by missing dependencies", { cursor });
    byCursor[cursor] = { callback, dependencies };
  }
  scope.hooks.committed.cursor++;
  return () => {
    byCursor[cursor].callback = noop;
  };
}

function isTransactionAborted(transaction) {
  return transaction?.state === "TRANSACTION_ABORTED";
}
function isTransactionCommittedEmpty(transaction) {
  return transaction?.state === "TRANSACTION_COMMITTED_EMPTY";
}
function isMongoClientLike(value) {
  return has(value, ["startSession"]) && isFunction(value.startSession);
}

const DEF_SESSION_OPTIONS = Object.freeze({
  defaultTransactionOptions: {
    readPreference: "primary",
    readConcern: { level: "local" },
    writeConcern: { w: "majority" }
  }
});
function withMongoTransaction(connectionOrOptions, maybeFn, maybeOptions) {
  const {
    connection: connectionValue,
    fn,
    sessionOptions = {},
    timeoutMS
  } = prepareOptions(connectionOrOptions, maybeFn, maybeOptions);
  return async function(...args) {
    const connection = isFunction(connectionValue) ? await connectionValue() : connectionValue;
    const session = await connection.startSession(
      sessionOptions
    );
    const scope = createTransactionScope(function(...args2) {
      provideMongoSession(session);
      return fn.call(this, session, ...args2);
    });
    const timeoutAt = timeoutMS ? Date.now() + timeoutMS : 0;
    const timeoutError = new MongoTransactionError(
      "Transaction client-side timeout"
    );
    let [transactionError, transactionResult] = await catchError(
      () => session.withTransaction(async () => {
        if (timeoutAt && timeoutAt < Date.now()) {
          return Promise.reject(timeoutError);
        }
        await scope.run.apply(this, args);
        if (scope.error) {
          return Promise.reject(scope.error);
        }
      })
    );
    const { result } = scope;
    await session.endSession().catch(noop);
    if (transactionResult === void 0 && isTransactionCommittedEmpty(session.transaction)) ; else if (isTransactionAborted(session.transaction) && transactionResult === void 0 && transactionError === void 0) {
      transactionError = new MongoTransactionError(
        "Transaction is explicitly aborted"
      );
    }
    if (transactionError) {
      await scope.rollback();
      return Promise.reject(transactionError);
    }
    await scope.commit();
    return result;
  };
}
function prepareOptions(connectionOrOptions, maybeFn, maybeOptions) {
  let options;
  if (isFunction(connectionOrOptions) || isMongoClientLike(connectionOrOptions)) {
    options = {
      ...maybeOptions || {},
      connection: connectionOrOptions,
      fn: maybeFn
    };
  } else {
    options = connectionOrOptions;
  }
  return deepDefaults(options, {
    sessionOptions: DEF_SESSION_OPTIONS
  });
}

function withTransaction(fn, {
  beforeRetryCallback,
  shouldRetryBasedOnError = () => true,
  maxAttempts,
  maxRetriesNumber = 5,
  delayFactor = 0,
  delayMaxMs = 1e3,
  delayMinMs = 100
} = {}) {
  return async function(...args) {
    const scope = createTransactionScope(fn);
    await retryOnError(
      {
        beforeRetryCallback,
        shouldRetryBasedOnError,
        maxAttempts,
        maxRetriesNumber,
        delayFactor,
        delayMaxMs,
        delayMinMs
      },
      async () => {
        await scope.run.apply(this, args);
        if (scope.error) {
          return Promise.reject(scope.error);
        }
      }
    )().catch(noop);
    const { error, result } = scope;
    if (error) {
      await scope.rollback();
      return Promise.reject(error);
    } else {
      await scope.commit();
    }
    return result;
  };
}

function withTransactionControlled(fn) {
  const scope = createTransactionScope(fn);
  const controlled = {
    run(...args) {
      const self = this === controlled ? void 0 : this;
      return scope.run.apply(self, args);
    },
    commit() {
      return scope.commit();
    },
    rollback() {
      return scope.rollback();
    },
    get active() {
      return scope.active;
    },
    get result() {
      return scope.result;
    },
    get error() {
      return scope.error;
    }
  };
  return controlled;
}

export { onCommitted, onMongoSessionCommitted, onRollback, useMongoSession, useTransactionEffect, withMongoTransaction, withTransaction, withTransactionControlled };
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