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Show HN: DBOS TypeScript – Lightweight Durable Execution Built on Postgres
Hi HN - Peter from DBOS here with my co-founder Qian (qianl_cs)
Today we want to share our TypeScript library for lightweight durable execution. We’ve been working on it since last year and recently released v2.0 with a ton of new features and major API overhaul.
https://github.com/dbos-inc/dbos-transact-ts https://github.com/dbos-inc/dbos-transact-ts
Durable execution means persisting the execution state of your program while it runs, so if it is ever interrupted or crashes, it automatically resumes from where it left off.
Durable execution is useful for a lot of things:
- Orchestrating long-running or business-critical workflows so they seamlessly recover from any failure.
- Running reliable background jobs with no timeouts.
- Processing incoming events (e.g. from Kafka) exactly once
- Running a fault-tolerant distributed task queue
- Running a reliable cron scheduler
- Operating an AI agent, or anything that connects to an unreliable or non-deterministic API.
What’s unique about DBOS’s take on durable execution (compared to, say, Temporal) is that it’s implemented in a lightweight library that’s totally backed by Postgres. All you have to do to use DBOS is “npm install” it and annotate your program with decorators. The decorators store your program’s execution state in Postgres as it runs and recover it if it crashes. There are no other dependencies you have to manage, no separate workflow server–just your program and Postgres.
One big advantage of this approach is that you can add DBOS to ANY TypeScript application–it’s just a library. For example, you can use DBOS to add reliable background jobs or cron scheduling or queues to your Next.js app with no external dependencies except Postgres.
Also, because it’s all in Postgres, you get all the tooling you’re familiar with: backups, GUIs, CLI tools–it all just works.
Want to try DBOS out? Initialize a starter app with:
npx @dbos-inc/create -t dbos-node-starter
Then build and start your app with:
npm install
npm run build
npm run start
Also check out the docs: https://docs.dbos.dev/ https://docs.dbos.dev/
We'd love to hear what you think! We’ll be in the comments for the rest of the day to answer any questions you may have.
- 5Qn8mNbc2FNCiVV 2y agoIs there a way to use it without decorators?
- qianli_cs 2y agoHello! I'm a co-founder at DBOS here and I'm happy to answer any questions :)
- ilove196884 2y agoI know this this might sound scripted or can be considered cliche but what is the use case for DBOS.
- qianli_cs 2y agoThe main use case is to build reliable programs. For example, orchestrating long-running workflows, running cron jobs, and orchestrating AI agents with human-in-the-loop. DBOS makes external asynchronous API calls reliable and crashproof, without needing to rely on an external orchestration service.
- sarahdellysse 2y agoHi there, I think I might have found a typo in your example class in the github README. In the class's `workflow` method, shouldn't we be `await`-ing those steps?
- qianli_cs 2y agoNice catch. Fixing it :)
- gbuk2013 2y agoFYI the “Build Crashproof Apps” button in your docs doesn’t do anything.
- qianli_cs 2y agoYou'll need to click either the Python or TypeScript icon. We support both languages and will add more icons there.
- 2y ago
- psadri 2y agoWhere is the state stored? In my own pg instance? Or is it stored somewhere in the cloud? Also, a small sample code snippet would be helpful.
- KraftyOne 2y agoThe state can be stored in any Postgres instance, either locally or in any cloud. For code, here's the bare minimum code example for a workflow: class Example { @DBOS.step() static async step_one() { ... } @DBOS.step() static async step_two() { ... } @DBOS.workflow() static async workflow() { await Example.step_one() await Example.step_two() } } The steps can be any TypeScript function. Then we have a bunch more examples in our docs: https://docs.dbos.dev/ https://docs.dbos.dev/. Or if you want to try it yourself download a template: npx @dbos-inc/create
- psadri 2y agoAre there any constraints around which functions can be turned into steps? I assume their state (arguments?) need to be serializable? Also, what happens with versioning? What if I want to deploy new code?
- KraftyOne 2y agoYeah, the arguments and return values of steps have to be serializable to JSON. For versioning, each workflow is tagged with the code version that ran it, and we recommend recovering workflows on an executor running the same code version as what the workflow started on. Docs for self hosting: https://docs.dbos.dev/typescript/tutorials/development/self-hosting https://docs.dbos.dev/typescript/tutorials/development/self-.... In our hosted service (DBOS Cloud) this is all done automatically.
- CMCDragonkai 2y agoIf you were to use cbor, you could support binary values more easily.
- purpleinfs 2y agonice work
- CMCDragonkai 2y agoCould you genericise the requirement in postgresql and provide a storage interface we could plug into? I think I have a use for this in Polykey (https://GitHub.com/MatrixAI/Polykey https://GitHub.com/MatrixAI/Polykey) but we use rocksdb (transactional key value embedded db).
- CMCDragonkai 2y agoAlso this reminds me of orthogonal persistence https://wiki.c2.com/?TransparentPersistence https://wiki.c2.com/?TransparentPersistence Did you do literature research of Smalltalk?
- KraftyOne 2y agoThat's definitely worth considering! The core algorithms can work with any data store. That said, we're focused on Postgres right now because of its incredible support and popularity.
- CMCDragonkai 2y agoYou could imagine this working well for cloudflare workers - especially with time limits on execution. (Or with even aws compute market)
- jauntywundrkind 2y agoLoved the Supabase coverage from a month ago, showing under the hood what DBOS is storing & how the data flow works on it. It made real what DBOS was for me, clicked; before DBOS felt very abstract to me. https://supabase.com/blog/durable-workflows-in-postgres-dbos https://supabase.com/blog/durable-workflows-in-postgres-dbos https://news.ycombinator.com/item?id=42379974 https://news.ycombinator.com/item?id=42379974
- mfrye0 2y agoI see the example for running a distributed task queue. The docs aren't so clear though for running a distributed workflow, apart from the comment about using a vm id and the admin API. We use spot instances for most things to keep costs down and job queues to link steps. Can you provide an example of a distributed workflow setup?
- KraftyOne 2y agoGot it! What specifically are you looking for? If you launch multiple DBOS instances connected to the same Postgres database, they'll automatically form a distributed task queue, dividing new work as it arrives on the queue. If you're looking for a lightweight deployment environment, we also have a hosted solution (DBOS Cloud).
- chatmasta 2y agoDo you consider ”durability” to include idempotency? How can you guarantee that without requiring the developer to specify a (verifiable) rollback procedure for each “step?” If Step 1 inserts a new purchase into my local DB, and Step 2 calls the Stripe API to “create a new purchase,” what if Step 2 fails (even after retries, eg maybe my code is using the wrong URL or Stripe banned me)? Maybe you haven’t “committed” the transaction yet, but I’ve got a row in my database saying a purchase exists. Should something clean this up? Is it my responsibility to make sure that row includes something like a “transaction ID” provided by DBOS? It just seems that the “durability” guarantees get less reliable as you add more dependencies on external systems. Or at least, the reliability is subject to the interpretation of whichever application code interacts with the result of these workflows (e.g. the shipping service must know to ignore rows in the local purchase DB if they’re not linked to a committed DBOS transaction).
- KraftyOne 2y agoYes, if your workflow interacts with multiple external systems and you need it to fully back out and clean up after itself after a step fails, you'll need backup steps--this is basically a saga pattern. Where DBOS helps is in ensuring the entire workflow, including all backup steps, always run. So if your service is interrupted and that causes the Stripe call to fail, upon restart your program will automatically retry the Stripe call and if that doesn't work, back out and run the step that closes out the failed purchase.
- swyx 2y ago> What’s unique about DBOS’s take on durable execution (compared to, say, Temporal) is that it’s implemented in a lightweight library that’s totally backed by Postgres. All you have to do to use DBOS is “npm install” it and annotate your program with decorators. The decorators store your program’s execution state in Postgres as it runs and recover it if it crashes. There are no other dependencies you have to manage, no separate workflow server–just your program and Postgres. this is good until you the postgres server fills up with load and need to scale up/fan out work to a bunch of workers? how do you handle that? (disclosure, former temporal employee, but also no hate meant, i'm all for making more good orcehstration choices)
- KraftyOne 2y agoThat's a really good question! Because DBOS is backed by Postgres, it scales as well as Postgres does, so 10K+ steps per second with a large database server. That's good for most workloads. Past that, you can split your workload into multiple services or shard it. Past that, you've probably outscaled any Postgres-based solution (very few services need this scale). The big advantages of using Postgres are: 1. Simpler architecturally, as there are no external dependencies. 2. You have complete control over your execution state, as it's all on tables on your Postgres server (docs for those tables: https://docs.dbos.dev/explanations/system-tables#system-tables https://docs.dbos.dev/explanations/system-tables#system-tabl...)
- reissbaker 2y agoUnaffiliated with DBOS but I agree that Postgres will scale much further than most startups will ever need! Even Meta still runs MySQL under the hood (albeit with a very thick layer of custom ORM).
- swyx 2y agoyeah its not really about steps per second, its about if steps have heavy processing workload each, eg you dont want to clog up your postgres with a bunch of media processing or basically literally anything long running, which is the point of a separate workflow engine
- latchkey 2y agoWhy typeorm over something like https://mikro-orm.io/ https://mikro-orm.io/?
- qianli_cs 2y agoIn addition to TypeORM, DBOS supports several popular ORMs: - Drizzle (we're also a sponsor to Drizzle): https://docs.dbos.dev/typescript/tutorials/orms/using-drizzle https://docs.dbos.dev/typescript/tutorials/orms/using-drizzl... - Knex: https://docs.dbos.dev/typescript/tutorials/orms/using-knex https://docs.dbos.dev/typescript/tutorials/orms/using-knex - Prisma: https://docs.dbos.dev/typescript/tutorials/orms/using-prisma https://docs.dbos.dev/typescript/tutorials/orms/using-prisma More ORM support is on the way.
- latchkey 2y agoWhy not always default to using transactions?
- qianli_cs 2y agoDBOS always uses transactions to perform database operations. If you're writing a function that performs database operations, you can use the @DBOS.transaction() decorator to wrap the function so that DBOS's bookkeeping records commit in the same transaction as your operation. However, if you're interfacing with a third-party API, then that wouldn't be part of a database transaction (you'll use @DBOS.step instead). The reason is that you don't want to hold database locks when you're not performing database operations.
- darkteflon 2y agoWhat is the determinism constraint? I noticed it mentioned several times in blog posts, but one of the use-cases mentioned here is for use with LLMs, which produce non-deterministic outputs.
- KraftyOne 2y agoGreat question! A workflow should be deterministic: if called multiple times with the same inputs, it should invoke the same steps with the same inputs in the same order. But steps don't have be deterministic, they can invoke LLMs, third party APIs, or any other operation. Docs page on determinism: https://docs.dbos.dev/typescript/tutorials/workflow-tutorial#determinism https://docs.dbos.dev/typescript/tutorials/workflow-tutorial...
- atsbbg 2y agoWhat are the limits on Retroaction? Can Retroactive changes revise history? For example, if I change the code / transactions in a step, how do you reconcile what state to prepare for which transactions. For example, you'll need to reconcile deleted and duplicated calls to the DB?
- KraftyOne 2y agoGenerally we recommend against retroaction--the assumed model is that every workflow finishes on the code version it started. This is managed automatically in our hosted version (DBOS Cloud) and there's an API for self-hosting: https://docs.dbos.dev/typescript/tutorials/development/self-hosting https://docs.dbos.dev/typescript/tutorials/development/self-... That said, we know sometimes you have to do surgery on a long-running workflow, and we're looking at adding better tooling for it. It's completely doable because all the state is stored in Postgres tables (https://docs.dbos.dev/explanations/system-tables https://docs.dbos.dev/explanations/system-tables).
- e12e 2y agoInteresting idea. It seems like zodb (https://zodb.org https://zodb.org) might enable some similar things for python - by simply being an object database? Is it possible to mix typescript and python steps?
- daralthus 2y agoSo this is like aws step functions and cloudflare workflows and temporal? What are the differences, how is deployment handled?