WASM UDF support

[snork-alt]

📝 Description:

This is a proposal for a new feature in Dozer Core, to enhance the functionality by allowing users to define a SQL User Defined Function (UDF) implemented in WASM (AssemblyScript)

🌟 Feature Details:

Users should be able to define a WASM UDF usable in Dozer SQL.

In order to implement an UDF a user should:

• Add a .wasm file to the project folder (for example in the directory udfs/wasm/my_function.wasm)
• Add the following configuration lines to dozer-config.yaml:

udfs:
  wasm:
     my_function: udfs/wasm/my_function

Upon startup Dozer should load the wasm function and make it available in Dozer SQL. my_function() should now be usable from SQL as:

SELECT my_function(filed1, field2) FROM ...

[snork-alt]

/bounty $600

[algora-pbc]

💎 $600 bounty • Dozer Data

Steps to solve:

1. Start working: Comment /attempt #1653 with your implementation plan
2. Submit work: Create a pull request including /claim #1653 in the PR body to claim the bounty
3. Receive payment: 100% of the bounty is received 2-5 days post-reward. Make sure you are eligible for payouts

❗ Important guidelines:

• To claim a bounty, you need to provide a short demo video of your changes in your pull request
• If anything is unclear, ask for clarification before starting as this will help avoid potential rework
• Low quality AI PRs will not receive review and will be closed
• Do not ask to be assigned unless you've contributed before

Thank you for contributing to getdozer/dozer!

Attempt	Started (UTC)	Solution	Actions
🟢 @sevencat2004	Jun 03, 2026, 04:19:47 AM	#2500	Reward
🟢 @singhaditya21	Jun 15, 2026, 07:04:36 AM	#2502	Reward
🟢 @mySebbe	May 16, 2026, 11:56:23 PM	#2491	Reward
🟢 @0xPoe	Jun 19, 2023, 03:35:39 PM	WIP
🟢 @varshith257	May 19, 2024, 04:35:43 PM	WIP
🟢 @tachyonicbytes	Jun 19, 2023, 11:46:33 PM	#1654	Reward

[0xPoe]

/attempt #1653

I will give it a try.

[jemilu2]

@hi-rustin, use the attempt comment above to indicate you've started working on it.

[0xPoe]

/attempt #1653

[tachyonicbytes]

Hi! I also wanted to explore this issue

/attempt #1653

[algora-pbc]

Note: The user @hi-rustin is already attempting to complete issue #1653 and claim the bounty. If you attempt to complete the same issue, there is a chance that @hi-rustin will complete the issue first, and be awarded the bounty. We recommend discussing with @hi-rustin and potentially collaborating on the same solution versus creating an alternate solution.

[algora-pbc]

💡 @tachyonicbytes submitted a pull request that claims the bounty. You can visit your org dashboard to reward.

[0xPoe]

@tachyonicbytes Perhaps before contributing to the open source community you need to ask the original people if they have started work. Otherwise, it's going to be an endless race for speed :(

[varshith257]

/attempt #1653

Algora profile	Completed bounties	Tech	Active attempts	Options
@varshith257	1 bounty from 1 project	TypeScript, Go	#1659	Cancel attempt

[mySebbe]

/attempt #1653

[jamilahmadzai]

/attempt #1653

Plan:

• Add repo-native !Wasm UDF config support and schema coverage.
• Wire WASM UDF parsing through the SQL expression builder behind an optional wasm feature.
• Validate exported function signatures before execution and infer return/nullability metadata.
• Execute numeric WASM UDFs with checked casts, null propagation, and focused unit coverage for success/error paths.
• Propagate the optional feature through dozer-sql/dozer-cli so users can enable it cleanly.

[gnomedev-gvs]

/attempt #1653

[ksushant6566]

/attempt #1653

I am implementing WebAssembly UDFs behind an optional wasm feature, wired through the existing UDF configuration, SQL expression builder and CLI. The implementation uses a bounded Wasmi runtime, infers numeric parameter/result types from the module export, propagates SQL NULLs, checks numeric conversions, and creates a fresh instance per row to avoid hidden mutable state across streaming changes. Fuel, memory and table limits bound module execution.

The validation includes SQL/config/runtime tests and a real AssemblyScript module, including its env.abort import. I will include the short running demo requested by the bounty instructions. This is an AI-assisted implementation; the PR will state the actual results and supported ABI/limitations.