Contract Architecture Discussion: size limits & architectural complexity.

[rjan90]

Problem Statement

The FilecoinWarmStorageService is facing multiple challenges that require architectural discussion:

1. Contract Size Limit

The FilecoinWarmStorageService is currently 25,189 bytes (613 bytes over the 24KB EIP-170 limit) even after custom errors optimization saved 3,226 bytes, and the size continues to grow with new features. Ref: #91

2. Growing Architectural Complexity

Based on discussions in yesterdays Eng-sync, the contract is accumulating responsibilities that suggest a potential need for architectural separation.

And there additional potential upcoming features that might add even more complexity, like the CDN Service allowing retrievers to pay for CDN services, and PoRep backups for example - there was a suggestion to maybe split up contract due to growing responsibilities.

Discussion

I'd like to hear everyone's thoughts and suggestions around potential architectural approaches to address these challenges.

[rjan90]

Adding a comment from @wjmelements here in Slack, to this discussion:

I think a lot can be saved by cutting down on the public view and external view methods. If some of these methods are necessary for some other contract, you can mimic UniswapV4 and provide extsload and separate that functionality into a separate contract.

[jennijuju]

#110 should bring us to a good enough place

[rjan90]

#110 should bring us to a good enough place

In the short term that definetly brought us to a good place. But with some new PRs we are already seeing that we are hitting the limit again (example: #111)

[Hany-Almnaem]

Hi @rjan90 ,
I spent some time looking in size reduction strategies and wanted to share a few ideas that might be useful.

---

Short Term (Estimated: 600–800 bytes saved)

1. Separate Provider Registry Contract (~400–500 bytes saved)

The storage provider approval logic seems self-contained. Extracting it into its own contract could help modularize and reduce size.
Example interface:

interface IProviderRegistry {
    function isApproved(address provider) external view returns (bool);
    function getProviderInfo(uint256 id) external view returns (ApprovedProviderInfo memory);
}

2. Use Assembly for Event Emissions (~30–50 bytes/event)

For frequent events like DataSetRailsCreated, RailRateUpdated, and PaymentArbitrated, emitting them using low-level log instructions.

3. Move Math to External Library

Functions like calculateStorageRatePerEpoch and calculateCacheMissRatePerEpoch could be moved to an external (not internal) library to avoid inlining.

---

Medium-Term Optimization

Adopt Uniswap V4-style extsload + Viewer Contract

As suggested by @wjmelements

---

Long-Term Architecture: Hub-and-Spoke Pattern

We could explore a Hub-and-Spoke structure ((as outlined in ConsenSys Mesh DApp Architecture Guide):

• Hub: Handles upgrade logic, access control, and base storage.

• Modules:

  • Payment (rates, beneficiaries)
  • Provider (registry, approvals)
  • Proving (challenge windows)
  • Viewer/Read module (to offload getters)
    Each submodule could remain under 10KB and interact with the Hub via delegatecall or minimal interfaces.

[aarshkshah1992]

We've started hitting the contract size limits on our WarmStorageService contract. This contract is the base for our Filecoin Synapse Service and we will add more logic to it down the road as well. It's time to solve the contract size issue in a long term way so we can add more logic to it without continuously running into the size limit issue.

We can do this by either extracting libraries out of this contract, breaking it into multiple contracts or removing sizable state getters that are not really needed or moving them to another read-only contract that we boot up for this sole purpose.

[aarshkshah1992]

@rjan90 I think it's time to prioritise this one.

[aarshkshah1992]

@wjmelements Senpai, please can you help with this one ? 🙏 We need to solve this from the ground up now so we can ship features in this contract with velocity otherwise this blocks everything else.

[wjmelements]

I can start this when I get back home, Wednesday.