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⚠️ Draft Standards Track: Core

SIP-7799: System logs

Per-block logs without associated transactions

Authors Etan Kissling (@etan-status), Gajinder Singh (@g11tech)
Created 2024-10-29
Discussion Link https://sila-magicians.org/t/sip-7799-system-logs/21497
Requires SIP-4895, SIP-6466, SIP-7708, SIP-7916, SIP-8115

Table of Contents

Abstract

This SIP defines an extension for sil_getLogs to provide logs for events that are not associated with a given transaction, such as block rewards and withdrawals.

Motivation

With SIP-7708 wallets gain the ability to use sil_getLogs to track changes to their SIL balance. However, the SIL balance may change without an explicit transaction, through block production and withdrawals. By having such operations emit block-level system logs, sil_getLogs provides a complete picture of SIL balance changes.

Specification

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119 and RFC 8174.

Fee payment logs

A log, identical to a LOG2, is issued for every transaction and appended after all other logs created by SVM execution. The fee amount incorporates the total fee charged during transaction execution, including the base fee, the priority fee, and potential blob fees.

Field Value
address 0xfffffffffffffffffffffffffffffffffffffffe (SYSTEM_ADDRESS)
topics[0] 0x7bd3aa7d673767f759ebf216e7f6c12844986c661ae6e0f1d988cf7eb7394d1d (keccak256('Fee(address,uint256)'))
topics[1] from address (zero prefixed to fill uint256)
data amount in Wei (big endian uint256)

System logs list

A new list is introduced to track all block level logs emitted from system interactions. The definition uses the Log SSZ type from SIP-6466.

system_logs = ProgressiveList[Log](
    log_0, log_1, log_2, ...)

Priority fee processing

A log SHALL be appended to the system logs list when crediting the batched SIP-8115 priority fee.

Field Value
address 0xfffffffffffffffffffffffffffffffffffffffe (SYSTEM_ADDRESS)
topics[0] 0x5dfe9c0fd3043bb299f97cfece428f0396cf8b7890c525756e4ea5c0ff7d61b2 (keccak256('PriorityRewards(address,uint256)'))
topics[1] to address (zero prefixed to fill uint256)
data amount in Wei (big endian uint256)

Withdrawal processing

A log SHALL be appended to the system logs list on every SIP-4895 withdrawal.

Field Value
address 0xfffffffffffffffffffffffffffffffffffffffe (SYSTEM_ADDRESS)
topics[0] 0x7fcf532c15f0a6db0bd6d0e038bea71d30d808c7d98cb3bf7268a95bf5081b65 (keccak256('Withdrawal(address,uint256)'))
topics[1] to address (zero prefixed to fill uint256)
data amount in Wei (big endian uint256)

Genesis processing

A log SHALL be appended to the system logs list when generating genesis blocks for networks that adopt this SIP from the beginning.

Field Value
address 0xfffffffffffffffffffffffffffffffffffffffe (SYSTEM_ADDRESS)
topics[0] 0xba2f6409ffd24dd4df8e06be958ed8c1706b128913be6e417989c74969b0b55a (keccak256('Genesis(address,uint256)'))
topics[1] to address (zero prefixed to fill uint256)
data amount in Wei (big endian uint256)

Execution block header changes

The execution block header is extended with a new field, system-logs-root.

block_header.system_logs_root = system_logs.hash_tree_root()

JSON-RPC API

Block header objects in the context of the JSON-RPC API are extended to include:

  • systemLogsRoot: DATA, 32 Bytes

Log objects in the context of the JSON-RPC API are updated as follows:

  • logIndex: QUANTITY - The additional system logs are indexed consecutively after the existing logs from transaction receipts
  • transactionIndex: QUANTITY - null is also used for system logs; pending logs can still be identified by checking the blockHash for null
  • transactionHash: DATA, 32 Bytes - null is also used for system logs

Engine API

In the engine API, the ExecutionPayload for versions corresponding to forks adopting this SIP is extended to include:

  • systemLogsRoot: DATA, 32 Bytes

As part of engine_forkchoiceUpdated, Execution Layer implementations SHALL verify that systemLogsRoot for each block matches the actual value computed from local processing. This extends on top of existing receiptsRoot validation.

Consensus ExecutionPayload changes

The consensus ExecutionPayload type is extended with a new field to store the system logs root.

class ExecutionPayload(...):
    ...
    system_logs_root: Root

Rationale

Tosilaer with SIP-7708 this SIP provides the ability for wallets to compute the exact SIL balance from logs without requiring download of every single block header and all withdrawals.

The block reward from priority fees no longer has to be summed up by processing all receipts and can be obtained from the system logs root, making it efficiently provable.

Alternatives / Future

  • The information from withdrawals is now duplicated across both the withdrawals list and the system logs. Maybe the information could be massaged into the emitted Withdrawal log data, allowing the existing withdrawals list to be retired. The current list design requires the wallet to obtain all block headers and all withdrawals to ensure they obtained all data pertaining to the observed account. Allowing them to be queried using sil_getLogs is more in line with how deposits are being tracked.

  • The log definitions themselves are subject to change. Aligning them with SRC-20 for plain credits provides consistency. For withdrawals, the log data could match the form of deposit logs and SIP-7685 request logs.

Backwards Compatibility

As a new field is added to the block header, applications assuming a specific block header layout may need updating.

Security Considerations

The emitted logs use SYSTEM_ADDRESS as their address which cannot conflict with user controlled smart contracts.

Copyright and related rights waived via CC0.

Citation

Please cite this document as:

Etan Kissling (@etan-status), Gajinder Singh (@g11tech), "SIP-7799: System logs [DRAFT]," Sila Improvement Proposals, no. 7799, October 2024. Available: https://sips.sila.org/SIPS/sip-7799.