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(fetched from here on 2026-02-11)

JIP-1: Debug message host call

A host call for passing a debugging message from the service/authorizer to the hosting environment for logging to the node operator.

Host-call specification​

Index: 100

Name: log

Gas usage: 10 (same as host-call with bad index)

Input registers: φ7⋯+5\varphi_{7\dots+5}

  • level = φ7\varphi_7
  • target = ∅\varnothing if φ8=0∧φ9=0\varphi_8 = 0 \wedge \varphi_9 = 0, otherwise μφ8⋯+φ9\mu_{\varphi_8\dots+\varphi_9}
  • message = μφ10⋯+φ11\mu_{\varphi_{10}\dots+\varphi_{11}}

Output registers: φ7′\varphi'_7

  • φ7′\varphi'_7 = WHAT. WHAT is always returned so that authorizer/service behaviour is the same whether or not this JIP is implemented.

Side-effects​

No side-effects if memory access is invalid.

Otherwise, express a message to user according to the user-agent.

Suggestions & examples​

Levels definition​

  • 0: User agent displays as fatal error ⛔️
  • 1: User agent displays as warning ⚠️
  • 2: User agent displays as important information ℹ️
  • 3: User agent displays as helpful information 💁
  • 4: User agent displays as pedantic information 🪡

Display format for console logging​

Note that <CORE> is assumed to be the integer index of the core on which the PVM is executing, which may not exist (e.g. in the Accumulate logic).

Note that <SERVICE_ID> is assumed to be the integer index of the service for which the PVM is executing, which may not exist (e.g. in the Is-Authorized logic).

<YYYY-MM-DD hh-mm-ss> <LEVEL>[@<CORE>]?[#<SERVICE_ID>]? [<TARGET>]? <MESSAGE>

Example log item​

2025/01/01 12:10:42 DEBUG@1#42 bootstrap-refine Hello world!

Format for JSON logging​

{
    "time": "<YYYY-MM-DD hh-mm-ss>",
    "level": "<LEVEL>",
    "message": "<MESSAGE>",
    "target": "<TARGET>" | null
    "service": "<SERVICE_ID>" | null
    "core": "<CORE>" | null
}