Geth Log Cruncher

A command-line tool for converting unstructured Ethereum Geth logs into machine-readable JSONL. It parses raw log files into structured data suitable for analysis, database ingestion, or processing with other CLI tools like jq.

Installation

Install directly from crates.io using Cargo:

cargo install geth-log-cruncher

Usage

Basic example

geth-log-cruncher /path/to/your/geth.log > parsed_logs.jsonl

Specifying a year

For archived log files where the timestamp year isn't present or isn't the current year, use --year:

geth-log-cruncher /path/to/archive/geth-2023.log --year 2023 > parsed_2023_logs.jsonl

Filtering with jq

Example: show only DEBUG-level logs:

geth-log-cruncher /path/to/your/geth.log | jq 'select(.level == "DEBUG")'

Example pipeline

Write parsed output to a file, then count INFO logs:

geth-log-cruncher /var/log/geth.log > /tmp/geth.jsonl
jq '.level' /tmp/geth.jsonl | grep -c '"INFO"'

Output format

Typical fields:

• timestamp — ISO 8601 timestamp (reconstructed using --year when needed).
• level — log level when present (e.g., INFO, WARN, DEBUG).
• message — the raw log message text.
• details — an object of parsed KV pairs extracted from the message (flexible and sparse).

A sample parsed line might look like:

{
  "timestamp": "2023-07-01T12:34:56Z",
  "level": "DEBUG",
  "message": "failed to download block",
  "details": {
    "block": "0xabc123",
    "peer": "12D3K..."
  }
}

Contributing

PRs and issues are welcome. If you add parsers for more Geth subsystems or improve performance, please open an issue first to discuss the approach.

License

This project is licensed under the MIT License.