Parse and filter cargo build logs to extract errors, warnings, and diagnostics with regex-based filtering. Use when debugging Rust projects, analyzing cargo build output, filtering errors by file path or message pattern, or helping users understand compilation failures. Triggers on cargo build errors, rustc diagnostics, Rust compilation issues, or requests to parse .log files from cargo.
The Cargo Log Parser is a specialized Claude skill designed to streamline the debugging process for Rust developers. It efficiently parses and filters cargo build logs using regex-based logic to extract precise errors, warnings, and diagnostics. By transforming verbose compilation output into structured, actionable data, it helps developers quickly identify root causes and resolve Rust compilation issues.
Use Cases
Targeted Debugging: Quickly isolate specific Rust compiler errors (e.g., borrow checker or name resolution issues) by filtering logs using error codes like E0425 or E0308.
Large Project Log Management: Filter massive build outputs by file path regex to focus only on diagnostics relevant to specific modules or test suites.
CI/CD Pipeline Analysis: Integrate with automated workflows to generate structured JSON summaries of build failures, making it easier to track and report recurring issues.
Code Quality Audits: Use the grouping feature to categorize warnings and errors by file or type, helping teams identify patterns of technical debt or common coding mistakes.
name
cargo-log-parser
description
Parse and filter cargo build logs to extract errors, warnings, and diagnostics with regex-based filtering. Use when debugging Rust projects, analyzing cargo build output, filtering errors by file path or message pattern, or helping users understand compilation failures. Triggers on cargo build errors, rustc diagnostics, Rust compilation issues, or requests to parse .log files from cargo.
Cargo Log Parser
Parse cargo build logs to extract and filter errors/warnings with precise log boundaries.
Quick Start
# From file
python scripts/cargo_log_parser.py build.log --errors
# From stdin (pipe from cargo)
cargo build 2>&1 | python scripts/cargo_log_parser.py --errors
Key Filters
Flag
Purpose
Example
-e, --errors
Errors only
--errors
-w, --warnings
Warnings only
--warnings
-f, --file PATTERN
Filter by file path regex
--file "tests/.*"
-m, --message PATTERN
Filter by message regex
--message "cannot find"
-c, --code PATTERN
Filter by error code
--code "E0425"
Output Modes
Flag
Output Style
(default)
Detailed LLM-friendly format with context
--stream
Compact one-line-per-diagnostic
--raw
Original log text for matches only
--json
Structured JSON output
-v, --verbose
Include raw log text in output
Common Patterns
# Errors in test files only
python scripts/cargo_log_parser.py build.log --errors --file "tests/.*"
# Find "not found" errors
python scripts/cargo_log_parser.py build.log --errors --message "cannot find|not found"
# All E04xx errors (name resolution)
python scripts/cargo_log_parser.py build.log --code "E04\d\d"
# Group errors by file
python scripts/cargo_log_parser.py build.log --errors --group-by-file
# Group by error code
python scripts/cargo_log_parser.py build.log --errors --group-by-code
# Quick summary
python scripts/cargo_log_parser.py build.log --summary
Python API
from cargo_log_parser import CargoLogParser, LogQuery, DiagnosticLevel
parser = CargoLogParser()
parsed = parser.parse_file("build.log")
query = LogQuery(parsed)
# Filter errors
errors = query.find_errors(file_pattern=r"tests/.*", message_pattern=r"cannot find")
# Get exact log boundaries
for error in errors:
bounds = query.get_error_boundaries(error)
print(f"Lines {bounds['line_start']}-{bounds['line_end']}")
print(bounds['raw_text'])
# Group and analyze
by_file = query.group_by_file(level=DiagnosticLevel.ERROR)
by_code = query.group_by_code()
