Sarif Parsing

SARIF Parsing

Parse, analyze, and process SARIF files from static analysis tools. Out of scope: running scans (use CodeQL/Semgrep skills), writing rules, analyzing source code directly.

SARIF Structure Overview

SARIF 2.1.0 is the current OASIS standard:

sarifLog
├── version: "2.1.0"
└── runs[]
    ├── tool
    │   ├── driver
    │   │   ├── name (required)
    │   │   ├── version
    │   │   └── rules[]
    │   └── extensions[]
    ├── results[]
    │   ├── ruleId
    │   ├── level (error/warning/note)
    │   ├── message.text
    │   ├── locations[]
    │   │   └── physicalLocation
    │   │       ├── artifactLocation.uri
    │   │       └── region (startLine, startColumn, etc.)
    │   ├── fingerprints{}
    │   └── partialFingerprints{}
    └── artifacts[]

Why Fingerprinting Matters

Fingerprints hash content (code snippet, rule ID, relative location) to create stable identifiers regardless of environment. Without them, baseline comparison, regression detection, and suppression all fail — because tools report different paths across environments.

Tool Selection

Quick Analysis with jq

# Count total findings
jq '[.runs[].results[]] | length' results.sarif

# List all triggered rule IDs
jq '[.runs[].results[].ruleId] | unique' results.sarif

# Extract errors only
jq '.runs[].results[] | select(.level == "error")' results.sarif

# Findings with file locations
jq '.runs[].results[] | {
  rule: .ruleId,
  message: .message.text,
  file: .locations[0].physicalLocation.artifactLocation.uri,
  line: .locations[0].physicalLocation.region.startLine
}' results.sarif

# Count per rule at error level
jq '[.runs[].results[] | select(.level == "error")] | group_by(.ruleId) | map({rule: .[0].ruleId, count: length})' results.sarif

# Filter by specific file
jq --arg file "src/auth.py" '.runs[].results[] | select(.locations[].physicalLocation.artifactLocation.uri | contains($file))' results.sarif

Python with pysarif

from pysarif import load_from_file, save_to_file

sarif = load_from_file("results.sarif")
for run in sarif.runs:
    for result in run.results:
        print(f"  [{result.level}] {result.rule_id}: {result.message.text}")
        if result.locations:
            loc = result.locations[0].physical_location
            if loc and loc.artifact_location:
                print(f"    File: {loc.artifact_location.uri}:{loc.region.start_line if loc.region else '?'}")

save_to_file(sarif, "modified.sarif")

Python with sarif-tools

from sarif import loader

sarif_data = loader.load_sarif_file("results.sarif")
sarif_set = loader.load_sarif_files(["tool1.sarif", "tool2.sarif"])  # multi-file

report = sarif_data.get_report()
errors = report.get_issue_type_histogram_for_severity("error")

sarif-tools CLI:

sarif summary results.sarif
sarif ls --level error results.sarif
sarif diff baseline.sarif current.sarif     # find new/fixed issues
sarif csv results.sarif > results.csv
sarif html results.sarif > report.html

Aggregating Multiple SARIF Files

import json

def aggregate_sarif_files(sarif_paths: list[str]) -> dict:
    aggregated = {
        "version": "2.1.0",
        "$schema": "https://json.schemastore.org/sarif-2.1.0.json",
        "runs": []
    }
    for path in sarif_paths:
        with open(path) as f:
            aggregated["runs"].extend(json.load(f).get("runs", []))
    return aggregated

def deduplicate_results(sarif: dict) -> dict:
    """Remove duplicates based on fingerprints, falling back to rule+location key."""
    seen = set()
    for run in sarif["runs"]:
        unique = []
        for result in run.get("results", []):
            fp = None
            if result.get("partialFingerprints"):
                fp = tuple(sorted(result["partialFingerprints"].items()))
            elif result.get("fingerprints"):
                fp = tuple(sorted(result["fingerprints"].items()))
            else:
                loc = result.get("locations", [{}])[0]
                phys = loc.get("physicalLocation", {})
                fp = (result.get("ruleId"),
                      phys.get("artifactLocation", {}).get("uri"),
                      phys.get("region", {}).get("startLine"))
            if fp not in seen:
                seen.add(fp)
                unique.append(result)
        run["results"] = unique
    return sarif

Common Pitfalls

Path Normalization

Different tools report paths differently (absolute, relative, URI-encoded):

from urllib.parse import unquote
from pathlib import Path

def normalize_path(uri: str, base_path: str = "") -> str:
    if uri.startswith("file://"):
        uri = uri[7:]
    uri = unquote(uri)
    if not Path(uri).is_absolute() and base_path:
        uri = str(Path(base_path) / uri)
    return str(Path(uri))

Fingerprint Mismatch Across Runs

Fingerprints may differ when file paths, tool versions, or code formatting change between runs. Use a content-based fingerprint as fallback:

import hashlib

def compute_stable_fingerprint(result: dict, file_content: str = None) -> str:
    components = [result.get("ruleId", ""), result.get("message", {}).get("text", "")[:100]]
    if file_content and result.get("locations"):
        region = result["locations"][0].get("physicalLocation", {}).get("region", {})
        if region.get("startLine"):
            lines = file_content.split("\n")
            idx = region["startLine"] - 1
            if 0 <= idx < len(lines):
                components.append(lines[idx].strip())
    return hashlib.sha256("".join(components).encode()).hexdigest()[:16]

Missing or Incomplete Data

SARIF allows many optional fields. Use defensive access:

def safe_get_location(result: dict) -> tuple[str, int]:
    try:
        loc = result.get("locations", [{}])[0]
        phys = loc.get("physicalLocation", {})
        return (phys.get("artifactLocation", {}).get("uri", "unknown"),
                phys.get("region", {}).get("startLine", 0))
    except (IndexError, KeyError, TypeError):
        return "unknown", 0

Large File Performance

For 100MB+ SARIF files, stream instead of loading entirely:

import ijson  # pip install ijson

def stream_results(sarif_path: str):
    with open(sarif_path, "rb") as f:
        for result in ijson.items(f, "runs.item.results.item"):
            yield result

Schema Validation

Validate structure before processing:

# ajv-cli
ajv validate -s sarif-schema-2.1.0.json -d results.sarif

# Python
pip install jsonschema

from jsonschema import validate, ValidationError
import json

def validate_sarif(sarif_path: str, schema_path: str) -> bool:
    with open(sarif_path) as f:
        sarif = json.load(f)
    with open(schema_path) as f:
        schema = json.load(f)
    try:
        validate(sarif, schema)
        return True
    except ValidationError as e:
        print(f"Validation error: {e.message}")
        return False

CI/CD Integration

GitHub Actions

- name: Upload SARIF
  uses: github/codeql-action/upload-sarif@v3
  with:
    sarif_file: results.sarif

- name: Check for high severity
  run: |
    HIGH_COUNT=$(jq '[.runs[].results[] | select(.level == "error")] | length' results.sarif)
    if [ "$HIGH_COUNT" -gt 0 ]; then
      echo "Found $HIGH_COUNT high severity issues"
      exit 1
    fi

Regression Detection

from sarif import loader

def check_for_regressions(baseline: str, current: str) -> int:
    baseline_fps = {get_fingerprint(r) for r in loader.load_sarif_file(baseline).get_results()}
    new_issues = [r for r in loader.load_sarif_file(current).get_results()
                  if get_fingerprint(r) not in baseline_fps]
    return len(new_issues)

Key Principles

1. Validate first — check SARIF structure before processing
2. Handle optionals — many fields are optional; use defensive access
3. Normalize paths — tools report paths differently; normalize early
4. Fingerprint wisely — combine multiple strategies for stable deduplication
5. Stream large files — use ijson for 100MB+ files
6. Aggregate thoughtfully — preserve tool metadata when combining files

Resources

• jq query templates — 40+ queries for common SARIF operations
• Python utilities — normalize, fingerprint, deduplicate helpers
• OASIS SARIF 2.1.0 Spec
• Microsoft SARIF Tutorials
• sarif-tools (Python)
• GitHub SARIF Support