Blue Green Comparator: Public Worked Example

Offline, read-only parity comparison of two complete redacted environment snapshots. It does not switch traffic or deploy.

This walkthrough uses the tool's public README and checked-in example files. Run the command from a repository checkout with Node.js 22+.

Run the checked-in example

node bin/blue-green-comparator.mjs --root examples/pass --policy policy.json --blue blue.json --green green.json
node bin/blue-green-comparator.mjs --root examples/fail --policy policy.json --blue blue.json --green green.json
npm run check

Read the result

The CLI emits one JSON report: exit 0=pass, 1=fail, 2=incomplete or invalid configuration. Invalid options, root, or policy leave stdout empty. Unreadable or invalid blue/green inputs produce an incomplete report. Input paths are resolved by realpath beneath --root; strict UTF-8 and duplicate decoded JSON keys are enforced. It writes no files.

Scope

Policy ≤65,536 bytes; each snapshot ≤524,288 bytes; ≤1,000 dependencies and ≤1,000 migrations per side; JSON depth ≤16; evaluation deadline 5,000 ms using an injectable monotonic clock. N is accepted and N+1 rejected for each bound. Findings are ordered by UTF-16 code-unit order. This is structural parity of supplied redacted exports, not a live infrastructure audit or proof of runtime equivalence.