Catch schema migration risks
before they merge.

name: Schema Diff

on:
  pull_request:
    paths:
      - 'db/schema.sql'
      - 'migrations/*.sql'
      - '**/*.sql'

jobs:
  schema-diff:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Run SchemaLens Diff
        id: diff
        run: |
          git show origin/\${{ github.base_ref }}:db/schema.sql > /tmp/schema_base.sql 2>/dev/null || echo "-- No base schema" > /tmp/schema_base.sql
          node ci/schemalens-diff.js /tmp/schema_base.sql db/schema.sql --dialect=postgres --format=markdown --output=/tmp/report.md
          echo "report<> \$GITHUB_OUTPUT
          cat /tmp/report.md >> \$GITHUB_OUTPUT
          echo "EOF" >> \$GITHUB_OUTPUT

      - name: Comment PR
        uses: actions/github-script@v7
        with:
          script: |
            const report = `\${{ steps.diff.outputs.report }}`;
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: '## SchemaLens Diff Report\n\n' + report
            });Copy

schema_diff:
  stage: test
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      changes:
        - db/schema.sql
        - migrations/*.sql
  image: node:20-alpine
  script:
    - git fetch origin $CI_MERGE_REQUEST_TARGET_BRANCH_NAME
    - git show origin/$CI_MERGE_REQUEST_TARGET_BRANCH_NAME:db/schema.sql > /tmp/schema_base.sql 2>/dev/null || echo "-- No base schema" > /tmp/schema_base.sql
    - node ci/schemalens-diff.js /tmp/schema_base.sql db/schema.sql --dialect=postgres --format=markdown --output=schema_diff_report.md
  artifacts:
    paths:
      - schema_diff_report.md
    expire_in: 1 weekCopy

// Jenkinsfile
pipeline {
  agent any
  environment {
    SCHEMA_PATH = 'db/schema.sql'
    DIALECT = 'postgres'
    FAIL_ON_BREAKING = 'true'
    SKIP_NO_SQL_CHANGE = 'true'
  }
  stages {
    stage('Schema Diff') {
      steps {
        sh 'curl -s https://schemalens.tech/ci/jenkins-diff.sh | bash'
      }
    }
  }
  post {
    always {
      archiveArtifacts artifacts: 'schema_diff_report.md'
    }
  }
}Copy

# .circleci/config.yml
version: 2.1
jobs:
  schema-diff:
    docker:
      - image: cimg/node:20.0
    steps:
      - checkout
      - run:
          name: Schema Diff
          command: curl -s https://schemalens.tech/ci/circleci-diff.sh | bash
      - store_artifacts:
          path: schema_diff_report.mdCopy

# Download the CLI
curl -O https://schemalens.tech/ci/schemalens-diff.js

# Basic usage
node ci/schemalens-diff.js old_schema.sql new_schema.sql

# With options
node ci/schemalens-diff.js old_schema.sql new_schema.sql \
  --dialect=postgres \
  --format=markdown \
  --output=diff_report.md

# JSON output for programmatic gates
node ci/schemalens-diff.js old_schema.sql new_schema.sql \
  --dialect=mysql \
  --format=json \
  --output=diff.jsonCopy