feature-flags

Feature Flag System

Action: $ARGUMENTS (default: init)

Parse $ARGUMENTS:

• init — Generate the complete feature flag system (DB schema, service, API, admin UI)
• create <flag-name> [--description "..."] [--rollout 0-100] — Create a new feature flag
• list — Show all flags with status, rollout %, and usage stats
• toggle <flag-name> [--env staging|production] [--on|--off] — Toggle a flag
• cleanup — Find and remove stale/fully-rolled-out flags from code
• No argument = init

---

Step 0: Detect Project Context

echo "=== Project Type ==="
ls package.json pyproject.toml build.gradle.kts pom.xml 2>/dev/null

echo "=== Backend Language ==="
if [ -f "pyproject.toml" ] || [ -f "requirements.txt" ]; then
  echo "Python/FastAPI detected"
elif [ -f "package.json" ] && grep -q "nestjs" package.json 2>/dev/null; then
  echo "NestJS detected"
elif [ -f "build.gradle.kts" ] || [ -f "pom.xml" ]; then
  echo "Spring Boot detected"
fi

echo "=== Existing Feature Flags ==="
grep -rn "feature.flag\|feature_flag\|FeatureFlag\|FEATURE_" --include="*.py" --include="*.ts" --include="*.java" . 2>/dev/null | grep -v node_modules | head -20

echo "=== Database ==="
grep -rn "mysql\|DATABASE_URL" .env* 2>/dev/null | head -5
grep -rn "redis\|REDIS" .env* 2>/dev/null | head -5

---

Step 1: Database Schema (Action: init)

MySQL Migration

Generate the feature flags table migration.

Python (Alembic):

"""create feature flags tables

Revision ID: xxxx
"""
from alembic import op
import sqlalchemy as sa
from sqlalchemy.dialects.mysql import JSON

def upgrade() -> None:
    op.create_table(
        'feature_flags',
        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
        sa.Column('name', sa.String(100), nullable=False, unique=True, index=True),
        sa.Column('description', sa.Text(), nullable=True),
        sa.Column('enabled', sa.Boolean(), default=False, nullable=False),
        sa.Column('rollout_percentage', sa.Integer(), default=0, nullable=False),
        sa.Column('conditions', JSON, nullable=True),  # {"roles": ["admin"], "user_ids": [1,2,3], "regions": ["IN"]}
        sa.Column('kill_switch', sa.Boolean(), default=False, nullable=False),  # True = force OFF regardless
        sa.Column('stale_after', sa.DateTime(), nullable=True),  # When this flag should be reviewed
        sa.Column('created_by', sa.String(100), nullable=True),
        sa.Column('created_at', sa.DateTime(), server_default=sa.func.now(), nullable=False),
        sa.Column('updated_at', sa.DateTime(), server_default=sa.func.now(), onupdate=sa.func.now(), nullable=False),
        sa.PrimaryKeyConstraint('id'),
    )

    op.create_table(
        'feature_flag_overrides',
        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
        sa.Column('flag_id', sa.Integer(), sa.ForeignKey('feature_flags.id', ondelete='CASCADE'), nullable=False),
        sa.Column('user_id', sa.Integer(), nullable=True),
        sa.Column('role', sa.String(50), nullable=True),
        sa.Column('enabled', sa.Boolean(), nullable=False),
        sa.Column('created_at', sa.DateTime(), server_default=sa.func.now(), nullable=False),
        sa.PrimaryKeyConstraint('id'),
        sa.UniqueConstraint('flag_id', 'user_id', name='uq_flag_user'),
    )

    op.create_table(
        'feature_flag_audit_log',
        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
        sa.Column('flag_id', sa.Integer(), sa.ForeignKey('feature_flags.id', ondelete='CASCADE'), nullable=False),
        sa.Column('action', sa.String(50), nullable=False),  # created, enabled, disabled, rollout_changed, deleted
        sa.Column('old_value', sa.Text(), nullable=True),
        sa.Column('new_value', sa.Text(), nullable=True),
        sa.Column('changed_by', sa.String(100), nullable=True),
        sa.Column('changed_at', sa.DateTime(), server_default=sa.func.now(), nullable=False),
        sa.PrimaryKeyConstraint('id'),
    )

def downgrade() -> None:
    op.drop_table('feature_flag_audit_log')
    op.drop_table('feature_flag_overrides')
    op.drop_table('feature_flags')