Drone

**Essential Configuration:**

1. **Server Configuration (.env file):**
```env
# Core Settings
DRONE_SERVER_HOST=drone.example.com
DRONE_SERVER_PROTO=https
DRONE_RPC_SECRET=supersecretkey

# Database
DRONE_DATABASE_DRIVER=postgres
DRONE_DATABASE_DATASOURCE=postgres://user:pass@localhost:5432/drone?sslmode=disable

# VCS Integration (GitHub example)
DRONE_GITHUB_CLIENT_ID=github_oauth_app_id
DRONE_GITHUB_CLIENT_SECRET=github_oauth_secret

# User Management
DRONE_USER_CREATE=username:admin,admin:true
DRONE_USER_FILTER=organization_name # Only allow specific org
```

2. **Pipeline Configuration (.drone.yml) - Basic:**
```yaml
kind: pipeline
type: docker
name: build-test-deploy

steps:
- name: install
image: node:18
commands:
- npm ci

- name: test
image: node:18
commands:
- npm test
- npm run lint

- name: build
image: node:18
commands:
- npm run build

- name: deploy
image: plugins/ssh
settings:
host: production.example.com
username: deploy
key:
from_secret: ssh_private_key
script:
- cd /var/www/app
- git pull
- npm install
- pm2 restart app
when:
branch:
- main
```

3. **Matrix Builds (Multiple Versions):**
```yaml
kind: pipeline
type: docker
name: matrix-test

steps:
- name: test
image: python:${PYTHON_VERSION}
commands:
- pip install -r requirements.txt
- pytest

matrix:
PYTHON_VERSION:
- "3.8"
- "3.9"
- "3.10"
- "3.11"
```

4. **Docker Build and Push:**
```yaml
kind: pipeline
type: docker
name: docker-build

steps:
- name: build-and-push
image: plugins/docker
settings:
repo: username/myapp
tags:
- latest
- ${DRONE_COMMIT_SHA:0:8}
username:
from_secret: docker_username
password:
from_secret: docker_password
dockerfile: Dockerfile
context: .
```

5. **Kubernetes Deployment:**
```yaml
kind: pipeline
type: docker
name: k8s-deploy

steps:
- name: deploy-to-k8s
image: sinlead/drone-kubectl
settings:
kubernetes_server: https://k8s.example.com
kubernetes_token:
from_secret: k8s_token
kubernetes_cert:
from_secret: k8s_cert
commands:
- kubectl set image deployment/myapp myapp=username/myapp:${DRONE_COMMIT_SHA}
- kubectl rollout status deployment/myapp
when:
branch:
- main
```

6. **Conditional Execution:**
```yaml
kind: pipeline
type: docker
name: conditional-deploy

steps:
- name: deploy-staging
image: plugins/ssh
commands:
- deploy to staging
when:
branch:
- develop

- name: deploy-production
image: plugins/ssh
commands:
- deploy to production
when:
branch:
- main
event:
- push
- tag

- name: deploy-on-tag
image: plugins/ssh
commands:
- deploy release
when:
event:
- tag
ref:
- refs/tags/v*
```

7. **Services (Database, Redis for Testing):**
```yaml
kind: pipeline
type: docker
name: integration-tests

services:
- name: postgres
image: postgres:14
environment:
POSTGRES_USER: testuser
POSTGRES_PASSWORD: testpass
POSTGRES_DB: testdb

- name: redis
image: redis:7

steps:
- name: test
image: python:3.11
environment:
DATABASE_URL: postgres://testuser:testpass@postgres:5432/testdb
REDIS_URL: redis://redis:6379
commands:
- pip install -r requirements.txt
- pytest tests/integration/
```

8. **Secrets Management:**
```yaml
# Via CLI
drone secret add --repository user/repo --name aws_access_key --data value
drone secret add --repository user/repo --name aws_secret_key --data value

# In pipeline
kind: pipeline
type: docker
name: default

steps:
- name: deploy
image: plugins/s3
settings:
access_key:
from_secret: aws_access_key
secret_key:
from_secret: aws_secret_key
bucket: my-bucket
source: dist/**/*
```

9. **Caching Dependencies:**
```yaml
kind: pipeline
type: docker
name: cached-build

steps:
- name: restore-cache
image: drillster/drone-volume-cache
volumes:
- name: cache
path: /cache
settings:
restore: true
mount:
- ./node_modules

- name: build
image: node:18
commands:
- npm ci
- npm run build

- name: rebuild-cache
image: drillster/drone-volume-cache
volumes:
- name: cache
path: /cache
settings:
rebuild: true
mount:
- ./node_modules

volumes:
- name: cache
host:
path: /var/lib/drone/cache
```

10. **Notifications (Slack, Email):**
```yaml
kind: pipeline
type: docker
name: notify

steps:
- name: build
image: node:18
commands:
- npm run build

- name: slack
image: plugins/slack
settings:
webhook:
from_secret: slack_webhook
channel: deployments
template: >
{{#success build.status}}
✅ Build #{{build.number}} succeeded. Branch: {{build.branch}}
{{else}}
❌ Build #{{build.number}} failed. Branch: {{build.branch}}
{{/success}}
when:
status:
- success
- failure
```

**Best Practices:**
- Store sensitive data in secrets, never in .drone.yml
- Use specific image tags (node:18) instead of latest
- Enable caching for faster builds (node_modules, pip packages)
- Use services for integration testing with real databases
- Implement matrix builds to test multiple versions
- Use conditional execution to prevent unnecessary deployments
- Set up proper branch protection (deploy only from main/master)
- Monitor build performance and optimize slow steps