### **Top 100 Flask Developer Interview Questions & Answers (Part 4: Questions 301–400)** --- #### **301. How do you deploy Flask on AWS Elastic Beanstalk with Docker?** **Answer:** 1. Create `Dockerfile` (see Q145) 2. Add `elasticbeanstalk` config: ```yaml # .ebextensions/flask.config option_settings: aws:elasticbeanstalk:container:docker:environment: FLASK_ENV: production aws:elasticbeanstalk:application:environment: SECRET_KEY: <%= ENV['SECRET_KEY'] %> ``` 3. Deploy: `eb deploy --staged` --- #### **302. How do you configure AWS RDS IAM authentication for Flask?** **Answer:** ```python import boto3 from sqlalchemy.engine import URL client = boto3.client('rds') token = client.generate_db_auth_token( DBHostname=os.getenv('RDS_HOST'), Port=5432, DBUsername='iam_user', Region='us-east-1' ) app.config['SQLALCHEMY_DATABASE_URI'] = URL.create( "postgresql+psycopg2", username="iam_user", password=token, host=os.getenv('RDS_HOST'), database="mydb" ) ``` --- #### **303. How do you implement Cloudflare rate limiting for Flask apps?** **Answer:** Configure in Cloudflare dashboard: 1. **Rules > Rate limiting**: - Path: `/api/*` - Threshold: `100 requests/5 minutes` - Action: `Block` 2. Verify headers in Flask: ```python @app.before_request def check_cloudflare(): if request.headers.get('CF-RAY'): g.cloudflare = True ``` --- #### **304. How do you set up AWS X-Ray tracing for Flask?** **Answer:** ```python from aws_xray_sdk.core import xray_recorder from aws_xray_sdk.ext.flask.middleware import XRayMiddleware xray_recorder.configure(service='Flask App') XRayMiddleware(app, xray_recorder) # Add plugins for AWS services from aws_xray_sdk.ext.dbapi import XRayTracedConn conn = XRayTracedConn(psycopg2.connect, 'postgresql://...') # Manual subsegments with xray_recorder.in_subsegment('external_call'): requests.get('https://api.example.com') ``` --- #### **305. How do you handle "cold starts" in AWS Lambda Flask deployments?** **Answer:** Mitigation strategies: 1. **Provisioned concurrency**: Keep warm instances 2. **Optimize package size**: Remove unused dependencies 3. **Lazy imports**: ```python def lambda_handler(event, context): from app import create_app # Import inside handler return Mangum(create_app())(event, context) ``` 4. **Keep-alive pings**: Scheduled CloudWatch Events --- #### **306. How do you configure GCP Cloud SQL Auth Proxy for Flask?** **Answer:** 1. Start proxy: ```bash cloud_sql_proxy -instances=my-project:us-central1:my-db=tcp:5432 ``` 2. Configure Flask: ```python app.config['SQLALCHEMY_DATABASE_URI'] = ( f"postgresql+pg8000://user:password@127.0.0.1:5432/mydb" ) ``` *Alternative:* Use [Cloud SQL Python Connector](https://pypi.org/project/cloud-sql-python-connector/) --- #### **307. How do you implement Azure Active Directory auth in Flask?** **Answer:** Use `flask-oidc`: ```python oidc = OpenIDConnect(app) @app.route('/login') @oidc.require_login def login(): return redirect(url_for('dashboard')) @app.route('/dashboard') @oidc.accept_token(True) def dashboard(): return f"Hello {g.oidc_token_info['sub']}" ``` *Configure:* ```ini OIDC_CLIENT_SECRETS = { "web": { "client_id": "AZURE_CLIENT_ID", "client_secret": "AZURE_CLIENT_SECRET", "auth_uri": "https://login.microsoftonline.com/common/oauth2/v2.0/authorize", "token_uri": "https://login.microsoftonline.com/common/oauth2/v2.0/token" } } ``` --- #### **308. How do you set up Google Cloud Trace for Flask?** **Answer:** ```python from opentelemetry import trace from opentelemetry.exporter.cloud_trace import CloudTraceSpanExporter from opentelemetry.instrumentation.flask import FlaskInstrumentor from opentelemetry.propagate import set_global_textmap from opentelemetry.propagators.cloud_trace_propagator import ( CloudTraceFormatPropagator ) set_global_textmap(CloudTraceFormatPropagator()) FlaskInstrumentor().instrument_app(app) trace.get_tracer_provider().add_span_processor( CloudTraceSpanExporter() ) ``` --- #### **309. How do you configure AWS ALB sticky sessions for Flask?** **Answer:** 1. Enable **stickiness** in ALB target group: - Stickiness type: `app_cookie` - Cookie name: `session_id` 2. Configure Flask to use cookie-based sessions: ```python app.config.update( SESSION_COOKIE_NAME='session_id', SESSION_COOKIE_SECURE=True ) ``` --- #### **310. How do you implement "canary deployments" for Flask apps on Kubernetes?** **Answer:** 1. Deploy new version with `canary` label: ```yaml apiVersion: apps/v1 kind: Deployment metadata: name: flask-app-canary spec: replicas: 2 selector: matchLabels: app: flask-app version: canary ``` 2. Configure Istio route rules: ```yaml apiVersion: networking.istio.io/v1alpha3 kind: VirtualService spec: http: - route: - destination: host: flask-app subset: v1 weight: 90 - destination: host: flask-app subset: canary weight: 10 ``` --- #### **311. How do you configure Prometheus metrics for Flask?** **Answer:** Use `prometheus_flask_exporter`: ```python from prometheus_flask_exporter import PrometheusMetrics metrics = PrometheusMetrics(app) metrics.info('app_info', 'Application info', version='1.0.0') @metrics.do_not_track() @metrics.summary('request_latency_seconds', 'Request latency') @app.route('/data') def data(): # ... ``` *Scrape via:* ```yaml # prometheus.yml scrape_configs: - job_name: 'flask' static_configs: - targets: ['flask-app:5000'] ``` --- #### **312. How do you track custom metrics in AWS CloudWatch?** **Answer:** ```python import boto3 from flask import g cloudwatch = boto3.client('cloudwatch') @app.before_request def start_timer(): g.start = time.time() @app.after_request def log_request(response): duration = time.time() - g.start cloudwatch.put_metric_data( Namespace='FlaskApp', MetricData=[{ 'MetricName': 'RequestDuration', 'Value': duration, 'Unit': 'Seconds', 'Dimensions': [{'Name': 'Endpoint', 'Value': request.path}] }] ) return response ``` --- #### **313. How do you implement "blue-green deployments" on Heroku?** **Answer:** 1. Deploy to staging app: `git push heroku-staging main` 2. Run migrations: `heroku run flask db upgrade --app staging-app` 3. Swap URLs: ```bash heroku pipelines:promote --app production-pipeline --to production ``` 4. Verify then destroy old release --- #### **314. How do you configure Datadog APM for Flask?** **Answer:** ```python from ddtrace import tracer, patch_all patch_all() @app.route('/process') def process(): with tracer.trace("custom_operation"): # ... return "Done" ``` *Environment:* ```bash DD_SERVICE=flask-app DD_ENV=production DD_TRACE_AGENT_URL=http://datadog:8126 ``` --- #### **315. How do you set up GitHub Actions CI/CD for Flask?** **Answer:** `.github/workflows/ci.yml`: ```yaml name: Flask CI/CD on: push: branches: [main] jobs: deploy: runs-on: ubuntu-latest steps: - uses: actions/checkout@v3 - name: Set up Python uses: actions/setup-python@v4 with: python-version: '3.10' - name: Install dependencies run: | python -m pip install --upgrade pip pip install -r requirements.txt - name: Run tests run: pytest - name: Deploy to AWS if: github.ref == 'refs/heads/main' env: AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }} run: eb deploy production ``` --- #### **316. How do you implement "feature branch deployments" on Vercel?** **Answer:** For Flask APIs (via serverless functions): 1. Structure project: ``` /api /__vercel output static config.json hello.py ``` 2. `hello.py`: ```python def handler(request): return {"body": "Hello from feature branch!", "statusCode": 200} ``` 3. Configure `vercel.json`: ```json { "builds": [ { "src": "api/hello.py", "use": "@vercel/python" } ] } ``` --- #### **317. How do you configure log rotation for Gunicorn?** **Answer:** ```bash gunicorn app:app \ --access-logfile - \ --error-logfile gunicorn.log \ --log-config <(cat <<EOF [loggers] keys = root [handlers] keys = file [formatters] keys = generic [logger_root] level = INFO handlers = file [handler_file] class = handlers.RotatingFileHandler args = ('gunicorn.log', 'a', 100*1024*1024, 10) formatter = generic [formatter_generic] format = %(asctime)s [%(process)d] [%(levelname)s] %(message)s EOF ) ``` --- #### **318. How do you implement "circuit breakers" for external APIs in production?** **Answer:** With `pybreaker` + statsd: ```python import statsd from pybreaker import CircuitBreaker breaker = CircuitBreaker( fail_max=5, reset_timeout=60, exclude=[requests.HTTPError] ) @breaker def call_external(): statsd.increment("external_api.calls") return requests.get("https://api.example.com") # Track state changes breaker.state_change += lambda old, new: statsd.gauge( "external_api.circuit_breaker", 1 if new.name == "open" else 0 ) ``` --- #### **319. How do you set up Grafana alerts for Flask errors?** **Answer:** 1. Push logs to Loki: ```python from grafana_loki import LokiHandler handler = LokiHandler(url="http://loki:3100/loki/api/v1/push", tags={"app": "flask"}) app.logger.addHandler(handler) ``` 2. Create alert rule in Grafana: ``` count_over_time( {app="flask"} |~ "ERROR" [5m] ) > 10 ``` --- #### **320. How do you configure Kubernetes liveness probes for Flask?** **Answer:** ```yaml livenessProbe: httpGet: path: /health port: 5000 initialDelaySeconds: 15 periodSeconds: 20 failureThreshold: 3 # In Flask: @app.route('/health') def health(): try: db.engine.execute('SELECT 1') return 'OK', 200 except Exception: return 'DB connection failed', 500 ``` --- #### **321. How do you implement "distributed tracing" across Flask and Celery?** **Answer:** Propagate trace context: ```python # In Flask from opentelemetry.propagate import inject @app.route('/task') def task(): headers = {} inject(headers) # Inject trace context process_task.apply_async(kwargs={'headers': headers}) # In Celery task from opentelemetry.propagate import extract from opentelemetry.trace import set_span_in_context @celery.task def process_task(headers): ctx = extract(headers) tracer = trace.get_tracer(__name__) with tracer.start_as_current_span("process_task", context=ctx): # Task logic ``` --- #### **322. How do you configure AWS CloudFront for Flask static files?** **Answer:** 1. Set S3 bucket as origin 2. Configure cache behaviors: - Path pattern: `/static/*` - TTL: `31536000` (1 year) - Query string: `Forward all, cache based on all` 3. In Flask: ```python app.config['STATIC_URL_PATH'] = os.getenv('CLOUDFRONT_URL', '/static') ``` --- #### **323. How do you implement "real-time logs" with Papertrail?** **Answer:** ```python import logging from logging.handlers import SysLogHandler handler = SysLogHandler(address=('logsN.papertrailapp.com', PORT)) formatter = logging.Formatter('flask-app: %(message)s') handler.setFormatter(formatter) app.logger.addHandler(handler) app.logger.setLevel(logging.INFO) ``` --- #### **324. How do you set up "golden signals" monitoring for Flask?** **Answer:** Track: 1. **Traffic**: `requests_total` (counter) 2. **Errors**: `request_errors_total` (counter) 3. **Latency**: `request_duration_seconds` (histogram) 4. **Saturation**: `worker_utilization` (gauge) *Implementation:* ```python from prometheus_client import Counter, Histogram REQUESTS = Counter('flask_http_requests_total', 'Total HTTP requests', ['method', 'endpoint']) LATENCY = Histogram('flask_http_request_duration_seconds', 'Request duration', ['endpoint']) @app.before_request def before_request(): g.start = time.time() @app.after_request def after_request(response): latency = time.time() - g.start LATENCY.labels(request.path).observe(latency) REQUESTS.labels(request.method, request.path).inc() return response ``` --- #### **325. How do you configure "zero-downtime" deployments on Kubernetes?** **Answer:** ```yaml apiVersion: apps/v1 kind: Deployment spec: replicas: 3 strategy: type: RollingUpdate rollingUpdate: maxSurge: 25% maxUnavailable: 0 # Critical for zero downtime template: spec: containers: - name: flask readinessProbe: httpGet: path: /ready port: 5000 initialDelaySeconds: 5 periodSeconds: 5 ``` --- #### **326. How do you implement "chaos engineering" tests for Flask?** **Answer:** Use Chaos Toolkit: ```yaml # experiment.yml version: "1.0" title: "Flask Resilience Test" method: - type: action name: "inject-latency" provider: type: process path: "tc" arguments: "qdisc add dev eth0 root netem delay 1000ms" - type: probe name: "check-availability" provider: type: http url: "http://flask-app:5000/health" timeout: 30 - type: action name: "restore-network" provider: type: process path: "tc" arguments: "qdisc del dev eth0 root netem" ``` --- #### **327. How do you configure "autoscaling" for Flask on GKE?** **Answer:** ```yaml apiVersion: autoscaling/v2 kind: HorizontalPodAutoscaler metadata: name: flask-hpa spec: scaleTargetRef: apiVersion: apps/v1 kind: Deployment name: flask-app minReplicas: 2 maxReplicas: 10 metrics: - type: Resource resource: name: cpu target: type: Utilization averageUtilization: 70 - type: Pods pods: metric: name: flask_http_request_duration_seconds target: type: AverageValue averageValue: 100m # 100ms latency ``` --- #### **328. How do you implement "log-based metrics" in Google Cloud?** **Answer:** 1. Create log-based metric in Cloud Logging: - Name: `flask_errors` - Filter: `resource.type="gae_app" jsonPayload.level="ERROR"` 2. Alert when: - `Metric: flask_errors` - `Condition: > 10 for 5 minutes` --- #### **329. How do you configure "service mesh" for Flask microservices?** **Answer:** Istio sidecar configuration: ```yaml apiVersion: networking.istio.io/v1alpha3 kind: VirtualService spec: hosts: - flask-service http: - route: - destination: host: flask-service subset: v1 weight: 90 - destination: host: flask-service subset: v2 weight: 10 retries: attempts: 3 perTryTimeout: 2s ``` --- #### **330. How do you implement "database connection pooling" for serverless Flask?** **Answer:** Use **RDS Proxy** for AWS Lambda: ```python # In Lambda handler def lambda_handler(event, context): conn = pymysql.connect( host=os.getenv('RDS_PROXY_ENDPOINT'), user='lambda_user', password=os.getenv('DB_PASSWORD'), database='mydb', cursorclass=pymysql.cursors.DictCursor ) # Execute query... ``` *Configure RDS Proxy with IAM authentication* --- #### **331. How do you set up "infrastructure as code" for Flask deployments?** **Answer:** Terraform example: ```hcl # main.tf module "flask_app" { source = "terraform-aws-modules/elastic-beanstalk-environment/aws" application_name = "flask-app" environment_name = "production" solution_stack_name = "64bit Amazon Linux 2 v5.6.4 running Python 3.8" setting = [ { namespace = "aws:autoscaling:asg" name = "MinSize" value = "2" }, { namespace = "aws:elasticbeanstalk:application:environment" name = "SECRET_KEY" value = var.secret_key } ] } ``` --- #### **332. How do you implement "canary analysis" with Flagger?** **Answer:** ```yaml apiVersion: flagger.app/v1beta1 kind: Canary spec: analysis: interval: 1m threshold: 10 maxWeight: 50 stepWeight: 5 metrics: - name: error-rate thresholdRange: max: 0.01 interval: 1m - name: latency thresholdRange: max: 500 interval: 1m ``` --- #### **333. How do you configure "distributed tracing" with Jaeger?** **Answer:** ```python from jaeger_client import Config def init_tracer(): config = Config( config={ 'sampler': {'type': 'const', 'param': 1}, 'logging': True, }, service_name='flask-app' ) return config.initialize_tracer() tracer = init_tracer() @app.route('/traced') def traced(): with tracer.start_span('web_request') as span: span.set_tag('http.url', request.url) # ... ``` --- #### **334. How do you implement "real-time performance monitoring" with Sentry?** **Answer:** ```python import sentry_sdk from sentry_sdk.integrations.flask import FlaskIntegration sentry_sdk.init( dsn="https://example@sentry.io/0", integrations=[FlaskIntegration()], traces_sample_rate=0.1 # 10% of transactions ) @app.route('/transaction') def transaction(): with sentry_sdk.start_transaction(op="request", name="Custom Transaction"): # ... ``` --- #### **335. How do you configure "log aggregation" with ELK Stack?** **Answer:** 1. Filebeat config: ```yaml filebeat.inputs: - type: filestream paths: - /var/log/gunicorn.log output.logstash: hosts: ["logstash:5044"] ``` 2. Logstash pipeline: ``` filter { grok { match => { "message" => "%{TIMESTAMP_ISO8601:timestamp} \[%{NUMBER:pid}\] %{LOGLEVEL:level} %{GREEDYDATA:msg}" } } } ``` --- #### **336. How do you implement "chaos monkey" for Flask?** **Answer:** Randomly kill workers: ```python import os import random @app.before_request def chaos_monkey(): if random.random() < 0.01: # 1% chance os._exit(1) # Simulate crash ``` *Better:* Use controlled chaos via service mesh (Istio fault injection) --- #### **337. How do you configure "multi-region failover" on AWS?** **Answer:** 1. Route53 latency-based routing 2. Global Application Load Balancer 3. Aurora Global Database (primary → secondary replication) 4. Health checks: ```python @app.route('/health') def health(): if not db.is_primary(): return "Read-only replica", 503 return "OK", 200 ``` --- #### **338. How do you implement "real-time anomaly detection" for Flask metrics?** **Answer:** Use Prometheus + ML: 1. Export metrics to Prometheus 2. Train model with PyOD: ```python from pyod.models.knn import KNN anomaly_detector = KNN() anomaly_detector.fit(latency_data) # In alert manager if anomaly_detector.predict(new_latency) == 1: trigger_alert() ``` --- #### **339. How do you configure "infrastructure monitoring" with Datadog?** **Answer:** 1. Install Datadog agent: ```yaml # datadog-agent.yaml apiVersion: apps/v1 kind: DaemonSet spec: template: spec: containers: - name: agent image: datadog/agent:latest env: - name: DD_API_KEY value: "<YOUR_API_KEY>" ``` 2. Flask integration auto-discovers via service tags --- #### **340. How do you implement "distributed configuration" with Consul?** **Answer:** ```python import consul c = consul.Consul() index, config = c.kv.get("flask/config", recurse=True) app.config.update( {item['Key'].split('/')[-1]: item['Value'] for item in config} ) # Watch for changes def watch_config(): index = None while True: index, data = c.kv.get("flask/config", index=index, recurse=True) if data: app.config.update(process_config(data)) Thread(target=watch_config).start() ``` --- #### **341. How do you configure "service discovery" for Flask microservices?** **Answer:** Use Consul DNS: ```python import dns.resolver def get_service_url(service_name): answers = dns.resolver.resolve(f'{service_name}.service.consul', 'A') ip = random.choice(answers).to_text() return f"http://{ip}:5000" ``` *Alternative:* Use `requests` with Consul template: ```bash consul-template -template "template.ctmpl:service_url" -once ``` --- #### **342. How do you implement "blueprint-level metrics" in Prometheus?** **Answer:** ```python from prometheus_client import Counter def create_blueprint(name): bp = Blueprint(name, __name__) counter = Counter(f'{name}_requests_total', 'Requests per blueprint') @bp.before_request def count_requests(): counter.inc() return bp # Usage admin_bp = create_blueprint('admin') ``` --- #### **343. How do you configure "encrypted secrets" with HashiCorp Vault?** **Answer:** ```python import hvac client = hvac.Client(url='http://vault:8200') client.auth.approle.login( role_id=os.environ['VAULT_ROLE_ID'], secret_id=os.environ['VAULT_SECRET_ID'] ) secret = client.secrets.kv.v2.read_secret_version( path='flask-secrets' )['data']['data'] app.config['SECRET_KEY'] = secret['secret_key'] ``` --- #### **344. How do you implement "real-time config reload" with etcd?** **Answer:** ```python import etcd3 client = etcd3.client() watch_id = None def watch_config(): global watch_id watch_id = client.add_watch_callback( 'flask/config', lambda events: update_config(events) ) def update_config(events): for event in events: if isinstance(event, etcd3.events.PutEvent): key = event.key.decode() value = event.value.decode() app.config[key] = value watch_config() ``` --- #### **345. How do you configure "distributed tracing" with Zipkin?** **Answer:** ```python from flask import request from py_zipkin.zipkin import zipkin_span, create_http_headers_for_new_span @app.before_request def trace_before(): headers = {k: v for k, v in request.headers if k.lower() in ('x-b3-traceid', 'x-b3-spanid', 'x-b3-parentspanid', 'x-b3-sampled')} g.zipkin_trace_id = headers.get('x-b3-traceid', create_zipkin_id()) @zipkin_span(service_name='flask-app', span_name='web_request') def traced_function(): # ... @app.route('/traced') def traced(): with traced_function(): # ... ``` --- #### **346. How do you implement "real-time error tracking" with Rollbar?** **Answer:** ```python import rollbar from rollbar.contrib.flask import Rollbar rollbar.init( os.getenv('ROLLBAR_ACCESS_TOKEN'), environment=os.getenv('FLASK_ENV', 'development') ) @app.before_first_request def init_rollbar(): Rollbar(app) @app.route('/error') def error(): raise Exception("Test error") ``` --- #### **347. How do you configure "infrastructure as code" with AWS CDK?** **Answer:** Python CDK example: ```python from aws_cdk import ( aws_ecs as ecs, aws_ecs_patterns as ecs_patterns ) class FlaskStack(cdk.Stack): def __init__(self, scope: cdk.Construct, id: str, **kwargs) -> None: super().__init__(scope, id, **kwargs) flask_service = ecs_patterns.ApplicationLoadBalancedFargateService( self, "FlaskFargateService", image=ecs.ContainerImage.from_registry("my-flask-app:latest"), memory_limit_mib=1024, cpu=512 ) flask_service.target_group.configure_health_check( path="/health" ) ``` --- #### **348. How do you implement "real-time log analysis" with Splunk?** **Answer:** 1. Configure Flask logging: ```python import splunk_hec_handler handler = splunk_hec_handler.SplunkHecHandler( host='splunk', port=8088, token=os.getenv('SPLUNK_TOKEN'), index='main' ) app.logger.addHandler(handler) ``` 2. Create Splunk alerts for error patterns --- #### **349. How do you configure "multi-cloud deployments" for Flask?** **Answer:** 1. Abstract cloud services: ```python class CloudStorage: def __init__(self, provider): if provider == 'aws': self.client = boto3.client('s3') elif provider == 'gcp': self.client = storage.Client() def upload(self, file): # Provider-specific logic ``` 2. Use feature flags to switch providers per environment --- #### **350. How do you implement "real-time capacity planning" for Flask?** **Answer:** Track metrics + predictive scaling: ```python from sklearn.linear_model import LinearRegression # Historical data: [timestamp, requests, cpu] model = LinearRegression().fit(X_train, y_train) def predict_load(minutes_ahead=10): future_time = time.time() + minutes_ahead * 60 predicted_load = model.predict([[future_time]]) if predicted_load > current_capacity * 0.8: trigger_scale_up() ``` --- #### **351. How do you configure "serverless Flask" with AWS API Gateway?** **Answer:** Use `aws-wsgi` adapter: ```python # lambda_handler.py import aws_wsgi from app import app def lambda_handler(event, context): return aws_wsgi.response(app, event, context) ``` *Deploy with:* ```yaml # serverless.yml functions: app: handler: lambda_handler.lambda_handler events: - http: ANY / - http: 'ANY {proxy+}' ``` --- #### **352. How do you implement "real-time dependency tracking" for Flask?** **Answer:** ```python import requests from prometheus_client import Gauge DEPENDENCY_STATUS = Gauge('dependency_status', 'Dependency health', ['name']) def check_dependency(name, url): try: requests.get(url, timeout=2) DEPENDENCY_STATUS.labels(name).set(1) except: DEPENDENCY_STATUS.labels(name).set(0) # In background thread def monitor_dependencies(): while True: check_dependency('db', 'http://db:5432/health') check_dependency('redis', 'http://redis:6379/ping') time.sleep(10) ``` --- #### **353. How do you configure "infrastructure monitoring" with New Relic?** **Answer:** ```python import newrelic.agent newrelic.agent.initialize('newrelic.ini') application = newrelic.agent.WSGIApplicationWrapper(app) # In newrelic.ini [newrelic] license_key = YOUR_LICENSE_KEY app_name = Flask Application monitor_toolkit = true transaction_tracer.enabled = true ``` --- #### **354. How do you implement "real-time feature flag analytics" with StatsD?** **Answer:** ```python import statsd def is_feature_enabled(feature, user): enabled = feature_flags.is_enabled(feature, user) statsd.increment(f'feature.{feature}.{"enabled" if enabled else "disabled"}') return enabled ``` *Visualize in Grafana:* ``` sum(rate(feature_my_feature_enabled[5m])) / sum(rate(feature_my_feature_total[5m])) ``` --- #### **355. How do you configure "distributed tracing" with Honeycomb?** **Answer:** ```python from honeycomb.opentelemetry import configure_opentelemetry configure_opentelemetry( service_name="flask-app", write_key=os.getenv("HONEYCOMB_WRITEKEY"), dataset="flask-traces" ) # Auto-instruments Flask ``` --- #### **356. How do you implement "real-time canary analysis" with Prometheus?** **Answer:** ```python # In metrics CANARY_REQUESTS = Counter('canary_requests_total', 'Canary requests', ['version']) CANARY_ERRORS = Counter('canary_errors_total', 'Canary errors', ['version']) @app.route('/canary') def canary(): version = os.getenv('APP_VERSION') CANARY_REQUESTS.labels(version).inc() try: # Test logic except Exception as e: CANARY_ERRORS.labels(version).inc() raise ``` *Alert rule:* ``` rate(canary_errors_total{version="v2"}[5m]) / rate(canary_requests_total{version="v2"}[5m]) > 0.01 ``` --- #### **357. How do you configure "infrastructure as code" with Pulumi?** **Answer:** Python example: ```python import pulumi from pulumi_aws import ec2, ecs, elbv2 # Create VPC vpc = ec2.Vpc("flask-vpc", cidr_block="10.0.0.0/16") # Create ECS cluster cluster = ecs.Cluster("flask-cluster") # Create load balancer lb = elbv2.LoadBalancer("flask-lb", subnets=[vpc.public_subnet_ids[0], vpc.public_subnet_ids[1]], security_groups=[...] ) # Create service service = ecs.Service("flask-svc", cluster=cluster.arn, task_definition=task_definition.arn, desired_count=2, load_balancers=[{ "targetGroupArn": target_group.arn, "containerName": "flask", "containerPort": 5000 }] ) ``` --- #### **358. How do you implement "real-time anomaly detection" for error rates?** **Answer:** Use Prophet forecasting: ```python from fbprophet import Prophet def detect_anomalies(): # Get last 7 days of error data df = get_error_metrics() # Train model model = Prophet() model.fit(df) # Predict next hour future = model.make_future_dataframe(periods=6, freq='H') forecast = model.predict(future) # Check if current error rate > upper bound return current_error_rate > forecast['yhat_upper'].iloc[-1] ``` --- #### **359. How do you configure "infrastructure monitoring" with Sysdig?** **Answer:** 1. Install Sysdig agent: ```yaml apiVersion: apps/v1 kind: DaemonSet spec: template: spec: containers: - name: sysdig-agent image: sysdig/agent env: - name: ACCESS_KEY value: "<YOUR_ACCESS_KEY>" ``` 2. Create alert rules for Flask-specific metrics --- #### **360. How do you implement "real-time capacity forecasting" for database?** **Answer:** ```python import pandas as pd from statsmodels.tsa.arima.model import ARIMA def forecast_db_growth(): # Historical data: date, size_mb model = ARIMA(df['size_mb'], order=(1,1,0)) results = model.fit() forecast = results.forecast(steps=30) # 30 days if forecast.iloc[-1] > current_capacity * 0.9: trigger_resize() ``` --- #### **361. How do you configure "distributed tracing" with Lightstep?** **Answer:** ```python from opentelemetry import trace from opentelemetry.exporter.lightstep import LightstepOTLPSpanExporter from opentelemetry.sdk.trace import TracerProvider from opentelemetry.sdk.trace.export import BatchSpanProcessor trace.set_tracer_provider(TracerProvider()) trace.get_tracer_provider().add_span_processor( BatchSpanProcessor( LightstepOTLPSpanExporter( access_token=os.getenv("LIGHTSTEP_ACCESS_TOKEN") ) ) ) # Auto-instruments Flask ``` --- #### **362. How do you implement "real-time feature flag rollback"?** **Answer:** ```python from ldclient import get() @app.route('/flags/<flag_key>/rollback', methods=['POST']) @require_admin def rollback_flag(flag_key): flag = get().variation_detail(flag_key, None, None) if flag.value == "v2": get().variation(flag_key, None, "v1") # Rollback to v1 statsd.increment(f'flag.{flag_key}.rollback') return "Rolled back", 200 return "Already on v1", 200 ``` --- #### **363. How do you configure "infrastructure monitoring" with Netdata?** **Answer:** 1. Install Netdata agent: ```bash docker run -d --name=netdata \ -p 19999:19999 \ -v /proc:/host/proc:ro \ -v /sys:/host/sys:ro \ -v /var/run/docker.sock:/var/run/docker.sock:ro \ netdata/netdata ``` 2. Configure Flask-specific alerts in `health.d/python.conf`: ``` alarm: flask_high_latency on: flask_http_request_duration_seconds units: seconds info: High request latency warn: $this > 1 crit: $this > 2 ``` --- #### **364. How do you implement "real-time dependency health checks"?** **Answer:** ```python from flask import Blueprint health_bp = Blueprint('health', __name__) @health_bp.route('/dependencies') def dependencies(): results = {} for name, check in DEPENDENCY_CHECKS.items(): try: results[name] = {"status": "ok", "data": check()} except Exception as e: results[name] = {"status": "error", "message": str(e)} overall = "ok" if all(r["status"] == "ok" for r in results.values()) else "error" return jsonify(status=overall, dependencies=results), 200 if overall == "ok" else 503 ``` --- #### **365. How do you configure "infrastructure as code" with Ansible?** **Answer:** ```yaml # deploy.yml - name: Deploy Flask app hosts: webservers vars: app_version: "1.2.3" tasks: - name: Install dependencies apt: name: "{{ packages }}" vars: packages: - python3-pip - gunicorn - name: Deploy app unarchive: src: "https://s3.amazonaws.com/flask-app/{{ app_version }}.zip" dest: /opt/flask-app remote_src: yes - name: Start Gunicorn systemd: name: flask-app state: restarted daemon_reload: yes ``` --- #### **366. How do you implement "real-time canary analysis" with Grafana ML?** **Answer:** 1. Store metrics in Prometheus 2. Create Grafana ML panel: - **Algorithm**: Prophet - **Forecast horizon**: 1h - **Anomaly threshold**: 2 standard deviations 3. Alert when: ``` | actual - predicted | > threshold ``` --- #### **367. How do you configure "distributed tracing" with Instana?** **Answer:** ```python # Automatically instruments Flask when INSTANA_AGENT_KEY is set import instana # Environment variables: # INSTANA_AGENT_KEY=YOUR_KEY # INSTANA_SERVICE_NAME=flask-app # INSTANA_ZONE=production ``` --- #### **368. How do you implement "real-time infrastructure cost monitoring"?** **Answer:** ```python import boto3 def get_daily_cost(): client = boto3.client('ce') response = client.get_cost_and_usage( TimePeriod={ 'Start': (datetime.today() - timedelta(days=1)).strftime('%Y-%m-%d'), 'End': datetime.today().strftime('%Y-%m-%d') }, Granularity='DAILY', Metrics=['AmortizedCost'], GroupBy=[{'Type': 'DIMENSION', 'Key': 'SERVICE'}] ) return response['ResultsByTime'][0]['Groups'] @app.route('/cost') def cost(): return jsonify(get_daily_cost()) ``` --- #### **369. How do you configure "infrastructure monitoring" with Grafana Cloud?** **Answer:** 1. Add remote write to `prometheus.yml`: ```yaml remote_write: - url: "https://prometheus-us-central1.grafana.net/api/prom/push" basic_auth: username: YOUR_INSTANCE_ID password: YOUR_API_KEY ``` 2. Configure Flask metrics as in Q324 --- #### **370. How do you implement "real-time feature impact analysis"?** **Answer:** ```python from statsmodels.stats.proportion import proportions_ztest def analyze_feature_impact(feature, metric, variant="B"): # Get data for control (A) and variant (B) a_data = get_metric_data(feature, "A", metric) b_data = get_metric_data(feature, variant, metric) # Z-test for proportions count = [sum(a_data), sum(b_data)] nobs = [len(a_data), len(b_data)] z_stat, p_value = proportions_ztest(count, nobs) return { "p_value": p_value, "significant": p_value < 0.05, "effect_size": (b_data.mean() - a_data.mean()) / a_data.std() } ``` --- #### **371. How do you configure "serverless tracing" with AWS X-Ray for Lambda?** **Answer:** ```python from aws_xray_sdk.core import xray_recorder from aws_xray_sdk.ext.flask.middleware import XRayMiddleware # In Lambda handler def lambda_handler(event, context): xray_recorder.configure(service='Flask Lambda') XRayMiddleware(app, xray_recorder) # Manual subsegment for cold start detection with xray_recorder.in_subsegment('cold_start_check'): if context.get_remaining_time_in_millis() > 90000: xray_recorder.put_annotation('cold_start', True) return Mangum(app)(event, context) ``` --- #### **372. How do you implement "real-time database load forecasting"?** **Answer:** ```python from sklearn.ensemble import RandomForestRegressor def forecast_db_load(): # Features: hour_of_day, day_of_week, recent_load X, y = get_historical_data() model = RandomForestRegressor() model.fit(X, y) # Predict next hour next_hour = get_next_hour_features() predicted_load = model.predict([next_hour])[0] if predicted_load > MAX_CONNECTIONS * 0.8: trigger_read_replicas() ``` --- #### **373. How do you configure "infrastructure as code" with Terraform Cloud?** **Answer:** 1. Create `main.tf`: ```hcl terraform { cloud { organization = "my-org" workspaces { name = "flask-production" } } } module "flask" { source = "git::https://github.com/my-org/terraform-flask.git?ref=v1.0.0" env = "prod" } ``` 2. Set secrets in Terraform Cloud workspace variables --- #### **374. How do you implement "real-time anomaly detection" for user behavior?** **Answer:** ```python from sklearn.ensemble import IsolationForest def detect_anomalous_users(): # Features: request_count, error_rate, session_duration X = get_user_behavior_data() model = IsolationForest(contamination=0.01) model.fit(X) anomalies = model.predict(X) return User.query.filter(User.id.in_(anomalies == -1)).all() ``` --- #### **375. How do you configure "distributed tracing" with Signalfx?** **Answer:** ```python from signalfx_tracing import auto_instrument auto_instrument() # Environment variables: # SIGNALFX_ACCESS_TOKEN=YOUR_TOKEN # SIGNALFX_SERVICE_NAME=flask-app # SIGNALFX_TRACING_ENABLED=true ``` --- #### **376. How do you implement "real-time canary analysis" with Keptn?** **Answer:** 1. Define quality gates in `slo.yaml`: ```yaml spec_version: '1.0' comparison: compare_with: "single_result" include_result_with_score: "pass" number_of_comparison_results: 1 objectives: - sli: "error_rate" key_sli: false pass: [ { "criteria": [ "<=+10%" ] } ] warning: [ { "criteria": [ "<=800ms" ] } ] ``` 2. Trigger evaluation after canary deployment --- #### **377. How do you configure "infrastructure monitoring" with LogicMonitor?** **Answer:** 1. Install LogicMonitor collector 2. Create Python script datasource: ```python import requests from logicmonitor_sdk import Collector def get_flask_metrics(): resp = requests.get("http://localhost:5000/metrics") return { "request_rate": resp.json()["requests_per_sec"], "error_rate": resp.json()["errors_per_sec"] } Collector().send(get_flask_metrics()) ``` --- #### **378. How do you implement "real-time feature flag impact analysis"?** **Answer:** ```python def analyze_flag_impact(flag, metric): # Get data for enabled/disabled groups enabled = get_metric_data(flag, enabled=True, metric=metric) disabled = get_metric_data(flag, enabled=False, metric=metric) # T-test for means t_stat, p_value = ttest_ind(enabled, disabled) return { "p_value": p_value, "significant": p_value < 0.05, "lift": (enabled.mean() - disabled.mean()) / disabled.mean() } ``` --- #### **379. How do you configure "distributed tracing" with Datadog APM?** **Answer:** ```python from ddtrace import tracer @tracer.wrap(name="custom_operation", service="flask-app") def process_data(): # ... @app.route('/traced') def traced(): with tracer.trace("web_request"): process_data() return "Done" ``` *Environment:* ```bash DD_SERVICE=flask-app DD_ENV=production DD_TRACE_AGENT_URL=http://datadog:8126 ``` --- #### **380. How do you implement "real-time infrastructure cost optimization"?** **Answer:** ```python def optimize_costs(): # Get current utilization cpu_util = get_cpu_utilization() mem_util = get_memory_utilization() # Check if over-provisioned if cpu_util < 0.3 and mem_util < 0.4: current_size = get_instance_size() next_size = DOWNSCALE_MAP.get(current_size) if next_size: trigger_resize(next_size) # Check for idle resources if get_request_count(last_hour=1) == 0: trigger_suspend() ``` --- #### **381. How do you configure "serverless Flask" with Google Cloud Run?** **Answer:** 1. `Dockerfile`: ```dockerfile FROM python:3.10-slim WORKDIR /app COPY requirements.txt . RUN pip install -r requirements.txt COPY . . CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 app:app ``` 2. Deploy: ```bash gcloud run deploy flask-app \ --image gcr.io/project-id/flask-app \ --platform managed \ --region us-central1 \ --allow-unauthenticated ``` --- #### **382. How do you implement "real-time dependency vulnerability scanning"?** **Answer:** ```python import requests def scan_dependencies(): deps = get_requirements() response = requests.post( "https://api.snyk.io/test", json={"dependencies": deps}, headers={"Authorization": f"token {SNYK_TOKEN}"} ) return response.json()["vulnerabilities"] @app.route('/vulnerabilities') @require_admin def vulnerabilities(): return jsonify(scan_dependencies()) ``` --- #### **383. How do you configure "infrastructure as code" with Crossplane?** **Answer:** ```yaml apiVersion: database.example.org/v1alpha1 kind: PostgreSQLInstance metadata: name: flask-db spec: parameters: storageGB: 20 engineVersion: "12" writeConnectionSecretToRef: name: flask-db-conn --- apiVersion: compute.example.org/v1alpha1 kind: Deployment metadata: name: flask-app spec: template: spec: containers: - name: flask image: flask-app:1.0 env: - name: DB_HOST valueFrom: secretKeyRef: name: flask-db-conn key: host ``` --- #### **384. How do you implement "real-time user behavior clustering"?** **Answer:** ```python from sklearn.cluster import KMeans def cluster_users(): # Features: session_duration, page_views, conversion X = get_user_features() model = KMeans(n_clusters=3) clusters = model.fit_predict(X) # Assign clusters to users for user, cluster in zip(User.query.all(), clusters): user.behavior_cluster = cluster db.session.commit() ``` --- #### **385. How do you configure "distributed tracing" with Jaeger in Kubernetes?** **Answer:** 1. Deploy Jaeger operator: ```bash kubectl create -f https://raw.githubusercontent.com/jaegertracing/jaeger-operator/master/deploy/crds/jaegertracing.io_jaegers_crd.yaml ``` 2. Create Jaeger instance: ```yaml apiVersion: jaegertracing.io/v1 kind: Jaeger metadata: name: flask-jaeger spec: strategy: production collector: options: log-level: info ``` 3. Configure Flask as in Q333 --- #### **386. How do you implement "real-time feature flag risk assessment"?** **Answer:** ```python def assess_flag_risk(flag): # Factors: user impact, error rate, business criticality user_impact = get_affected_users(flag) / total_users() error_rate = get_error_rate(flag) criticality = FEATURE_CRITICALITY.get(flag, 1.0) # Risk score (0-10) risk = min(10, (user_impact * 5) + (error_rate * 30) + (criticality * 2)) return { "risk_score": risk, "high_risk": risk > 7, "factors": { "user_impact": user_impact, "error_rate": error_rate, "criticality": criticality } } ``` --- #### **387. How do you configure "infrastructure monitoring" with Prometheus Operator?** **Answer:** ```yaml apiVersion: monitoring.coreos.com/v1 kind: ServiceMonitor metadata: name: flask-monitor spec: selector: matchLabels: app: flask-app endpoints: - port: web interval: 15s path: /metrics --- apiVersion: monitoring.coreos.com/v1 kind: PrometheusRule metadata: name: flask-alerts spec: groups: - name: flask rules: - alert: HighErrorRate expr: rate(flask_http_request_errors_total[5m]) / rate(flask_http_requests_total[5m]) > 0.05 for: 10m labels: severity: critical ``` --- #### **388. How do you implement "real-time capacity planning" for Redis?** **Answer:** ```python def forecast_redis_usage(): # Get historical memory usage timestamps, usage = get_redis_memory_history() # Linear regression model = LinearRegression().fit( np.array(timestamps).reshape(-1, 1), usage ) # Predict when 80% capacity is reached current = get_redis_memory() capacity = get_redis_maxmemory() days_to_full = (capacity * 0.8 - current) / model.coef_[0] if days_to_full < 7: trigger_resize() ``` --- #### **389. How do you configure "distributed tracing" with OpenTelemetry Collector?** **Answer:** 1. `otel-collector.yaml`: ```yaml receivers: otlp: protocols: grpc: http: exporters: jaeger: endpoint: "jaeger:14250" logging: service: pipelines: traces: receivers: [otlp] exporters: [jaeger, logging] ``` 2. Flask configuration as in Q201 --- #### **390. How do you implement "real-time feature flag compliance checks"?** **Answer:** ```python def check_compliance(flag): # Check against regulatory requirements requirements = get_regulatory_requirements() violations = [] for req in requirements: if req.applies_to(flag) and not req.is_satisfied(flag): violations.append({ "requirement": req.id, "description": req.description }) return { "compliant": len(violations) == 0, "violations": violations } ``` --- #### **391. How do you configure "infrastructure as code" with AWS SAM?** **Answer:** ```yaml # template.yaml AWSTemplateFormatVersion: '2010-09-09' Transform: AWS::Serverless-2016-10-31 Resources: FlaskFunction: Type: AWS::Serverless::Function Properties: CodeUri: app/ Handler: lambda_handler.lambda_handler Runtime: python3.9 Events: Api: Type: Api Properties: Path: /{proxy+} Method: ANY Environment: Variables: SECRET_KEY: !Ref SecretKey Tracing: Active SecretKey: Type: AWS::SSM::Parameter Properties: Type: SecureString Value: !Ref SecretKeyValue ``` --- #### **392. How do you implement "real-time anomaly detection" for API usage?** **Answer:** ```python from sklearn.covariance import EllipticEnvelope def detect_anomalous_api_usage(): # Features: requests_per_min, endpoints_used, user_agents X = get_api_usage_data() model = EllipticEnvelope(contamination=0.01) model.fit(X) anomalies = model.predict(X) return APIKey.query.filter(APIKey.id.in_(anomalies == -1)).all() ``` --- #### **393. How do you configure "distributed tracing" with AWS X-Ray for ECS?** **Answer:** 1. Add X-Ray daemon sidecar: ```yaml # task-definition.json "containerDefinitions": [ { "name": "xray-daemon", "image": "amazon/aws-xray-daemon", "cpu": 32, "memory": 256, "portMappings": [{ "containerPort": 2000, "protocol": "udp" }] }, { "name": "flask-app", "image": "flask-app:latest", "environment": [{ "name": "AWS_XRAY_DAEMON_ADDRESS", "value": "xray-daemon:2000" }] } ] ``` 2. Configure Flask as in Q304 --- #### **394. How do you implement "real-time feature flag dependency analysis"?** **Answer:** ```python def analyze_flag_dependencies(flag): # Get all flags used in same code paths dependencies = set() for endpoint in get_endpoints_using_flag(flag): for other_flag in get_flags_in_endpoint(endpoint): if other_flag != flag: dependencies.add(other_flag) # Calculate impact score impact = 0 for dep in dependencies: impact += get_affected_users(dep) * FLAG_CRITICALITY[dep] return { "dependencies": list(dependencies), "impact_score": impact, "high_impact": impact > 1000 } ``` --- #### **395. How do you configure "infrastructure monitoring" with Sysdig Secure?** **Answer:** 1. Install Sysdig agent with policy: ```yaml apiVersion: apps/v1 kind: DaemonSet spec: template: spec: containers: - name: sysdig-agent env: - name: SECURE_POLICY_FILE value: | - name: Flask Security Policy description: Security rules for Flask apps rules: - rule: "Flask Admin Access" condition: kubernetes.pod.name matches "flask-*" and proc.name = "flask" and fd.name = "/admin" actions: - log - alert ``` --- #### **396. How do you implement "real-time database schema drift detection"?** **Answer:** ```python def detect_schema_drift(): # Get current schema current_schema = get_db_schema() # Compare with golden schema with open('golden_schema.json') as f: golden_schema = json.load(f) drift = [] for table in golden_schema: if table not in current_schema: drift.append(f"Missing table: {table}") continue for column in golden_schema[table]: if column not in current_schema[table]: drift.append(f"Missing column: {table}.{column}") if drift: send_alert(f"Schema drift detected: {drift}") return drift ``` --- #### **397. How do you configure "distributed tracing" with Azure Application Insights?** **Answer:** ```python from opencensus.ext.azure.trace_exporter import AzureExporter from opencensus.trace.samplers import ProbabilitySampler from opencensus.trace.tracer import Tracer tracer = Tracer( exporter=AzureExporter( instrumentation_key=os.getenv('APPINSIGHTS_INSTRUMENTATIONKEY') ), sampler=ProbabilitySampler(1.0) ) @app.route('/traced') def traced(): with tracer.span(name="web_request"): # ... ``` --- #### **398. How do you implement "real-time infrastructure compliance checks"?** **Answer:** ```python def check_infra_compliance(): checks = [ SecurityCheck( name="SSH Restriction", description="SSH only from bastion", check=lambda: get_security_groups().all(sg.ports_open('22') == {'bastion'}) ), SecurityCheck( name="Encryption at Rest", description="All databases encrypted", check=lambda: get_databases().all(db.encrypted) ) ] results = [check.run() for check in checks] return { "compliant": all(r.passed for r in results), "results": [r.to_dict() for r in results] } ``` --- #### **399. How do you configure "serverless Flask" with Azure Functions?** **Answer:** 1. `function_app/__init__.py`: ```python import azure.functions as func from flask import Flask app = Flask(__name__) @app.route('/') def home(): return "Hello from Flask!" def main(req: func.HttpRequest) -> func.HttpResponse: return func.WsgiMiddleware(app).handle(req, None) ``` 2. `host.json`: ```json { "version": "2.0", "extensions": { "http": { "routePrefix": "" } } } ``` --- #### **400. How do you implement "real-time cost anomaly detection" for cloud resources?** **Answer:** ```python from sklearn.ensemble import IsolationForest def detect_cost_anomalies(): # Features: daily_cost, resource_count, usage_hours X = get_historical_costs() model = IsolationForest(contamination=0.05) model.fit(X) anomalies = model.predict(X) current_cost = get_current_cost() if anomalies[-1] == -1 and current_cost > X['cost'].mean() * 2: trigger_investigation() return anomalies[-1] == -1 ``` --- **Part 5 (Questions 401–500) is the final installment!**