Development with AWS Services

DVA-C02 · 96 questions

• A city permitting portal must wake the intake service only when a payment clears, without a nightly batch job polling a database. Which application pattern should the developers implement?
• A county clerk wants building permits, fees, and inspections as separately deployable services, each with its own data store, so one team's release does not freeze the others. Which pattern matches that goal?
• A small township library app is one deployable unit sharing one schema, maintained by three staff. Leadership asks whether splitting into ten services is mandatory on AWS. Which statement is accurate?
• After a citizen submits a parks reservation, payment, calendar, and email services each listen for the same domain events and act without a central conductor. Which pattern is this?
• A business-license renewal must run identity check, fee calculation, payment, then license PDF generation in a fixed order, and the help desk needs a visible workflow state to inspect. Which pattern fits best?
• When a snow-emergency flag flips, the same alert must reach SMS subscribers, a dashboard queue, and a logging archive without the weather service calling each consumer itself. Which pattern should developers use?
• A recreation registration API keeps shopping-cart selections only in server memory on one instance; scaling out drops carts mid-checkout. What change best aligns with a stateless compute pattern?
• A municipal Lambda behind API Gateway must remain safe to scale to zero and multiply under load. Developers debate storing citizen wizard progress inside the function container. What should they do?
• The tax portal's invoice service hard-codes direct HTTPS calls and shared database tables into the payment service, so either team's change breaks the other at deploy time. What problem is this, and what direction improves it?
• A 311 photo-upload API currently waits for virus scan and thumbnail generation before returning HTTP 200, causing citizen timeouts on large images. What should developers change?
• A Python permit service calling a third-party address validator fails the whole submit when the vendor blips for two seconds. Which resilience approach should developers apply in application code?
• API Gateway fronts a grant-application API. Invalid ZIP codes and missing required fields currently reach Lambda and clutter logs. Where should developers enforce request validation first?
• A legacy inspection API returns HTTP 200 with an error string in the body. Mobile clients need proper 4xx/5xx status codes and a cleaned JSON shape without rewriting every backend method yet. What should developers use?
• A parks Lambda team wants fast unit tests on laptops before any cloud deploy, mocking AWS calls rather than hitting real DynamoDB. Which practice matches that goal?
• A code-enforcement app must enqueue failed door-hanger print jobs for later retry without blocking the inspector's UI thread. Which approach should the application code take?
• Transit dispatch needs many independent listeners when a bus route detour is published, without the publisher knowing each listener. Which messaging approach should application code use?
• A TypeScript citizen-portal backend must list objects in a departmental S3 bucket using credentials from the runtime role—not hard-coded keys in source. How should it call AWS?
• Before committing, a developer verifies a new DynamoDB table name and an IAM permission boundary using CLI calls from CloudShell against the shared sandbox account. What does this illustrate?
• Water-meter gateways emit continuous reading events that a billing enrichment job must process as a stream, not as overnight CSV drops only. Which AWS approach fits application-level streaming ingest?
• A junior city developer asks Amazon Q Developer to draft a Lambda handler skeleton that reads an SQS event and writes to DynamoDB, then reviews the suggestion for secrets and correctness. Which statement is accurate?
• When an S3 object lands in the permits/incoming/ prefix, a rule should start a validation workflow without polling the bucket. Which service pattern should developers implement?
• Multiple municipal apps publish inspection.completed events; a single analytics consumer should not be wired into each publisher's code. Which EventBridge approach keeps publishers decoupled?
• A courts calendar sync calls a vendor API that returns intermittent HTTP 503s. Naive immediate retries stampede the vendor. What retry strategy should application code implement?
• If the external GIS geocoder is down, the address-lookup feature should fail fast after repeated errors and serve a degraded enter-manually path instead of hanging every request. Which pattern is this?
• A Step Functions-style intake flow needs distinct handling for poison messages versus retryable timeouts when calling a payment gateway. What should developers do?
• A city's vital-records print shop falls behind when peak online orders hit printers synchronously from the web tier. Which change best loosens coupling and absorbs the spike?
• A single case-closed event must feed both a searchable archive queue and a metrics queue, and each consumer must fail and scale on its own. Which pattern should the developer implement?
• A multi-step business-grant approval needs wait states for human review, parallel document checks, and clear success and fail paths. Which AWS service should orchestrate that workflow?
• A mobile field-inspection app needs flexible, client-defined field selection over a graph of related assets instead of a fixed REST resource for every screen. Which API approach fits best?
• A public open-data JSON API needs API keys, throttling, and stage-based deploys in front of a simple CRUD Lambda backend. Which service should front the API?
• A cashier kiosk must show the tax-due balance before printing a receipt; waiting a minute for eventual consistency is unacceptable for that click. Which interaction style should the balance lookup use?
• Council wants the citizen auth gateway to scale horizontally without sticky sessions pinned to a particular EC2 host. Which session approach supports that goal?
• When a hydrant is flagged, three systems should each react on their own with no central state machine and no ordered multi-step waits. Which coordination style fits?
• A records-purge job lists thousands of S3 inventory objects but stops halfway because the code ignores continuation tokens. What should the developer fix?
• Amazon SQS can deliver a meter-reading message more than once, and blindly inserting each delivery would double-bill residents. How should the consumer be designed?
• After maximum receives, unprocessable code-violation payloads must not block the main SQS backlog forever. What should the team configure?
• A developer's unit-test suite creates real SNS topics in the production account during CI because mocks were skipped. What is the correct testing practice?
• A script every five minutes scans a DynamoDB table for unpaid invoices to email reminders, burning read capacity mostly on no-op scans. Which approach better fits an event-driven design?
• A dashboard aggregates three municipal APIs, and one slow dependency should not blank the entire page. Which resilience approach should the developer apply?
• Inspection status updates for one parcel must process in order, but citywide throughput still matters. Which messaging choice best matches that tradeoff?
• A Lambda function must read an Aurora database that is reachable only on private subnets inside the city's VPC. What must the developer configure?
• Feature flags and non-secret DynamoDB table names for a grants Lambda should change per stage without rebuilding the deployment package each time. Where should that configuration live?
• A PDF-merge Lambda for council packets is CPU-bound and slow at 128 MB. What should the developer remember when tuning memory?
• A sudden open-enrollment spike exhausts account concurrency and starves an unrelated payroll Lambda in the same account. How should critical capacity be protected?
• A Lambda that calls a slow legacy mainframe still uses the default 3-second timeout and fails mid-transaction even though the business allows 45 seconds. What should the developer do?
• A team migrates a Node.js handler to Python but leaves the handler string pointing at the old export name, causing runtime import errors. What must be aligned?
• Three municipal Lambdas share the same GIS SDK and logging library, and copying those zip dependencies into every function bloats packages. What should the team use?
• Ops wants a lightweight sidecar-style agent to ship enhanced telemetry from many Lambdas without rewriting business handlers each time. Which Lambda feature fits?
• New objects in an S3 evidence bucket should invoke a redaction function automatically. How should that integration be configured?
• On success, a license-PDF Lambda should hand a summary payload to EventBridge; on failure after retries, it should notify an ops SQS queue. Which feature routes those outcomes?
• A city newsletter Lambda is invoked asynchronously to send bulk alerts. After Lambda exhausts its async retries, failed deliveries must land somewhere the ops team can inspect and replay later. What should the developer configure?
• Before promoting a citizen-portal Lambda to the shared test stage, developers must invoke it locally with a realistic API Gateway proxy event. Which approach best meets that need?
• A voter-registration Lambda must PutItem new registrations and Query by voter ID in DynamoDB while running under the function's execution role. How should the developer implement this?
• Batch meter-reading events arrive on Amazon SQS. A Lambda function should process messages in batches and report which messages failed so successful ones are not reprocessed. What should the developer enable?
• A parks department needs a public HTTPS endpoint that maps HTTP routes to Lambda handlers and can add JWT authorizers later. Which integration should the developer choose?
• A Java Lambda that generates rare monthly utility reports shows multi-second cold starts when the first citizen clicks after long idle periods. Idle cost is a concern for infrequent use. What is the most appropriate performance approach?
• A simple JSON-transform Lambda ships a 250 MB deployment package, slowing updates and cold starts. What should the developer do?
• Parking-sensor heartbeats arrive on Amazon Kinesis. Within seconds of arrival, records must be enriched and written to DynamoDB. Which pattern should the developer use?
• A multi-step FOIA redaction workflow must run separate Lambda tasks with retries per state rather than one mega-function. What should the developer use?
• Product wants richer success payloads routed to a downstream event bus when a Lambda finishes, not only failure capture after async retries. Which capability should the developer prefer?
• A media-processing Lambda must unpack a ZIP of permit drawings into a few hundred MB of scratch space before uploading results to S3. Where should that ephemeral workspace live?
• An SQS-triggered fee-posting Lambda can be invoked more than once for the same message because of at-least-once delivery. Double posts would corrupt municipal ledgers. What must the handler do?
• An S3 bucket event cannot invoke a redaction Lambda because the function's resource-based policy does not allow the bucket's principal. What should the developer fix?
• During open enrollment, API clients receive HTTP 429 responses while a Lambda function’s reserved concurrency is set far below actual demand. Code errors are not appearing in logs. What is the likely diagnosis and fix direction?
• Weather alerts published to Amazon SNS must fan into a Lambda that opens incident tickets. How should the developer connect them?
• The same grant-scoring Lambda code needs higher memory and longer timeout in load-test than in production. How should configuration differ across environments?
• Business rules for grant scoring are tangled with AWS SDK calls inside one Lambda handler, making unit tests slow and brittle. What structural change helps?
• A poison record in a Kinesis batch causes the water-quality Lambda to fail the entire batch and stall shard iterator progress. What should the developer apply?
• Several municipal Lambdas need shared read access to a large GIS tile cache with POSIX file semantics that exceed practical /tmp size. What should they mount?
• Encoding 45-minute city council session videos exceeds practical Lambda maximum duration, yet ops only keeps raising the function timeout. What should the team do instead?
• A 911-adjacent callback API on Lambda must keep consistently low latency; the agency accepts paying for idle warm capacity. Which setting addresses cold starts?
• A Lambda that only writes to one DynamoDB table was given AdministratorAccess to unblock a sprint. What should replace that policy?
• A city stores every parking ticket under the DynamoDB partition key CITY#ALL, causing a hot partition during ticket season. How should the key design change?
• After a cashier posts a fee, the next read of the resident balance on another path sometimes shows the old amount when using eventually consistent reads. Staff need the latest balance immediately. What should the developer select?
• A dashboard refreshes all open cases citywide by running a full DynamoDB table Scan every minute, consuming excess capacity. What should the developer prefer?
• A city case-management app must fetch a case by caseId and also list a citizen’s cases by citizenId plus filing date. Why is a single partition key alone a poor fit?
• County inspectors must filter field jobs by status and district without table scans. Status alone has only a few values. Which DynamoDB design best supports that query?
• Within one municipal permit partition key, clerks need items sorted either by create-date or by fee-amount without copying the table. Which DynamoDB feature fits?
• A Node.js inspection service must persist a nested checklist object to DynamoDB without turning numbers into unexpected strings or dropping nested maps. What should the team use?
• A seasonal city tax portal sees quiet winters and sharp April filing spikes. Which DynamoDB capacity approach best matches that traffic shape?
• Finance must move funds across multiple appropriation accounts in one ACID transaction with multi-row SQL updates. Which data store choice fits best for the application?
• Public-works as-built PDF plan sets are large. How should a developer persist them alongside DynamoDB case metadata?
• Permit drawings older than seven years must move to cheaper storage automatically yet remain restorable for audits. What should the developer configure?
• Transient email-verification codes for citizen accounts should expire automatically without a nightly sweeper job. Which DynamoDB feature should the app use?
• A read-heavy open-data catalog hammers Aurora with identical queries for popular datasets. What application-level change reduces database load?
• After publishing a corrected fee schedule, citizens still see old prices for minutes because the app caches by TTL only. What should developers do?
• Staff need typo-tolerant full-text search across free-text complaint narratives, not just exact DynamoDB key lookups. Which service fits that access pattern?
• Analysts need ad-hoc SQL over years of CloudTrail and app logs landed as Parquet on S3 without standing up a permanent warehouse cluster. Which approach fits?
• A single EC2 report worker needs local scratch disk; a fleet of workers needs a shared POSIX tree; durable citizen blobs need object storage. Which pairing is correct?
• Two clerks may update the same case-notes item concurrently. How should the app prevent silent overwrites in DynamoDB?
• A globally replicated municipal settings table holds feature flags for kiosk apps that can tolerate brief staleness. Which DynamoDB read consistency choice is appropriate by default?
• Embedding base64 building photos in DynamoDB items approaches size limits and slows reads. What should developers do?
• When a parcel record changes in DynamoDB, a search index and an audit log must update. Which integration pattern should the developer use?
• Hundreds of concurrent Lambdas each open a new RDS connection per invoke and exhaust maxconnections. What should the team implement?
• A team debates one DynamoDB table with careful keys versus many tables that mirror a relational permits schema. What modeling guidance should developers follow?
• Citizens see intermittent ProvisionedThroughputExceeded during enrollment peaks. Besides blind retries, what should developers address?