gRPC for internal communication in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why choose gRPC over REST for internal microservice communication?

Consider a system where multiple microservices communicate internally. Which of the following is the main advantage of using gRPC instead of REST for this internal communication?

A gRPC only supports synchronous communication, which simplifies service design.

B gRPC uses HTTP/2 which allows multiplexing multiple requests over a single connection, reducing latency.

C gRPC requires no schema definition, so services can evolve independently without coordination.

D gRPC messages are always human-readable JSON, making debugging easier than REST.

💡 Hint

Think about how network efficiency and protocol features affect communication speed and resource use.

gRPC uses HTTP/2 which supports multiplexing multiple requests on a single connection, reducing latency and improving throughput compared to REST which typically uses HTTP/1.1. This makes gRPC efficient for internal microservice communication.

❓ Architecture

intermediate

Designing service discovery with gRPC in microservices

You have multiple microservices communicating via gRPC. Which approach best supports dynamic service discovery to handle scaling and failures?

A Let clients broadcast requests to all possible service instances and accept the first response.

B Hardcode all service IP addresses in client configurations to avoid runtime lookups.

C Use a centralized service registry where services register their addresses; clients query this registry before making gRPC calls.

D Use DNS round-robin with static IPs for all services without any registry.

💡 Hint

Think about how services can find each other reliably when instances change dynamically.

A centralized service registry allows services to register their current addresses and clients to discover them dynamically. This supports scaling and failure handling better than static configurations or broadcasting.

❓ scaling

advanced

Handling high load with gRPC streaming in microservices

Your microservice needs to send a continuous stream of updates to clients using gRPC. What is the best way to handle backpressure and avoid overwhelming clients?

A Implement client-side flow control by using gRPC's built-in flow control mechanisms to regulate message rates.

B Send all updates as fast as possible and rely on clients to buffer messages.

C Use multiple parallel gRPC streams per client to increase throughput without flow control.

D Switch to REST polling instead of streaming to avoid backpressure issues.

💡 Hint

Consider how gRPC supports managing message flow between sender and receiver.

gRPC supports flow control in streaming RPCs, allowing clients to control how many messages they can handle. This prevents overwhelming clients and manages backpressure effectively.

❓ tradeoff

advanced

Tradeoffs of using gRPC with Protocol Buffers vs JSON over HTTP for internal APIs

Which of the following is a correct tradeoff when choosing gRPC with Protocol Buffers over JSON/HTTP for internal APIs?

A gRPC does not support streaming, so JSON/HTTP is better for real-time data.

B gRPC with Protocol Buffers is easier to debug with plain text messages compared to JSON.

C JSON/HTTP APIs are faster than gRPC because JSON parsing is simpler than Protocol Buffers decoding.

D gRPC with Protocol Buffers offers better performance and smaller message size but requires strict schema management.

💡 Hint

Think about message size, speed, and schema requirements.

gRPC uses Protocol Buffers which are compact and fast but require predefined schemas. JSON is human-readable and flexible but larger and slower to parse.

❓ estimation

expert

Estimating capacity for gRPC internal communication in a microservice system

You have 100 microservice instances communicating via gRPC. Each instance sends 50 requests per second to 10 other instances. Each request message is 2KB and response is 3KB. Estimate the total network bandwidth needed for gRPC communication in Mbps.

A Approximately 200 Mbps

B Approximately 80 Mbps

C Approximately 120 Mbps

D Approximately 300 Mbps

💡 Hint

Calculate total messages per second and multiply by message sizes, then convert bytes to bits and to Mbps.

Total requests per second = 100 instances * 50 requests/sec * 10 targets = 50,000 requests/sec.
Each request + response size = 2KB + 3KB = 5KB = 5 * 1024 bytes = 5120 bytes.
Total bytes per second = 50,000 * 5120 = 256,000,000 bytes/sec.
Convert to bits: 256,000,000 * 8 = 2,048,000,000 bits/sec.
Convert to Mbps: 2,048,000,000 / 1,000,000 = 2048 Mbps, which is much higher than the options given.