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Upstream Service

An upstream service is a service that another service (the downstream service) depends on or receives data from. The term is commonly used in distributed systems, microservices, and networking.

Key Concepts:

  1. Data Flow Perspective

    • Upstream Service: Sends data or performs operations that another service relies on.
    • Downstream Service: Receives data or responses from the upstream service.

  2. Examples in Different Contexts

    • Microservices:
      • A payment service (downstream) may call an authentication service (upstream) to verify user credentials.
    • Networking:
      • A web browser (downstream) requests data from a web server (upstream).
    • APIs:
      • A frontend app (downstream) fetches data from a backend API (upstream).

  3. Failure Propagation

    • If an upstream service fails, downstream services may be affected unless they have fallback mechanisms (like caching or retries).