Polly
Polly is a .NET resilience library for defining policies that handle transient faults and control behaviors such as retries, timeouts, circuit breakers, and fallbacks.
ASP.NET Core in Action, 3e
Polly is a .NET resilience library for defining policies that handle faults and control retries, timeouts, circuit breakers, and related behaviors.
- How it is used
- Handles transient failures when .NET applications call remote HTTP APIs through HttpClient.
- How deep it goes
- Explains package setup, handler-pipeline integration, retry timing, supported errors, and policy trade-offs without detailing Polly internals.
- Examples
- Uses an ExchangeRatesClient with three delayed retries and a PolicyHttpMessageHandler flow diagram.
- What you can do after
- Operate/configure Polly through AddTransientHttpErrorPolicy() to retry selected transient HTTP failures automatically.
.NET in Action, Second Edition
Polly is a .NET resilience library for expressing policies such as retries, circuit breakers, timeouts, and fallbacks.
- How it is used
- Applies resilience policies to HTTP requests and other operations that need handling beyond EF Core’s built-in retries.
- How deep it goes
- Builds and registers retry policies, explains back-off and alternatives, then surveys timeouts, fallbacks, circuit breakers, bulkheads, and rate limiting.
- Examples
- Uses an XKCD API client, mocked HTTP handler, transient errors, HTTP 429 responses, and exponential retry delays.
- What you can do after
- Apply it via Microsoft.Extensions.Http.Polly to configure, customize, and test resilience policies for HttpClient operations.
Related concepts
- Microsoft.Extensions.Http.Pollyused by · Microsoft.Extensions.Http.Polly is a .NET integration library that applies Polly resilience policies to HttpClient instances created by IHttpClientFactory.
- retryuses · A retry is a subsequent attempt to perform an operation after an earlier attempt fails or does not complete successfully.
- transient failureaddresses · A transient failure is a temporary failure condition that may resolve on its own or not recur when an operation is attempted again.
- timeoutuses · A timeout is a configured time limit after which an incomplete operation or wait is stopped, abandoned, or treated as unsuccessful.
- rate limituses · A rate limit is a bound on the frequency or volume of operations permitted within a defined interval, scope, or concurrency limit.
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