mirror of https://github.com/grpc/grpc-go.git
66 lines
1.9 KiB
Markdown
66 lines
1.9 KiB
Markdown
# Retry
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This example shows how to enable and configure retry on gRPC clients.
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## Documentation
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[gRFC for client-side retry support](https://github.com/grpc/proposal/blob/master/A6-client-retries.md)
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## Try it
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This example includes a service implementation that fails requests three times with status
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code `Unavailable`, then passes the fourth. The client is configured to make four retry attempts
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when receiving an `Unavailable` status code.
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First start the server:
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```bash
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go run server/main.go
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```
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Then run the client:
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```bash
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go run client/main.go
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```
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## Usage
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### Define your retry policy
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Retry is enabled via the service config, which can be provided by the name resolver or
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a DialOption (described below). In the below config, we set retry policy for the
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"grpc.example.echo.Echo" method.
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MaxAttempts: how many times to attempt the RPC before failing.
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InitialBackoff, MaxBackoff, BackoffMultiplier: configures delay between attempts.
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RetryableStatusCodes: Retry only when receiving these status codes.
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```go
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var retryPolicy = `{
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"methodConfig": [{
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// config per method or all methods under service
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"name": [{"service": "grpc.examples.echo.Echo"}],
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"waitForReady": true,
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"retryPolicy": {
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"MaxAttempts": 4,
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"InitialBackoff": ".01s",
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"MaxBackoff": ".01s",
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"BackoffMultiplier": 1.0,
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// this value is grpc code
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"RetryableStatusCodes": [ "UNAVAILABLE" ]
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}
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}]
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}`
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```
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### Providing the retry policy as a DialOption
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To use the above service config, pass it with `grpc.WithDefaultServiceConfig` to
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`grpc.Dial`.
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```go
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conn, err := grpc.Dial(ctx,grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithDefaultServiceConfig(retryPolicy))
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```
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