examples/features/loadbalancing: Add custom lb example #6649
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| # custom_round_robin | ||
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| ``` |
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Please add a similar explanation of this case, keeping a similar structure, rather than just starting with output text. "The third client is configured to use a custom ............"
| @@ -84,11 +89,24 @@ func main() { | |||
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| fmt.Println("--- calling helloworld.Greeter/SayHello with round_robin ---") | |||
| makeRPCs(roundrobinConn, 10) | |||
| // You can also plug in your own custom lb policy, which needs to be | |||
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Add a blank line above this for better visual separation please.
| // configurable. This n is configurable. Try changing it and see how the | ||
| // behavior changes. | ||
| customroundrobinConn, err := grpc.Dial( | ||
| fmt.Sprintf("%s:///%s", exampleScheme, exampleServiceName), |
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Let's pull this out at the top of the function:
target := fmt.Sprintf("%s:///%s", exampleScheme, exampleServiceName)| serviceconfig.LoadBalancingConfig `json:"-"` | ||
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| // N represents how often pick iterations chose the second SubConn | ||
| // in the list. Defaults to 3. |
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Ah good catch. Switched the default in ParseConfig() to 3.
| func (customRoundRobinBuilder) Build(cc balancer.ClientConn, bOpts balancer.BuildOptions) balancer.Balancer { | ||
| crr := &customRoundRobin{} | ||
| baseBuilder := base.NewBalancerBuilder(customRRName, crr, base.Config{HealthCheck: true}) | ||
| crr.Balancer = baseBuilder.Build(cc, bOpts) |
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I'm really not a fan of the base balancer...are we sure we want users using it as a template for how to do their own LB policy? I think it would be better to show the actual connection management APIs here instead.
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Switched to petiole policy wrapping pick first after offline discussion.
| } | ||
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| // Following is an example name resolver implementation. Read the name | ||
| // resolution example to learn more about it. | ||
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| type exampleResolverBuilder struct{} |
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I don't believe this example intends to show off custom resolvers - can this be replaced with the manual resolver instead? We may not have had it when this was created.
| @@ -123,4 +141,87 @@ func (*exampleResolver) Close() {} | |||
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| func init() { | |||
| resolver.Register(&exampleResolverBuilder{}) | |||
| balancer.Register(&customRoundRobinBuilder{}) | |||
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Maybe put the custom LB policy into its own file (or even its own sub-package), since that's how we expect it to be used typically?
| } | ||
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| func (crr *customRoundRobin) Build(info base.PickerBuildInfo) balancer.Picker { | ||
| if len(info.ReadySCs) == 0 { |
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If you want to make this deterministic, then also do this until len(info.ReadySCs) == 2?
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Made deterministic in new PR based off child balancer connectivity states.
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Opened a new PR #6691 containing all the offline discussion decisions such as making Custom Load Balancer a petiole policy wrapping pick_first load balancers. Made a whole new example because this example is outdated and shows concepts like custom resolvers, and new example needs to use endpoints. |
This PR adds a custom lb example, with a custom lb deployed as the top level balancer of the channel through service config. This scales up a previous example
RELEASE NOTES: