mirror of https://github.com/status-im/consul.git
75 lines
2.4 KiB
Go
75 lines
2.4 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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package dependency
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import (
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"context"
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"github.com/hashicorp/consul/internal/controller"
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"github.com/hashicorp/consul/proto-public/pbresource"
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)
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// DependencyTransform is used when the incoming resource from a watch needs to
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// be transformed to a different resource or set of resources and then have
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// a DependencyMapper executed on each element in that result set. This should
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// only be needed for dealing with more complex dependency relationships where
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// the managed type and watched type are not directly related.
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type DependencyTransform func(
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ctx context.Context,
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rt controller.Runtime,
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res *pbresource.Resource,
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) ([]*pbresource.Resource, error)
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// MapperWithTransform will execute the provided DependencyTransform and then execute
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// the provided DependencyMapper once for each of the resources output by the transform.
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// The DependencyMapper outputs will then be concatenated together to form the whole
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// set of mapped Requests.
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func MapperWithTransform(mapper controller.DependencyMapper, transform DependencyTransform) controller.DependencyMapper {
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return func(ctx context.Context, rt controller.Runtime, res *pbresource.Resource) ([]controller.Request, error) {
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transformed, err := transform(ctx, rt, res)
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if err != nil {
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return nil, err
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}
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var reqs []controller.Request
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for _, res := range transformed {
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newReqs, err := mapper(ctx, rt, res)
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if err != nil {
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return nil, err
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}
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reqs = append(reqs, newReqs...)
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}
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return reqs, nil
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}
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}
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// TransformChain takes a set of transformers and will execute them as a pipeline.
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// The first transformer will output some resources. Those resources will then be
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// used as inputs to the next transform. The chain will then continue until all
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// transformers have been run.
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func TransformChain(transformers ...DependencyTransform) DependencyTransform {
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return func(ctx context.Context, rt controller.Runtime, res *pbresource.Resource) ([]*pbresource.Resource, error) {
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toTransform := []*pbresource.Resource{res}
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for _, transform := range transformers {
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var nextResources []*pbresource.Resource
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for _, res := range toTransform {
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next, err := transform(ctx, rt, res)
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if err != nil {
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return nil, err
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}
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nextResources = append(nextResources, next...)
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}
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toTransform = nextResources
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}
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return toTransform, nil
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}
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}
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