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Resolver Reference

Writing a resolver is made easier with the github.com/tektoncd/pipeline/pkg/resolution/resolver/framework package. This package exposes a number of interfaces that let your code control what kind of behaviour it should have when running.

To get started really quickly see the resolver template, or for a howto guide see how to write a resolver.

The Resolver Interface

Implementing this interface is required. It provides just enough configuration for the framework to get a resolver running.

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Method to Implement	Description
Initialize	Use this method to perform any setup required before the resolver starts receiving requests.
GetName	Use this method to return a name to refer to your Resolver by. e.g. "Git"
GetSelector	Use this method to specify the labels that a resolution request must have to be routed to your resolver.
Validate	Use this method to validate the resolution Spec given to your resolver.
Resolve	Use this method to perform get the resource based on the ResolutionRequestSpec as input and return it, along with any metadata about it in annotations. Errors returned by this method mark the ResolutionRequest as Failed, unless the error type is considered transient (e.g. a Kubernetes request timeout or etcd leader changes).

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Method to Implement	Description
Initialize	Use this method to perform any setup required before the resolver starts receiving requests.
GetName	Use this method to return a name to refer to your Resolver by. e.g. "Git"
GetSelector	Use this method to specify the labels that a resolution request must have to be routed to your resolver.
ValidateParams	Use this method to validate the params given to your resolver.
Resolve	Use this method to perform get the resource based on params as input and return it, along with any metadata about it in annotations

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The ConfigWatcher Interface

Implement this optional interface if your Resolver requires some amount of admin configuration. For example, if you want to allow admin users to configure things like timeouts, namespaces, lists of allowed registries, api endpoints or base urls, service account names to use, etc...

Method to Implement	Description
GetConfigName	Use this method to return the name of the configmap admins will use to configure this resolver. Once this interface is implemented your Validate and Resolve methods will be able to access your latest resolver configuration by calling framework.GetResolverConfigFromContext(ctx). Note that this configmap must exist when your resolver starts - put a default one in your resolver's config/ directory.

The TimedResolution Interface

Implement this optional interface if your Resolver needs to custimze the timeout a resolution request can take. This may be based on knowledge of the underlying storage (e.g. some git repositories are slower to clone than others) or might be something an admin configures with a configmap.

The default timeout of a request is 1 minute if this interface is not implemented. Note: There is currently a global maximum timeout of 1 minute for all resolution requests to prevent zombie requests remaining in an incomplete state forever.

Method to Implement	Description
GetResolutionTimeout	Return a custom timeout duration from this method to control how long a resolution request to this resolver may take.