From 594a821ab306bd526e2f86981cdcdaf19a711cc6 Mon Sep 17 00:00:00 2001 From: Martin Atkins Date: Wed, 15 Aug 2018 12:09:09 -0700 Subject: [PATCH] providers: Resolver and Factory types These new types are adaptations of terraform.ProviderResolver and terraform.ResourceProviderFactory respectively. In a later commit we will update users of the old types to use these new types, possibly in a "gradual repair" sort of fashion by initially using type aliases, though that won't 100% solve the problem because the types themselves have changed in this move to return providers.Interface instead of terraform.ResourceProvider. --- providers/resolver.go | 112 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 providers/resolver.go diff --git a/providers/resolver.go b/providers/resolver.go new file mode 100644 index 000000000..4de8e0acd --- /dev/null +++ b/providers/resolver.go @@ -0,0 +1,112 @@ +package providers + +import ( + "fmt" + + "github.com/hashicorp/terraform/plugin/discovery" +) + +// Resolver is an interface implemented by objects that are able to resolve +// a given set of resource provider version constraints into Factory +// callbacks. +type Resolver interface { + // Given a constraint map, return a Factory for each requested provider. + // If some or all of the constraints cannot be satisfied, return a non-nil + // slice of errors describing the problems. + ResolveProviders(reqd discovery.PluginRequirements) (map[string]Factory, []error) +} + +// ResolverFunc wraps a callback function and turns it into a Resolver +// implementation, for convenience in situations where a function and its +// associated closure are sufficient as a resolver implementation. +type ResolverFunc func(reqd discovery.PluginRequirements) (map[string]Factory, []error) + +// ResolveProviders implements Resolver by calling the +// wrapped function. +func (f ResolverFunc) ResolveProviders(reqd discovery.PluginRequirements) (map[string]Factory, []error) { + return f(reqd) +} + +// ResolverFixed returns a Resolver that has a fixed set of provider factories +// provided by the caller. The returned resolver ignores version constraints +// entirely and just returns the given factory for each requested provider +// name. +// +// This function is primarily used in tests, to provide mock providers or +// in-process providers under test. +func ResolverFixed(factories map[string]Factory) Resolver { + return ResolverFunc(func(reqd discovery.PluginRequirements) (map[string]Factory, []error) { + ret := make(map[string]Factory, len(reqd)) + var errs []error + for name := range reqd { + if factory, exists := factories[name]; exists { + ret[name] = factory + } else { + errs = append(errs, fmt.Errorf("provider %q is not available", name)) + } + } + return ret, errs + }) +} + +// Factory is a function type that creates a new instance of a resource +// provider, or returns an error if that is impossible. +type Factory func() (Interface, error) + +// FactoryFixed is a helper that creates a Factory that just returns some given +// single provider. +// +// Unlike usual factories, the exact same instance is returned for each call +// to the factory and so this must be used in only specialized situations where +// the caller can take care to either not mutate the given provider at all +// or to mutate it in ways that will not cause unexpected behavior for others +// holding the same reference. +func FactoryFixed(p Interface) Factory { + return func() (Interface, error) { + return p, nil + } +} + +// ProviderHasResource is a helper that requests schema from the given provider +// and checks if it has a resource type of the given name. +// +// This function is more expensive than it may first appear since it must +// retrieve the entire schema from the underlying provider, and so it should +// be used sparingly and especially not in tight loops. +// +// Since retrieving the provider may fail (e.g. if the provider is accessed +// over an RPC channel that has operational problems), this function will +// return false if the schema cannot be retrieved, under the assumption that +// a subsequent call to do anything with the resource type would fail +// anyway. +func ProviderHasResource(provider Interface, typeName string) bool { + resp := provider.GetSchema() + if resp.Diagnostics.HasErrors() { + return false + } + + _, exists := resp.ResourceTypes[typeName] + return exists +} + +// ProviderHasDataSource is a helper that requests schema from the given +// provider and checks if it has a data source of the given name. +// +// This function is more expensive than it may first appear since it must +// retrieve the entire schema from the underlying provider, and so it should +// be used sparingly and especially not in tight loops. +// +// Since retrieving the provider may fail (e.g. if the provider is accessed +// over an RPC channel that has operational problems), this function will +// return false if the schema cannot be retrieved, under the assumption that +// a subsequent call to do anything with the data source would fail +// anyway. +func ProviderHasDataSource(provider Interface, dataSourceName string) bool { + resp := provider.GetSchema() + if resp.Diagnostics.HasErrors() { + return false + } + + _, exists := resp.DataSources[dataSourceName] + return exists +}