terraform/terraform/resource_provider.go

185 lines
6.8 KiB
Go

package terraform
// ResourceProvider is an interface that must be implemented by any
// resource provider: the thing that creates and manages the resources in
// a Terraform configuration.
//
// Important implementation note: All returned pointers, such as
// *ResourceConfig, *InstanceState, *InstanceDiff, etc. must not point to
// shared data. Terraform is highly parallel and assumes that this data is safe
// to read/write in parallel so it must be unique references. Note that it is
// safe to return arguments as results, however.
type ResourceProvider interface {
/*********************************************************************
* Functions related to the provider
*********************************************************************/
// Input is called to ask the provider to ask the user for input
// for completing the configuration if necesarry.
//
// This may or may not be called, so resource provider writers shouldn't
// rely on this being available to set some default values for validate
// later. Example of a situation where this wouldn't be called is if
// the user is not using a TTY.
Input(UIInput, *ResourceConfig) (*ResourceConfig, error)
// Validate is called once at the beginning with the raw configuration
// (no interpolation done) and can return a list of warnings and/or
// errors.
//
// This is called once with the provider configuration only. It may not
// be called at all if no provider configuration is given.
//
// This should not assume that any values of the configurations are valid.
// The primary use case of this call is to check that required keys are
// set.
Validate(*ResourceConfig) ([]string, []error)
// Configure configures the provider itself with the configuration
// given. This is useful for setting things like access keys.
//
// This won't be called at all if no provider configuration is given.
//
// Configure returns an error if it occurred.
Configure(*ResourceConfig) error
// Resources returns all the available resource types that this provider
// knows how to manage.
Resources() []ResourceType
/*********************************************************************
* Functions related to individual resources
*********************************************************************/
// ValidateResource is called once at the beginning with the raw
// configuration (no interpolation done) and can return a list of warnings
// and/or errors.
//
// This is called once per resource.
//
// This should not assume any of the values in the resource configuration
// are valid since it is possible they have to be interpolated still.
// The primary use case of this call is to check that the required keys
// are set and that the general structure is correct.
ValidateResource(string, *ResourceConfig) ([]string, []error)
// Apply applies a diff to a specific resource and returns the new
// resource state along with an error.
//
// If the resource state given has an empty ID, then a new resource
// is expected to be created.
Apply(
*InstanceInfo,
*InstanceState,
*InstanceDiff) (*InstanceState, error)
// Diff diffs a resource versus a desired state and returns
// a diff.
Diff(
*InstanceInfo,
*InstanceState,
*ResourceConfig) (*InstanceDiff, error)
// Refresh refreshes a resource and updates all of its attributes
// with the latest information.
Refresh(*InstanceInfo, *InstanceState) (*InstanceState, error)
/*********************************************************************
* Functions related to importing
*********************************************************************/
// ImportState requests that the given resource be imported.
//
// The returned InstanceState only requires ID be set. Importing
// will always call Refresh after the state to complete it.
//
// IMPORTANT: InstanceState doesn't have the resource type attached
// to it. A type must be specified on the state via the Ephemeral
// field on the state.
//
// This function can return multiple states. Normally, an import
// will map 1:1 to a physical resource. However, some resources map
// to multiple. For example, an AWS security group may contain many rules.
// Each rule is represented by a separate resource in Terraform,
// therefore multiple states are returned.
ImportState(*InstanceInfo, string) ([]*InstanceState, error)
/*********************************************************************
* Functions related to data resources
*********************************************************************/
// ValidateDataSource is called once at the beginning with the raw
// configuration (no interpolation done) and can return a list of warnings
// and/or errors.
//
// This is called once per data source instance.
//
// This should not assume any of the values in the resource configuration
// are valid since it is possible they have to be interpolated still.
// The primary use case of this call is to check that the required keys
// are set and that the general structure is correct.
ValidateDataSource(string, *ResourceConfig) ([]string, []error)
// DataSources returns all of the available data sources that this
// provider implements.
DataSources() []DataSource
// ReadDataDiff produces a diff that represents the state that will
// be produced when the given data source is read using a later call
// to ReadDataApply.
ReadDataDiff(*InstanceInfo, *ResourceConfig) (*InstanceDiff, error)
// ReadDataApply initializes a data instance using the configuration
// in a diff produced by ReadDataDiff.
ReadDataApply(*InstanceInfo, *InstanceDiff) (*InstanceState, error)
}
// ResourceProviderCloser is an interface that providers that can close
// connections that aren't needed anymore must implement.
type ResourceProviderCloser interface {
Close() error
}
// ResourceType is a type of resource that a resource provider can manage.
type ResourceType struct {
Name string // Name of the resource, example "instance" (no provider prefix)
Importable bool // Whether this resource supports importing
}
// DataSource is a data source that a resource provider implements.
type DataSource struct {
Name string
}
// ResourceProviderFactory is a function type that creates a new instance
// of a resource provider.
type ResourceProviderFactory func() (ResourceProvider, error)
// ResourceProviderFactoryFixed is a helper that creates a
// ResourceProviderFactory that just returns some fixed provider.
func ResourceProviderFactoryFixed(p ResourceProvider) ResourceProviderFactory {
return func() (ResourceProvider, error) {
return p, nil
}
}
func ProviderHasResource(p ResourceProvider, n string) bool {
for _, rt := range p.Resources() {
if rt.Name == n {
return true
}
}
return false
}
func ProviderHasDataSource(p ResourceProvider, n string) bool {
for _, rt := range p.DataSources() {
if rt.Name == n {
return true
}
}
return false
}