terraform/helper/schema/resource.go

165 lines
4.6 KiB
Go

package schema
import (
"errors"
"fmt"
"github.com/hashicorp/terraform/terraform"
)
// Resource represents a thing in Terraform that has a set of configurable
// attributes and a lifecycle (create, read, update, delete).
//
// The Resource schema is an abstraction that allows provider writers to
// worry only about CRUD operations while off-loading validation, diff
// generation, etc. to this higher level library.
type Resource struct {
// Schema is the schema for the configuration of this resource.
//
// The keys of this map are the configuration keys, and the values
// describe the schema of the configuration value.
//
// The schema is used to represent both configurable data as well
// as data that might be computed in the process of creating this
// resource.
Schema map[string]*Schema
// The functions below are the CRUD operations for this resource.
//
// The only optional operation is Update. If Update is not implemented,
// then updates will not be supported for this resource.
//
// The ResourceData parameter in the functions below are used to
// query configuration and changes for the resource as well as to set
// the ID, computed data, etc.
//
// The interface{} parameter is the result of the ConfigureFunc in
// the provider for this resource. If the provider does not define
// a ConfigureFunc, this will be nil. This parameter should be used
// to store API clients, configuration structures, etc.
//
// If any errors occur during each of the operation, an error should be
// returned. If a resource was partially updated, be careful to enable
// partial state mode for ResourceData and use it accordingly.
Create CreateFunc
Read ReadFunc
Update UpdateFunc
Delete DeleteFunc
}
// See Resource documentation.
type CreateFunc func(*ResourceData, interface{}) error
// See Resource documentation.
type ReadFunc func(*ResourceData, interface{}) error
// See Resource documentation.
type UpdateFunc func(*ResourceData, interface{}) error
// See Resource documentation.
type DeleteFunc func(*ResourceData, interface{}) error
// Apply creates, updates, and/or deletes a resource.
func (r *Resource) Apply(
s *terraform.InstanceState,
d *terraform.InstanceDiff,
meta interface{}) (*terraform.InstanceState, error) {
data, err := schemaMap(r.Schema).Data(s, d)
if err != nil {
return s, err
}
if s == nil {
// The Terraform API dictates that this should never happen, but
// it doesn't hurt to be safe in this case.
s = new(terraform.InstanceState)
}
if d.Destroy || d.RequiresNew() {
if s.ID != "" {
// Destroy the resource since it is created
if err := r.Delete(data, meta); err != nil {
return data.State(), err
}
// Make sure the ID is gone.
data.SetId("")
}
// If we're only destroying, and not creating, then return
// now since we're done!
if !d.RequiresNew() {
return nil, nil
}
// Reset the data to be stateless since we just destroyed
data, err = schemaMap(r.Schema).Data(nil, d)
if err != nil {
return nil, err
}
}
err = nil
if data.Id() == "" {
// We're creating, it is a new resource.
err = r.Create(data, meta)
} else {
if r.Update == nil {
return s, fmt.Errorf("doesn't support update")
}
err = r.Update(data, meta)
}
return data.State(), err
}
// Diff returns a diff of this resource and is API compatible with the
// ResourceProvider interface.
func (r *Resource) Diff(
s *terraform.InstanceState,
c *terraform.ResourceConfig) (*terraform.InstanceDiff, error) {
return schemaMap(r.Schema).Diff(s, c)
}
// Validate validates the resource configuration against the schema.
func (r *Resource) Validate(c *terraform.ResourceConfig) ([]string, []error) {
return schemaMap(r.Schema).Validate(c)
}
// Refresh refreshes the state of the resource.
func (r *Resource) Refresh(
s *terraform.InstanceState,
meta interface{}) (*terraform.InstanceState, error) {
data, err := schemaMap(r.Schema).Data(s, nil)
if err != nil {
return s, err
}
err = r.Read(data, meta)
state := data.State()
if state != nil && state.ID == "" {
state = nil
}
return state, err
}
// InternalValidate should be called to validate the structure
// of the resource.
//
// This should be called in a unit test for any resource to verify
// before release that a resource is properly configured for use with
// this library.
//
// Provider.InternalValidate() will automatically call this for all of
// the resources it manages, so you don't need to call this manually if it
// is part of a Provider.
func (r *Resource) InternalValidate() error {
if r == nil {
return errors.New("resource is nil")
}
return schemaMap(r.Schema).InternalValidate()
}