package schema import ( "context" "github.com/hashicorp/terraform/tfdiags" "github.com/zclconf/go-cty/cty" "github.com/hashicorp/terraform/config/configschema" "github.com/hashicorp/terraform/config/hcl2shim" "github.com/hashicorp/terraform/terraform" ) // Backend represents a partial backend.Backend implementation and simplifies // the creation of configuration loading and validation. // // Unlike other schema structs such as Provider, this struct is meant to be // embedded within your actual implementation. It provides implementations // only for Input and Configure and gives you a method for accessing the // configuration in the form of a ResourceData that you're expected to call // from the other implementation funcs. type Backend struct { // Schema is the schema for the configuration of this backend. If this // Backend has no configuration this can be omitted. Schema map[string]*Schema // ConfigureFunc is called to configure the backend. Use the // FromContext* methods to extract information from the context. // This can be nil, in which case nothing will be called but the // config will still be stored. ConfigureFunc func(context.Context) error config *ResourceData } var ( backendConfigKey = contextKey("backend config") ) // FromContextBackendConfig extracts a ResourceData with the configuration // from the context. This should only be called by Backend functions. func FromContextBackendConfig(ctx context.Context) *ResourceData { return ctx.Value(backendConfigKey).(*ResourceData) } func (b *Backend) ConfigSchema() *configschema.Block { // This is an alias of CoreConfigSchema just to implement the // backend.Backend interface. return b.CoreConfigSchema() } func (b *Backend) ValidateConfig(obj cty.Value) tfdiags.Diagnostics { if b == nil { return nil } var diags tfdiags.Diagnostics shimRC := b.shimConfig(obj) warns, errs := schemaMap(b.Schema).Validate(shimRC) for _, warn := range warns { diags = diags.Append(tfdiags.SimpleWarning(warn)) } for _, err := range errs { diags = diags.Append(err) } return diags } func (b *Backend) Configure(obj cty.Value) tfdiags.Diagnostics { if b == nil { return nil } var diags tfdiags.Diagnostics sm := schemaMap(b.Schema) shimRC := b.shimConfig(obj) // Get a ResourceData for this configuration. To do this, we actually // generate an intermediary "diff" although that is never exposed. diff, err := sm.Diff(nil, shimRC, nil, nil) if err != nil { diags = diags.Append(err) return diags } data, err := sm.Data(nil, diff) if err != nil { diags = diags.Append(err) return diags } b.config = data if b.ConfigureFunc != nil { err = b.ConfigureFunc(context.WithValue( context.Background(), backendConfigKey, data)) if err != nil { diags = diags.Append(err) return diags } } return diags } // shimConfig turns a new-style cty.Value configuration (which must be of // an object type) into a minimal old-style *terraform.ResourceConfig object // that should be populated enough to appease the not-yet-updated functionality // in this package. This should be removed once everything is updated. func (b *Backend) shimConfig(obj cty.Value) *terraform.ResourceConfig { shimMap := hcl2shim.ConfigValueFromHCL2(obj).(map[string]interface{}) return &terraform.ResourceConfig{ Config: shimMap, Raw: shimMap, } } // Config returns the configuration. This is available after Configure is // called. func (b *Backend) Config() *ResourceData { return b.config }