terraform/backend/local/backend.go

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package local
import (
"context"
"fmt"
"sync"
"github.com/hashicorp/errwrap"
"github.com/hashicorp/terraform/backend"
"github.com/hashicorp/terraform/helper/schema"
"github.com/hashicorp/terraform/state"
"github.com/hashicorp/terraform/terraform"
"github.com/mitchellh/cli"
"github.com/mitchellh/colorstring"
)
// Local is an implementation of EnhancedBackend that performs all operations
// locally. This is the "default" backend and implements normal Terraform
// behavior as it is well known.
type Local struct {
// CLI and Colorize control the CLI output. If CLI is nil then no CLI
// output will be done. If CLIColor is nil then no coloring will be done.
CLI cli.Ui
CLIColor *colorstring.Colorize
// StatePath is the local path where state is read from.
//
// StateOutPath is the local path where the state will be written.
// If this is empty, it will default to StatePath.
//
// StateBackupPath is the local path where a backup file will be written.
// If this is empty, no backup will be taken.
StatePath string
StateOutPath string
StateBackupPath string
// we only want to create a single instance of the local state
state state.State
// ContextOpts are the base context options to set when initializing a
// Terraform context. Many of these will be overridden or merged by
// Operation. See Operation for more details.
ContextOpts *terraform.ContextOpts
// OpInput will ask for necessary input prior to performing any operations.
//
// OpValidation will perform validation prior to running an operation. The
// variable naming doesn't match the style of others since we have a func
// Validate.
OpInput bool
OpValidation bool
// Backend, if non-nil, will use this backend for non-enhanced behavior.
// This allows local behavior with remote state storage. It is a way to
// "upgrade" a non-enhanced backend to an enhanced backend with typical
// behavior.
//
// If this is nil, local performs normal state loading and storage.
Backend backend.Backend
schema *schema.Backend
opLock sync.Mutex
once sync.Once
}
func (b *Local) Input(
ui terraform.UIInput, c *terraform.ResourceConfig) (*terraform.ResourceConfig, error) {
b.once.Do(b.init)
f := b.schema.Input
if b.Backend != nil {
f = b.Backend.Input
}
return f(ui, c)
}
func (b *Local) Validate(c *terraform.ResourceConfig) ([]string, []error) {
b.once.Do(b.init)
f := b.schema.Validate
if b.Backend != nil {
f = b.Backend.Validate
}
return f(c)
}
func (b *Local) Configure(c *terraform.ResourceConfig) error {
b.once.Do(b.init)
f := b.schema.Configure
if b.Backend != nil {
f = b.Backend.Configure
}
return f(c)
}
func (b *Local) State() (state.State, error) {
// If we have a backend handling state, defer to that.
if b.Backend != nil {
return b.Backend.State()
}
if b.state != nil {
return b.state, nil
}
// Otherwise, we need to load the state.
var s state.State = &state.LocalState{
Path: b.StatePath,
PathOut: b.StateOutPath,
}
// Load the state as a sanity check
if err := s.RefreshState(); err != nil {
return nil, errwrap.Wrapf("Error reading local state: {{err}}", err)
}
// If we are backing up the state, wrap it
if path := b.StateBackupPath; path != "" {
s = &state.BackupState{
Real: s,
Path: path,
}
}
b.state = s
return s, nil
}
// Operation implements backend.Enhanced
//
// This will initialize an in-memory terraform.Context to perform the
// operation within this process.
//
// The given operation parameter will be merged with the ContextOpts on
// the structure with the following rules. If a rule isn't specified and the
// name conflicts, assume that the field is overwritten if set.
func (b *Local) Operation(ctx context.Context, op *backend.Operation) (*backend.RunningOperation, error) {
// Determine the function to call for our operation
var f func(context.Context, *backend.Operation, *backend.RunningOperation)
switch op.Type {
case backend.OperationTypeRefresh:
f = b.opRefresh
case backend.OperationTypePlan:
f = b.opPlan
case backend.OperationTypeApply:
f = b.opApply
default:
return nil, fmt.Errorf(
"Unsupported operation type: %s\n\n"+
"This is a bug in Terraform and should be reported. The local backend\n"+
"is built-in to Terraform and should always support all operations.",
op.Type)
}
// Lock
b.opLock.Lock()
// Build our running operation
runningCtx, runningCtxCancel := context.WithCancel(context.Background())
runningOp := &backend.RunningOperation{Context: runningCtx}
// Do it
go func() {
defer b.opLock.Unlock()
defer runningCtxCancel()
f(ctx, op, runningOp)
}()
// Return
return runningOp, nil
}
// Colorize returns the Colorize structure that can be used for colorizing
// output. This is gauranteed to always return a non-nil value and so is useful
// as a helper to wrap any potentially colored strings.
func (b *Local) Colorize() *colorstring.Colorize {
if b.CLIColor != nil {
return b.CLIColor
}
return &colorstring.Colorize{
Colors: colorstring.DefaultColors,
Disable: true,
}
}
func (b *Local) init() {
b.schema = &schema.Backend{
Schema: map[string]*schema.Schema{
"path": &schema.Schema{
Type: schema.TypeString,
Optional: true,
},
},
ConfigureFunc: b.schemaConfigure,
}
}
func (b *Local) schemaConfigure(ctx context.Context) error {
d := schema.FromContextBackendConfig(ctx)
// Set the path if it is set
pathRaw, ok := d.GetOk("path")
if ok {
path := pathRaw.(string)
if path == "" {
return fmt.Errorf("configured path is empty")
}
b.StatePath = path
}
return nil
}