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|
package statefile
import (
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
version "github.com/hashicorp/go-version"
"github.com/hashicorp/terraform/tfdiags"
tfversion "github.com/hashicorp/terraform/version"
)
// ErrNoState is returned by ReadState when the state file is empty.
var ErrNoState = errors.New("no state")
// Read reads a state from the given reader.
//
// Legacy state format versions 1 through 3 are supported, but the result will
// contain object attributes in the deprecated "flatmap" format and so must
// be upgraded by the caller before use.
//
// If the state file is empty, the special error value ErrNoState is returned.
// Otherwise, the returned error might be a wrapper around tfdiags.Diagnostics
// potentially describing multiple errors.
func Read(r io.Reader) (*File, error) {
// Some callers provide us a "typed nil" *os.File here, which would
// cause us to panic below if we tried to use it.
if f, ok := r.(*os.File); ok && f == nil {
return nil, ErrNoState
}
var diags tfdiags.Diagnostics
// We actually just buffer the whole thing in memory, because states are
// generally not huge and we need to do be able to sniff for a version
// number before full parsing.
src, err := ioutil.ReadAll(r)
if err != nil {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
"Failed to read state file",
fmt.Sprintf("The state file could not be read: %s", err),
))
return nil, diags.Err()
}
if len(src) == 0 {
return nil, ErrNoState
}
state, diags := readState(src)
if diags.HasErrors() {
return nil, diags.Err()
}
if state == nil {
// Should never happen
panic("readState returned nil state with no errors")
}
if state.TerraformVersion != nil && state.TerraformVersion.GreaterThan(tfversion.SemVer) {
return state, fmt.Errorf(
"state snapshot was created by Terraform v%s, which is newer than current v%s; upgrade to Terraform v%s or greater to work with this state",
state.TerraformVersion,
tfversion.SemVer,
state.TerraformVersion,
)
}
return state, diags.Err()
}
func readState(src []byte) (*File, tfdiags.Diagnostics) {
var diags tfdiags.Diagnostics
if looksLikeVersion0(src) {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
"The state is stored in a legacy binary format that is not supported since Terraform v0.7. To continue, first upgrade the state using Terraform 0.6.16 or earlier.",
))
return nil, diags
}
version, versionDiags := sniffJSONStateVersion(src)
diags = diags.Append(versionDiags)
if versionDiags.HasErrors() {
return nil, diags
}
switch version {
case 0:
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
"The state file uses JSON syntax but has a version number of zero. There was never a JSON-based state format zero, so this state file is invalid and cannot be processed.",
))
return nil, diags
case 1:
return readStateV1(src)
case 2:
return readStateV2(src)
case 3:
return readStateV3(src)
case 4:
return readStateV4(src)
default:
thisVersion := tfversion.SemVer.String()
creatingVersion := sniffJSONStateTerraformVersion(src)
switch {
case creatingVersion != "":
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
fmt.Sprintf("The state file uses format version %d, which is not supported by Terraform %s. This state file was created by Terraform %s.", version, thisVersion, creatingVersion),
))
default:
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
fmt.Sprintf("The state file uses format version %d, which is not supported by Terraform %s. This state file may have been created by a newer version of Terraform.", version, thisVersion),
))
}
return nil, diags
}
}
func sniffJSONStateVersion(src []byte) (uint64, tfdiags.Diagnostics) {
var diags tfdiags.Diagnostics
type VersionSniff struct {
Version *uint64 `json:"version"`
}
var sniff VersionSniff
err := json.Unmarshal(src, &sniff)
if err != nil {
switch tErr := err.(type) {
case *json.SyntaxError:
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
fmt.Sprintf("The state file could not be parsed as JSON: syntax error at byte offset %d.", tErr.Offset),
))
case *json.UnmarshalTypeError:
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
fmt.Sprintf("The version in the state file is %s. A positive whole number is required.", tErr.Value),
))
default:
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
"The state file could not be parsed as JSON.",
))
}
}
if sniff.Version == nil {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
unsupportedFormat,
"The state file does not have a \"version\" attribute, which is required to identify the format version.",
))
return 0, diags
}
return *sniff.Version, diags
}
// sniffJSONStateTerraformVersion attempts to sniff the Terraform version
// specification from the given state file source code. The result is either
// a version string or an empty string if no version number could be extracted.
//
// This is a best-effort function intended to produce nicer error messages. It
// should not be used for any real processing.
func sniffJSONStateTerraformVersion(src []byte) string {
type VersionSniff struct {
Version string `json:"terraform_version"`
}
var sniff VersionSniff
err := json.Unmarshal(src, &sniff)
if err != nil {
return ""
}
// Attempt to parse the string as a version so we won't report garbage
// as a version number.
_, err = version.NewVersion(sniff.Version)
if err != nil {
return ""
}
return sniff.Version
}
// unsupportedFormat is a diagnostic summary message for when the state file
// seems to not be a state file at all, or is not a supported version.
//
// Use invalidFormat instead for the subtly-different case of "this looks like
// it's intended to be a state file but it's not structured correctly".
const unsupportedFormat = "Unsupported state file format"
const upgradeFailed = "State format upgrade failed"
|
