554 lines
18 KiB
Go
554 lines
18 KiB
Go
package command
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import (
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"context"
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"errors"
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"path/filepath"
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"sort"
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"strings"
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"github.com/hashicorp/terraform/backend"
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"github.com/hashicorp/terraform/command/clistate"
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"github.com/hashicorp/terraform/state"
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"github.com/hashicorp/terraform/states"
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"github.com/hashicorp/terraform/states/statemgr"
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"github.com/hashicorp/terraform/terraform"
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)
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type backendMigrateOpts struct {
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OneType, TwoType string
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One, Two backend.Backend
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// Fields below are set internally when migrate is called
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oneEnv string // source env
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twoEnv string // dest env
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force bool // if true, won't ask for confirmation
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}
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// backendMigrateState handles migrating (copying) state from one backend
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// to another. This function handles asking the user for confirmation
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// as well as the copy itself.
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//
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// This function can handle all scenarios of state migration regardless
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// of the existence of state in either backend.
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//
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// After migrating the state, the existing state in the first backend
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// remains untouched.
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//
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// This will attempt to lock both states for the migration.
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func (m *Meta) backendMigrateState(opts *backendMigrateOpts) error {
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log.Printf("[TRACE] backendMigrateState: need to migrate from %q to %q backend config", opts.OneType, opts.TwoType)
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// We need to check what the named state status is. If we're converting
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// from multi-state to single-state for example, we need to handle that.
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var oneSingle, twoSingle bool
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oneStates, err := opts.One.Workspaces()
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if err == backend.ErrWorkspacesNotSupported {
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oneSingle = true
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err = nil
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}
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if err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateLoadStates), opts.OneType, err)
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}
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_, err = opts.Two.Workspaces()
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if err == backend.ErrWorkspacesNotSupported {
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twoSingle = true
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err = nil
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}
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if err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateLoadStates), opts.TwoType, err)
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}
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// Setup defaults
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opts.oneEnv = backend.DefaultStateName
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opts.twoEnv = backend.DefaultStateName
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opts.force = m.forceInitCopy
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// Determine migration behavior based on whether the source/destination
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// supports multi-state.
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switch {
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// Single-state to single-state. This is the easiest case: we just
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// copy the default state directly.
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case oneSingle && twoSingle:
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return m.backendMigrateState_s_s(opts)
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// Single-state to multi-state. This is easy since we just copy
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// the default state and ignore the rest in the destination.
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case oneSingle && !twoSingle:
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return m.backendMigrateState_s_s(opts)
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// Multi-state to single-state. If the source has more than the default
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// state this is complicated since we have to ask the user what to do.
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case !oneSingle && twoSingle:
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// If the source only has one state and it is the default,
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// treat it as if it doesn't support multi-state.
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if len(oneStates) == 1 && oneStates[0] == backend.DefaultStateName {
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return m.backendMigrateState_s_s(opts)
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}
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return m.backendMigrateState_S_s(opts)
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// Multi-state to multi-state. We merge the states together (migrating
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// each from the source to the destination one by one).
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case !oneSingle && !twoSingle:
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// If the source only has one state and it is the default,
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// treat it as if it doesn't support multi-state.
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if len(oneStates) == 1 && oneStates[0] == backend.DefaultStateName {
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return m.backendMigrateState_s_s(opts)
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}
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return m.backendMigrateState_S_S(opts)
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}
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return nil
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}
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//-------------------------------------------------------------------
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// State Migration Scenarios
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//
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// The functions below cover handling all the various scenarios that
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// can exist when migrating state. They are named in an immediately not
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// obvious format but is simple:
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//
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// Format: backendMigrateState_s1_s2[_suffix]
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//
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// When s1 or s2 is lower case, it means that it is a single state backend.
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// When either is uppercase, it means that state is a multi-state backend.
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// The suffix is used to disambiguate multiple cases with the same type of
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// states.
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//
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//-------------------------------------------------------------------
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// Multi-state to multi-state.
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func (m *Meta) backendMigrateState_S_S(opts *backendMigrateOpts) error {
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log.Print("[TRACE] backendMigrateState: migrating all named workspaces")
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// Ask the user if they want to migrate their existing remote state
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migrate, err := m.confirm(&terraform.InputOpts{
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Id: "backend-migrate-multistate-to-multistate",
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Query: fmt.Sprintf(
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"Do you want to migrate all workspaces to %q?",
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opts.TwoType),
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Description: fmt.Sprintf(
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strings.TrimSpace(inputBackendMigrateMultiToMulti),
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opts.OneType, opts.TwoType),
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})
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if err != nil {
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return fmt.Errorf(
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"Error asking for state migration action: %s", err)
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}
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if !migrate {
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return fmt.Errorf("Migration aborted by user.")
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}
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// Read all the states
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oneStates, err := opts.One.Workspaces()
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if err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateLoadStates), opts.OneType, err)
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}
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// Sort the states so they're always copied alphabetically
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sort.Strings(oneStates)
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// Go through each and migrate
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for _, name := range oneStates {
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// Copy the same names
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opts.oneEnv = name
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opts.twoEnv = name
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// Force it, we confirmed above
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opts.force = true
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// Perform the migration
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if err := m.backendMigrateState_s_s(opts); err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateMulti), name, opts.OneType, opts.TwoType, err)
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}
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}
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return nil
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}
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// Multi-state to single state.
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func (m *Meta) backendMigrateState_S_s(opts *backendMigrateOpts) error {
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log.Printf("[TRACE] backendMigrateState: target backend type %q does not support named workspaces", opts.TwoType)
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currentEnv := m.Workspace()
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migrate := opts.force
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if !migrate {
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var err error
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// Ask the user if they want to migrate their existing remote state
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migrate, err = m.confirm(&terraform.InputOpts{
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Id: "backend-migrate-multistate-to-single",
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Query: fmt.Sprintf(
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"Destination state %q doesn't support workspaces.\n"+
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"Do you want to copy only your current workspace?",
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opts.TwoType),
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Description: fmt.Sprintf(
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strings.TrimSpace(inputBackendMigrateMultiToSingle),
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opts.OneType, opts.TwoType, currentEnv),
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})
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if err != nil {
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return fmt.Errorf(
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"Error asking for state migration action: %s", err)
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}
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}
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if !migrate {
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return fmt.Errorf("Migration aborted by user.")
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}
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// Copy the default state
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opts.oneEnv = currentEnv
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// now switch back to the default env so we can acccess the new backend
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m.SetWorkspace(backend.DefaultStateName)
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return m.backendMigrateState_s_s(opts)
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}
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// Single state to single state, assumed default state name.
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func (m *Meta) backendMigrateState_s_s(opts *backendMigrateOpts) error {
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log.Printf("[TRACE] backendMigrateState: migrating %q workspace to %q workspace", opts.oneEnv, opts.twoEnv)
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stateOne, err := opts.One.StateMgr(opts.oneEnv)
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if err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.OneType, err)
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}
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if err := stateOne.RefreshState(); err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.OneType, err)
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}
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// Do not migrate workspaces without state.
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if stateOne.State().Empty() {
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log.Print("[TRACE] backendMigrateState: source workspace has empty state, so nothing to migrate")
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return nil
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}
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stateTwo, err := opts.Two.StateMgr(opts.twoEnv)
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if err == backend.ErrDefaultWorkspaceNotSupported {
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// If the backend doesn't support using the default state, we ask the user
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// for a new name and migrate the default state to the given named state.
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stateTwo, err = func() (statemgr.Full, error) {
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log.Print("[TRACE] backendMigrateState: target doesn't support a default workspace, so we must prompt for a new name")
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name, err := m.UIInput().Input(&terraform.InputOpts{
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Id: "new-state-name",
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Query: fmt.Sprintf(
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"[reset][bold][yellow]The %q backend configuration only allows "+
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"named workspaces![reset]",
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opts.TwoType),
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Description: strings.TrimSpace(inputBackendNewWorkspaceName),
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})
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if err != nil {
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return nil, fmt.Errorf("Error asking for new state name: %s", err)
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}
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// Update the name of the target state.
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opts.twoEnv = name
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stateTwo, err := opts.Two.StateMgr(opts.twoEnv)
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if err != nil {
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return nil, err
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}
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// If the currently selected workspace is the default workspace, then set
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// the named workspace as the new selected workspace.
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if m.Workspace() == backend.DefaultStateName {
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if err := m.SetWorkspace(opts.twoEnv); err != nil {
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return nil, fmt.Errorf("Failed to set new workspace: %s", err)
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}
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}
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return stateTwo, nil
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}()
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}
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if err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.TwoType, err)
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}
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if err := stateTwo.RefreshState(); err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.TwoType, err)
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}
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// Check if we need migration at all.
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// This is before taking a lock, because they may also correspond to the same lock.
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one := stateOne.State()
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two := stateTwo.State()
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// no reason to migrate if the state is already there
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if one.Equal(two) {
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// Equal isn't identical; it doesn't check lineage.
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sm1, _ := stateOne.(statemgr.PersistentMeta)
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sm2, _ := stateTwo.(statemgr.PersistentMeta)
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if one != nil && two != nil {
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if sm1 == nil || sm2 == nil {
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log.Print("[TRACE] backendMigrateState: both source and destination workspaces have no state, so no migration is needed")
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return nil
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}
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if sm1.StateSnapshotMeta().Lineage == sm2.StateSnapshotMeta().Lineage {
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log.Printf("[TRACE] backendMigrateState: both source and destination workspaces have equal state with lineage %q, so no migration is needed", sm1.StateSnapshotMeta().Lineage)
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return nil
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}
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}
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}
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if m.stateLock {
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lockCtx := context.Background()
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lockerOne := clistate.NewLocker(lockCtx, m.stateLockTimeout, m.Ui, m.Colorize())
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if err := lockerOne.Lock(stateOne, "migration source state"); err != nil {
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return fmt.Errorf("Error locking source state: %s", err)
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}
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defer lockerOne.Unlock(nil)
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lockerTwo := clistate.NewLocker(lockCtx, m.stateLockTimeout, m.Ui, m.Colorize())
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if err := lockerTwo.Lock(stateTwo, "migration destination state"); err != nil {
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return fmt.Errorf("Error locking destination state: %s", err)
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}
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defer lockerTwo.Unlock(nil)
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// We now own a lock, so double check that we have the version
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// corresponding to the lock.
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log.Print("[TRACE] backendMigrateState: refreshing source workspace state")
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if err := stateOne.RefreshState(); err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.OneType, err)
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}
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log.Print("[TRACE] backendMigrateState: refreshing target workspace state")
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if err := stateTwo.RefreshState(); err != nil {
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return fmt.Errorf(strings.TrimSpace(
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errMigrateSingleLoadDefault), opts.OneType, err)
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}
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one = stateOne.State()
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two = stateTwo.State()
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}
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var confirmFunc func(state.State, state.State, *backendMigrateOpts) (bool, error)
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switch {
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// No migration necessary
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case one.Empty() && two.Empty():
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log.Print("[TRACE] backendMigrateState: both source and destination workspaces have empty state, so no migration is required")
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return nil
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// No migration necessary if we're inheriting state.
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case one.Empty() && !two.Empty():
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log.Print("[TRACE] backendMigrateState: source workspace has empty state, so no migration is required")
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return nil
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// We have existing state moving into no state. Ask the user if
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// they'd like to do this.
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case !one.Empty() && two.Empty():
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log.Print("[TRACE] backendMigrateState: target workspace has empty state, so might copy source workspace state")
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confirmFunc = m.backendMigrateEmptyConfirm
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// Both states are non-empty, meaning we need to determine which
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// state should be used and update accordingly.
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case !one.Empty() && !two.Empty():
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log.Print("[TRACE] backendMigrateState: both source and destination workspaces have states, so might overwrite destination with source")
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confirmFunc = m.backendMigrateNonEmptyConfirm
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}
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if confirmFunc == nil {
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panic("confirmFunc must not be nil")
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}
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if !opts.force {
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// Abort if we can't ask for input.
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if !m.input {
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log.Print("[TRACE] backendMigrateState: can't prompt for input, so aborting migration")
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return errors.New("error asking for state migration action: input disabled")
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}
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// Confirm with the user whether we want to copy state over
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confirm, err := confirmFunc(stateOne, stateTwo, opts)
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if err != nil {
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return err
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}
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if !confirm {
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return nil
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}
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}
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// Confirmed! We'll have the statemgr package handle the migration, which
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// includes preserving any lineage/serial information where possible, if
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// both managers support such metadata.
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if err := statemgr.Migrate(stateTwo, stateOne); err != nil {
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return fmt.Errorf(strings.TrimSpace(errBackendStateCopy),
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opts.OneType, opts.TwoType, err)
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}
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if err := stateTwo.PersistState(); err != nil {
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return fmt.Errorf(strings.TrimSpace(errBackendStateCopy),
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opts.OneType, opts.TwoType, err)
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}
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// And we're done.
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return nil
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}
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func (m *Meta) backendMigrateEmptyConfirm(one, two state.State, opts *backendMigrateOpts) (bool, error) {
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inputOpts := &terraform.InputOpts{
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Id: "backend-migrate-copy-to-empty",
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Query: "Do you want to copy existing state to the new backend?",
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Description: fmt.Sprintf(
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strings.TrimSpace(inputBackendMigrateEmpty),
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opts.OneType, opts.TwoType),
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}
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return m.confirm(inputOpts)
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}
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func (m *Meta) backendMigrateNonEmptyConfirm(
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stateOne, stateTwo state.State, opts *backendMigrateOpts) (bool, error) {
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// We need to grab both states so we can write them to a file
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one := stateOne.State()
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two := stateTwo.State()
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// Save both to a temporary
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td, err := ioutil.TempDir("", "terraform")
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if err != nil {
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return false, fmt.Errorf("Error creating temporary directory: %s", err)
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}
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defer os.RemoveAll(td)
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// Helper to write the state
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saveHelper := func(n, path string, s *states.State) error {
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mgr := statemgr.NewFilesystem(path)
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return mgr.WriteState(s)
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}
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// Write the states
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onePath := filepath.Join(td, fmt.Sprintf("1-%s.tfstate", opts.OneType))
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twoPath := filepath.Join(td, fmt.Sprintf("2-%s.tfstate", opts.TwoType))
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if err := saveHelper(opts.OneType, onePath, one); err != nil {
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return false, fmt.Errorf("Error saving temporary state: %s", err)
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}
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if err := saveHelper(opts.TwoType, twoPath, two); err != nil {
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return false, fmt.Errorf("Error saving temporary state: %s", err)
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}
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// Ask for confirmation
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inputOpts := &terraform.InputOpts{
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Id: "backend-migrate-to-backend",
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Query: "Do you want to copy existing state to the new backend?",
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Description: fmt.Sprintf(
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strings.TrimSpace(inputBackendMigrateNonEmpty),
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opts.OneType, opts.TwoType, onePath, twoPath),
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}
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// Confirm with the user that the copy should occur
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return m.confirm(inputOpts)
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}
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const errMigrateLoadStates = `
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Error inspecting states in the %q backend:
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%s
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Prior to changing backends, Terraform inspects the source and destination
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states to determine what kind of migration steps need to be taken, if any.
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Terraform failed to load the states. The data in both the source and the
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destination remain unmodified. Please resolve the above error and try again.
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`
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const errMigrateSingleLoadDefault = `
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Error loading state:
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%[2]s
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Terraform failed to load the default state from the %[1]q backend.
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State migration cannot occur unless the state can be loaded. Backend
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modification and state migration has been aborted. The state in both the
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source and the destination remain unmodified. Please resolve the
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above error and try again.
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`
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const errMigrateMulti = `
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Error migrating the workspace %q from the previous %q backend
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to the newly configured %q backend:
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%s
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Terraform copies workspaces in alphabetical order. Any workspaces
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alphabetically earlier than this one have been copied. Any workspaces
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later than this haven't been modified in the destination. No workspaces
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in the source state have been modified.
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Please resolve the error above and run the initialization command again.
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This will attempt to copy (with permission) all workspaces again.
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`
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const errBackendStateCopy = `
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Error copying state from the previous %q backend to the newly configured
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%q backend:
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%s
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The state in the previous backend remains intact and unmodified. Please resolve
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the error above and try again.
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`
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const inputBackendMigrateEmpty = `
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Pre-existing state was found while migrating the previous %q backend to the
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newly configured %q backend. No existing state was found in the newly
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configured %[2]q backend. Do you want to copy this state to the new %[2]q
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backend? Enter "yes" to copy and "no" to start with an empty state.
|
|
`
|
|
|
|
const inputBackendMigrateNonEmpty = `
|
|
Pre-existing state was found while migrating the previous %q backend to the
|
|
newly configured %q backend. An existing non-empty state already exists in
|
|
the new backend. The two states have been saved to temporary files that will be
|
|
removed after responding to this query.
|
|
|
|
Previous (type %[1]q): %[3]s
|
|
New (type %[2]q): %[4]s
|
|
|
|
Do you want to overwrite the state in the new backend with the previous state?
|
|
Enter "yes" to copy and "no" to start with the existing state in the newly
|
|
configured %[2]q backend.
|
|
`
|
|
|
|
const inputBackendMigrateMultiToSingle = `
|
|
The existing %[1]q backend supports workspaces and you currently are
|
|
using more than one. The newly configured %[2]q backend doesn't support
|
|
workspaces. If you continue, Terraform will copy your current workspace %[3]q
|
|
to the default workspace in the target backend. Your existing workspaces in the
|
|
source backend won't be modified. If you want to switch workspaces, back them
|
|
up, or cancel altogether, answer "no" and Terraform will abort.
|
|
`
|
|
|
|
const inputBackendMigrateMultiToMulti = `
|
|
Both the existing %[1]q backend and the newly configured %[2]q backend
|
|
support workspaces. When migrating between backends, Terraform will copy
|
|
all workspaces (with the same names). THIS WILL OVERWRITE any conflicting
|
|
states in the destination.
|
|
|
|
Terraform initialization doesn't currently migrate only select workspaces.
|
|
If you want to migrate a select number of workspaces, you must manually
|
|
pull and push those states.
|
|
|
|
If you answer "yes", Terraform will migrate all states. If you answer
|
|
"no", Terraform will abort.
|
|
`
|
|
|
|
const inputBackendNewWorkspaceName = `
|
|
Please provide a new workspace name (e.g. dev, test) that will be used
|
|
to migrate the existing default workspace.
|
|
`
|
|
|
|
const inputBackendSelectWorkspace = `
|
|
This is expected behavior when the selected workspace did not have an
|
|
existing non-empty state. Please enter a number to select a workspace:
|
|
|
|
%s
|
|
`
|