137 lines
3.3 KiB
Go
137 lines
3.3 KiB
Go
package remote
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import (
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"bytes"
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"fmt"
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"sync"
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"github.com/hashicorp/terraform/state"
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"github.com/hashicorp/terraform/terraform"
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)
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// State implements the State interfaces in the state package to handle
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// reading and writing the remote state. This State on its own does no
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// local caching so every persist will go to the remote storage and local
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// writes will go to memory.
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type State struct {
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mu sync.Mutex
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Client Client
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state, readState *terraform.State
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}
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// StateReader impl.
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func (s *State) State() *terraform.State {
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s.mu.Lock()
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defer s.mu.Unlock()
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return s.state.DeepCopy()
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}
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// StateWriter impl.
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func (s *State) WriteState(state *terraform.State) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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if s.readState != nil && !state.SameLineage(s.readState) {
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return fmt.Errorf("incompatible state lineage; given %s but want %s", state.Lineage, s.readState.Lineage)
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}
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// We create a deep copy of the state here, because the caller also has
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// a reference to the given object and can potentially go on to mutate
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// it after we return, but we want the snapshot at this point in time.
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s.state = state.DeepCopy()
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// Force our new state to have the same serial as our read state. We'll
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// update this if PersistState is called later. (We don't require nor trust
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// the caller to properly maintain serial for transient state objects since
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// the rest of Terraform treats state as an openly mutable object.)
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//
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// If we have no read state then we assume we're either writing a new
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// state for the first time or we're migrating a state from elsewhere,
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// and in both cases we wish to retain the lineage and serial from
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// the given state.
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if s.readState != nil {
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s.state.Serial = s.readState.Serial
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}
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return nil
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}
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// StateRefresher impl.
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func (s *State) RefreshState() error {
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s.mu.Lock()
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defer s.mu.Unlock()
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payload, err := s.Client.Get()
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if err != nil {
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return err
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}
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// no remote state is OK
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if payload == nil {
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return nil
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}
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state, err := terraform.ReadState(bytes.NewReader(payload.Data))
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if err != nil {
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return err
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}
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s.state = state
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s.readState = s.state.DeepCopy() // our states must be separate instances so we can track changes
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return nil
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}
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// StatePersister impl.
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func (s *State) PersistState() error {
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s.mu.Lock()
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defer s.mu.Unlock()
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if !s.state.MarshalEqual(s.readState) {
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// Our new state does not marshal as byte-for-byte identical to
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// the old, so we need to increment the serial.
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// Note that in WriteState we force the serial to match that of
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// s.readState, if we have a readState.
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s.state.Serial++
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}
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var buf bytes.Buffer
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if err := terraform.WriteState(s.state, &buf); err != nil {
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return err
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}
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err := s.Client.Put(buf.Bytes())
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if err != nil {
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return err
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}
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// After we've successfully persisted, what we just wrote is our new
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// reference state until someone calls RefreshState again.
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s.readState = s.state.DeepCopy()
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return nil
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}
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// Lock calls the Client's Lock method if it's implemented.
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func (s *State) Lock(info *state.LockInfo) (string, error) {
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s.mu.Lock()
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defer s.mu.Unlock()
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if c, ok := s.Client.(ClientLocker); ok {
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return c.Lock(info)
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}
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return "", nil
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}
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// Unlock calls the Client's Unlock method if it's implemented.
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func (s *State) Unlock(id string) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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if c, ok := s.Client.(ClientLocker); ok {
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return c.Unlock(id)
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}
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return nil
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}
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