databricks-cli/bundle/deploy/terraform/state_pull.go

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package terraform
import (
"context"
"encoding/json"
"errors"
"io"
"io/fs"
"os"
"path/filepath"
"github.com/databricks/cli/bundle"
"github.com/databricks/cli/bundle/deploy"
"github.com/databricks/cli/libs/diag"
"github.com/databricks/cli/libs/log"
)
type tfState struct {
Serial int64 `json:"serial"`
Lineage string `json:"lineage"`
}
type statePull struct {
filerFactory deploy.FilerFactory
}
func (l *statePull) Name() string {
return "terraform:state-pull"
}
func (l *statePull) remoteState(ctx context.Context, b *bundle.Bundle) (*tfState, []byte, error) {
f, err := l.filerFactory(b)
if err != nil {
return nil, nil, err
}
r, err := f.Read(ctx, TerraformStateFileName)
if err != nil {
return nil, nil, err
}
defer r.Close()
content, err := io.ReadAll(r)
if err != nil {
return nil, nil, err
}
state := &tfState{}
err = json.Unmarshal(content, state)
if err != nil {
return nil, nil, err
}
return state, content, nil
}
func (l *statePull) localState(ctx context.Context, b *bundle.Bundle) (*tfState, error) {
dir, err := Dir(ctx, b)
if err != nil {
return nil, err
}
content, err := os.ReadFile(filepath.Join(dir, TerraformStateFileName))
if err != nil {
return nil, err
}
state := &tfState{}
err = json.Unmarshal(content, state)
if err != nil {
return nil, err
}
return state, nil
}
func (l *statePull) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagnostics {
dir, err := Dir(ctx, b)
if err != nil {
return diag.FromErr(err)
}
localStatePath := filepath.Join(dir, TerraformStateFileName)
// Case: Remote state file does not exist. In this case we fallback to using the
// local Terraform state. This allows users to change the "root_path" their bundle is
// configured with.
remoteState, remoteContent, err := l.remoteState(ctx, b)
if errors.Is(err, fs.ErrNotExist) {
log.Infof(ctx, "Remote state file does not exist. Using local Terraform state.")
return nil
}
if err != nil {
return diag.Errorf("failed to read remote state file: %v", err)
}
// Expected invariant: remote state file should have a lineage UUID. Error
// if that's not the case.
if remoteState.Lineage == "" {
return diag.Errorf("remote state file does not have a lineage")
}
// Case: Local state file does not exist. In this case we should rely on the remote state file.
localState, err := l.localState(ctx, b)
if errors.Is(err, fs.ErrNotExist) {
log.Infof(ctx, "Local state file does not exist. Using remote Terraform state.")
err := os.WriteFile(localStatePath, remoteContent, 0600)
return diag.FromErr(err)
}
if err != nil {
return diag.Errorf("failed to read local state file: %v", err)
}
// If the lineage does not match, the Terraform state files do not correspond to the same deployment.
if localState.Lineage != remoteState.Lineage {
log.Infof(ctx, "Remote and local state lineages do not match. Using remote Terraform state. Invalidating local Terraform state.")
err := os.WriteFile(localStatePath, remoteContent, 0600)
return diag.FromErr(err)
}
// If the remote state is newer than the local state, we should use the remote state.
if remoteState.Serial > localState.Serial {
log.Infof(ctx, "Remote state is newer than local state. Using remote Terraform state.")
err := os.WriteFile(localStatePath, remoteContent, 0600)
return diag.FromErr(err)
}
// default: local state is newer or equal to remote state in terms of serial sequence.
// It is also of the same lineage. Keep using the local state.
return nil
}
func StatePull() bundle.Mutator {
return &statePull{deploy.StateFiler}
}