github.com/iaas-resource-provision/iaas-rpc@v1.0.7-0.20211021023331-ed21f798c408/internal/backend/local/backend_apply.go

package local

import (
	"context"
	"fmt"
	"log"

	"github.com/hashicorp/errwrap"
	"github.com/iaas-resource-provision/iaas-rpc/internal/backend"
	"github.com/iaas-resource-provision/iaas-rpc/internal/command/views"
	"github.com/iaas-resource-provision/iaas-rpc/internal/plans"
	"github.com/iaas-resource-provision/iaas-rpc/internal/states"
	"github.com/iaas-resource-provision/iaas-rpc/internal/states/statefile"
	"github.com/iaas-resource-provision/iaas-rpc/internal/states/statemgr"
	"github.com/iaas-resource-provision/iaas-rpc/internal/terraform"
	"github.com/iaas-resource-provision/iaas-rpc/internal/tfdiags"
)

func (b *Local) opApply(
	stopCtx context.Context,
	cancelCtx context.Context,
	op *backend.Operation,
	runningOp *backend.RunningOperation) {
	log.Printf("[INFO] backend/local: starting Apply operation")

	var diags tfdiags.Diagnostics

	// If we have a nil module at this point, then set it to an empty tree
	// to avoid any potential crashes.
	if op.PlanFile == nil && op.PlanMode != plans.DestroyMode && !op.HasConfig() {
		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"No configuration files",
			"Apply requires configuration to be present. Applying without a configuration "+
				"would mark everything for destruction, which is normally not what is desired. "+
				"If you would like to destroy everything, run 'iaas-rpc destroy' instead.",
		))
		op.ReportResult(runningOp, diags)
		return
	}

	stateHook := new(StateHook)
	op.Hooks = append(op.Hooks, stateHook)

	// Get our context
	tfCtx, _, opState, contextDiags := b.context(op)
	diags = diags.Append(contextDiags)
	if contextDiags.HasErrors() {
		op.ReportResult(runningOp, diags)
		return
	}
	// the state was locked during succesfull context creation; unlock the state
	// when the operation completes
	defer func() {
		diags := op.StateLocker.Unlock()
		if diags.HasErrors() {
			op.View.Diagnostics(diags)
			runningOp.Result = backend.OperationFailure
		}
	}()

	runningOp.State = tfCtx.State()

	// If we weren't given a plan, then we refresh/plan
	if op.PlanFile == nil {
		// Perform the plan
		log.Printf("[INFO] backend/local: apply calling Plan")
		plan, planDiags := tfCtx.Plan()
		diags = diags.Append(planDiags)
		if planDiags.HasErrors() {
			op.ReportResult(runningOp, diags)
			return
		}

		trivialPlan := !plan.CanApply()
		hasUI := op.UIOut != nil && op.UIIn != nil
		mustConfirm := hasUI && !op.AutoApprove && !trivialPlan
		op.View.Plan(plan, tfCtx.Schemas())

		if mustConfirm {
			var desc, query string
			switch op.PlanMode {
			case plans.DestroyMode:
				if op.Workspace != "default" {
					query = "Do you really want to destroy all resources in workspace \"" + op.Workspace + "\"?"
				} else {
					query = "Do you really want to destroy all resources?"
				}
				desc = "IaaS-RPC will destroy all your managed infrastructure, as shown above.\n" +
					"There is no undo. Only 'yes' will be accepted to confirm."
			case plans.RefreshOnlyMode:
				if op.Workspace != "default" {
					query = "Would you like to update the IaaS-RPC state for \"" + op.Workspace + "\" to reflect these detected changes?"
				} else {
					query = "Would you like to update the IaaS-RPC state to reflect these detected changes?"
				}
				desc = "IaaS-RPC will write these changes to the state without modifying any real infrastructure.\n" +
					"There is no undo. Only 'yes' will be accepted to confirm."
			default:
				if op.Workspace != "default" {
					query = "Do you want to perform these actions in workspace \"" + op.Workspace + "\"?"
				} else {
					query = "Do you want to perform these actions?"
				}
				desc = "IaaS-RPC will perform the actions described above.\n" +
					"Only 'yes' will be accepted to approve."
			}

			// We'll show any accumulated warnings before we display the prompt,
			// so the user can consider them when deciding how to answer.
			if len(diags) > 0 {
				op.View.Diagnostics(diags)
				diags = nil // reset so we won't show the same diagnostics again later
			}

			v, err := op.UIIn.Input(stopCtx, &terraform.InputOpts{
				Id:          "approve",
				Query:       "\n" + query,
				Description: desc,
			})
			if err != nil {
				diags = diags.Append(errwrap.Wrapf("Error asking for approval: {{err}}", err))
				op.ReportResult(runningOp, diags)
				return
			}
			if v != "yes" {
				op.View.Cancelled(op.PlanMode)
				runningOp.Result = backend.OperationFailure
				return
			}
		}
	} else {
		plan, err := op.PlanFile.ReadPlan()
		if err != nil {
			diags = diags.Append(tfdiags.Sourceless(
				tfdiags.Error,
				"Invalid plan file",
				fmt.Sprintf("Failed to read plan from plan file: %s.", err),
			))
			op.ReportResult(runningOp, diags)
			return
		}
		for _, change := range plan.Changes.Resources {
			if change.Action != plans.NoOp {
				op.View.PlannedChange(change)
			}
		}
	}

	// Set up our hook for continuous state updates
	stateHook.StateMgr = opState

	// Start the apply in a goroutine so that we can be interrupted.
	var applyState *states.State
	var applyDiags tfdiags.Diagnostics
	doneCh := make(chan struct{})
	go func() {
		defer close(doneCh)
		log.Printf("[INFO] backend/local: apply calling Apply")
		_, applyDiags = tfCtx.Apply()
		// we always want the state, even if apply failed
		applyState = tfCtx.State()
	}()

	if b.opWait(doneCh, stopCtx, cancelCtx, tfCtx, opState, op.View) {
		return
	}
	diags = diags.Append(applyDiags)

	// Store the final state
	runningOp.State = applyState
	err := statemgr.WriteAndPersist(opState, applyState)
	if err != nil {
		// Export the state file from the state manager and assign the new
		// state. This is needed to preserve the existing serial and lineage.
		stateFile := statemgr.Export(opState)
		if stateFile == nil {
			stateFile = &statefile.File{}
		}
		stateFile.State = applyState

		diags = diags.Append(b.backupStateForError(stateFile, err, op.View))
		op.ReportResult(runningOp, diags)
		return
	}

	if applyDiags.HasErrors() {
		op.ReportResult(runningOp, diags)
		return
	}

	// If we've accumulated any warnings along the way then we'll show them
	// here just before we show the summary and next steps. If we encountered
	// errors then we would've returned early at some other point above.
	op.View.Diagnostics(diags)
}

// backupStateForError is called in a scenario where we're unable to persist the
// state for some reason, and will attempt to save a backup copy of the state
// to local disk to help the user recover. This is a "last ditch effort" sort
// of thing, so we really don't want to end up in this codepath; we should do
// everything we possibly can to get the state saved _somewhere_.
func (b *Local) backupStateForError(stateFile *statefile.File, err error, view views.Operation) tfdiags.Diagnostics {
	var diags tfdiags.Diagnostics

	diags = diags.Append(tfdiags.Sourceless(
		tfdiags.Error,
		"Failed to save state",
		fmt.Sprintf("Error saving state: %s", err),
	))

	local := statemgr.NewFilesystem("errored.tfstate")
	writeErr := local.WriteStateForMigration(stateFile, true)
	if writeErr != nil {
		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"Failed to create local state file",
			fmt.Sprintf("Error creating local state file for recovery: %s", writeErr),
		))

		// To avoid leaving the user with no state at all, our last resort
		// is to print the JSON state out onto the terminal. This is an awful
		// UX, so we should definitely avoid doing this if at all possible,
		// but at least the user has _some_ path to recover if we end up
		// here for some reason.
		if dumpErr := view.EmergencyDumpState(stateFile); dumpErr != nil {
			diags = diags.Append(tfdiags.Sourceless(
				tfdiags.Error,
				"Failed to serialize state",
				fmt.Sprintf(stateWriteFatalErrorFmt, dumpErr),
			))
		}

		diags = diags.Append(tfdiags.Sourceless(
			tfdiags.Error,
			"Failed to persist state to backend",
			stateWriteConsoleFallbackError,
		))
		return diags
	}

	diags = diags.Append(tfdiags.Sourceless(
		tfdiags.Error,
		"Failed to persist state to backend",
		stateWriteBackedUpError,
	))

	return diags
}

const stateWriteBackedUpError = `The error shown above has prevented IaaS-RPC from writing the updated state to the configured backend. To allow for recovery, the state has been written to the file "errored.tfstate" in the current working directory.

Running "iaas-rpc apply" again at this point will create a forked state, making it harder to recover.

To retry writing this state, use the following command:
    iaas-rpc state push errored.tfstate
`

const stateWriteConsoleFallbackError = `The errors shown above prevented IaaS-RPC from writing the updated state to
the configured backend and from creating a local backup file. As a fallback,
the raw state data is printed above as a JSON object.

To retry writing this state, copy the state data (from the first { to the last } inclusive) and save it into a local file called errored.tfstate, then run the following command:
    iaas-rpc state push errored.tfstate
`

const stateWriteFatalErrorFmt = `Failed to save state after apply.

Error serializing state: %s

A catastrophic error has prevented IaaS-RPC from persisting the state file or creating a backup. Unfortunately this means that the record of any resources created during this apply has been lost, and such resources may exist outside of IaaS-RPC's management.

For resources that support import, it is possible to recover by manually importing each resource using its id from the target system.

This is a serious bug in IaaS-RPC and should be reported.
`