tasks/common/persistence/faultinjection/fault.go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package faultinjection

import (
	"context"
	"fmt"

	enumspb "go.temporal.io/api/enums/v1"
	"go.temporal.io/api/serviceerror"
	"go.temporal.io/server/common/persistence"
)

type (
	fault struct {
		err error
		// execOp indicates whether the operation should be executed before returning the error.
		execOp bool
		// How often this fault should be injected. 0.0 means never, 1.0 means always.
		rate float64
	}
)

func newFaultFromError(err error, rate float64) fault {
	return fault{
		err:  err,
		rate: rate,
	}
}

// newFault returns an error based on the provided name. If the name is not recognized, then this method will
// panic.
func newFault(errName string, errRate float64, methodName string) fault {
	header := fmt.Sprintf("fault injection error at %s with %.2f rate", methodName, errRate)
	switch errName {
	case "ShardOwnershipLost":
		return newFaultFromError(&persistence.ShardOwnershipLostError{Msg: fmt.Sprintf("%s: persistence.ShardOwnershipLostError", header)}, errRate)
	case "DeadlineExceeded":
		// Real persistence store never returns context.DeadlineExceeded error. It returns persistence.TimeoutError instead.
		// Therefor "DeadlineExceeded" shouldn't be used with fault injection. Use "Timeout" instead.
		return newFaultFromError(fmt.Errorf("%s: %w", header, context.DeadlineExceeded), errRate)
	case "Timeout":
		return newFaultFromError(&persistence.TimeoutError{Msg: fmt.Sprintf("%s: persistence.TimeoutError", header)}, errRate)
	case "ExecuteAndTimeout":
		// Special error which emulates case, when caller got a Timeout error,
		// but operation actually reached persistence and was executed successfully.
		f := newFaultFromError(&persistence.TimeoutError{Msg: fmt.Sprintf("%s: persistence.TimeoutError", header)}, errRate)
		f.execOp = true
		return f
	case "ResourceExhausted":
		return newFaultFromError(&serviceerror.ResourceExhausted{
			Cause:   enumspb.RESOURCE_EXHAUSTED_CAUSE_SYSTEM_OVERLOADED,
			Scope:   enumspb.RESOURCE_EXHAUSTED_SCOPE_SYSTEM,
			Message: fmt.Sprintf("%s: serviceerror.ResourceExhausted", header),
		}, errRate)
	case "Unavailable":
		return newFaultFromError(serviceerror.NewUnavailable(fmt.Sprintf("%s: serviceerror.Unavailable", header)), errRate)
	default:
		panic(fmt.Sprintf("unsupported error type: %v", errName))
	}
}

func (f *fault) inject(op func() error) error {
	if f == nil {
		return op()
	}
	if f.execOp {
		err := op()
		if err != nil {
			return err
		}
	}
	return f.err
}