builder.go

/*
Copyright 2019 The OpenEBS Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package premove

import (
	"fmt"
	"os/exec"
	"reflect"
	"runtime"
	"strings"

	"github.com/openebs/maya/pkg/zfs/cmd/v1alpha1/bin"
	"github.com/pkg/errors"
)

const (
	// Operation defines type of zfs operation
	Operation = "remove"
)

//PoolRemove defines structure for pool 'Remove' operation
type PoolRemove struct {
	//pool name
	Pool string

	//device list
	Device []string

	// command string
	Command string

	// checks is list of predicate function used for validating object
	checks []PredicateFunc

	// error
	err error
}

// NewPoolRemove returns new instance of object PoolRemove
func NewPoolRemove() *PoolRemove {
	return &PoolRemove{}
}

// WithCheck add given check to checks list
func (p *PoolRemove) WithCheck(check ...PredicateFunc) *PoolRemove {
	p.checks = append(p.checks, check...)
	return p
}

// WithPool method fills the Pool field of PoolRemove object.
func (p *PoolRemove) WithPool(Pool string) *PoolRemove {
	p.Pool = Pool
	return p
}

// WithDevice method fills the Device field of PoolRemove object.
func (p *PoolRemove) WithDevice(dev string) *PoolRemove {
	p.Device = append(p.Device, dev)
	return p
}

// WithCommand method fills the Command field of PoolRemove object.
func (p *PoolRemove) WithCommand(Command string) *PoolRemove {
	p.Command = Command
	return p
}

// Validate is to validate generated PoolRemove object by builder
func (p *PoolRemove) Validate() *PoolRemove {
	for _, check := range p.checks {
		if !check(p) {
			p.err = errors.Wrapf(p.err, "validation failed {%v}", runtime.FuncForPC(reflect.ValueOf(check).Pointer()).Name())
		}
	}
	return p
}

// Execute is to execute generated PoolRemove object
func (p *PoolRemove) Execute() ([]byte, error) {
	p, err := p.Build()
	if err != nil {
		return nil, err
	}
	// execute command here
	// #nosec
	return exec.Command(bin.BASH, "-c", p.Command).CombinedOutput()
}

// Build returns the PoolRemove object generated by builder
func (p *PoolRemove) Build() (*PoolRemove, error) {
	var c strings.Builder
	p = p.Validate()
	p.appendCommand(&c, bin.ZPOOL)
	p.appendCommand(&c, fmt.Sprintf(" %s ", Operation))

	p.appendCommand(&c, fmt.Sprintf(" %s ", p.Pool))

	if IsDeviceSet()(p) {
		for _, d := range p.Device {
			p.appendCommand(&c, fmt.Sprintf(" %s ", d))
		}
	}
	p.Command = c.String()
	return p, p.err
}

// appendCommand append string to given string builder
func (p *PoolRemove) appendCommand(c *strings.Builder, cmd string) {
	_, err := c.WriteString(cmd)
	if err != nil {
		p.err = errors.Wrapf(p.err, "Failed to append cmd{%s} : %s", cmd, err.Error())
	}
}