hoster

README

Hoster is a cross-platform operating system host file management library written in Go.

Features | Installation | Usage | CLI

Features

• Cross platform: support Linux / Windows / macOS(darwin)
• Lookup by address(IPv4, IPv6 etc.) and host(domains).
• Host file backup and duplication.
• CLI cmd/hoster for manipulating host file in terminal.

Installation

Requirements:

• Golang version v1.13.0 (minimum)

Installation:

go get -u -v github.com/monitor1379/hoster

Usage

Create

Create a *HostManager and print the content of host file:

package main


import (
	"fmt"
	"time"

	"github.com/monitor1379/hoster"
)

func main() {
	// create a *HostManager
	hm, err := hoster.Default()
	if err != nil {
		panic(err)
	}

	// print:
	// "/etc/hosts" in non-Windows OS
	// or
	// "C:\Windows\System32\drivers\etc\hosts" in Windows
	fmt.Println(hm.HostFilePath())

	// print your host file content
	fmt.Println(hm.String())
}

Lookup

Assuming your host file content is:

127.0.0.1 localhost

192.168.10.10 hoster-1.k8s.svc.cluster.local  hoster-2.k8s.svc.cluster.local    # my kubernetes services
192.168.10.11 other-app.example.com


# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback

Lookup by address(ip) or host(domain):

package main

import (
	"fmt"

	"github.com/monitor1379/hoster"
)

func main() {
	hm, err := hoster.New("./hosts.txt")
	if err != nil {
		panic(err)
	}

	mapping, ok := hm.LookupByAddress("192.168.10.10")
	fmt.Println(ok)              // true
	fmt.Println(mapping.Address) // 192.168.10.10
	fmt.Println(mapping.Hosts)   // []string{"hoster-1.k8s.svc.cluster.local", "hoster-2.k8s.svc.cluster.local"}
	fmt.Println(mapping.Comment) // # my kubernetes services

	mapping, ok = hm.LookupByHost("hoster-2.k8s.svc.cluster.local")
	fmt.Println(ok)              // true
	fmt.Println(mapping.Address) // 192.168.10.10
	fmt.Println(mapping.Hosts)   // []string{"hoster-1.k8s.svc.cluster.local", "hoster-2.k8s.svc.cluster.local"}
	fmt.Println(mapping.Comment) // # my kubernetes services
}

Set and Delete

package main

import (
	"fmt"

	"github.com/monitor1379/hoster"
)

func main() {
	// hm is managing "./hosts.txt"
	hm, err := hoster.New("./hosts.txt")
	if err != nil {
		panic(err)
	}

	fmt.Println(hm.String())
	// print:
	// 127.0.0.1       localhost
	//
	// 192.168.10.10   hoster-1.k8s.svc.cluster.local  hoster-2.k8s.svc.cluster.local  # my kubernetes services
	// 192.168.10.11   other-app.example.com
	//
	// # The following lines are desirable for IPv6 capable hosts
	// ::1     ip6-localhost   ip6-loopback

	// hm2 is managing "./hosts2.txt" which content is copied from "./hosts.txt"
	hm2, err := hm.Duplicate("./host2.txt")
	if err != nil {
		panic(err)
	}

	err = hm2.Set("hoster-2.k8s.svc.cluster.local", "192.168.10.12", "# added by monitor1379")
	if err != nil {
		panic(err)
	}
	fmt.Println(hm2.String())
	// print:
	// 127.0.0.1       localhost
	//
	// 192.168.10.10   hoster-1.k8s.svc.cluster.local  # my kubernetes services
	// 192.168.10.11   other-app.example.com
	//
	// # The following lines are desirable for IPv6 capable hosts
	// ::1     ip6-localhost   ip6-loopback
	// 192.168.10.12   hoster-2.k8s.svc.cluster.local  # added by monitor1379

	err = hm2.DeleteHost("hoster-2.k8s.svc.cluster.local")
	if err != nil {
		panic(err)
	}
	fmt.Println(hm2.String())
	// print:
	// 127.0.0.1       localhost
	//
	// 192.168.10.10   hoster-1.k8s.svc.cluster.local  # my kubernetes services
	// 192.168.10.11   other-app.example.com
	//
	// # The following lines are desirable for IPv6 capable hosts
	// ::1     ip6-localhost   ip6-loopback

}

Backup

backup host file to a new path:

package main

import (
	"github.com/monitor1379/hoster"
)

func main() {
	hm, err := hoster.New("./hosts.txt")
	if err != nil {
		panic(err)
	}

	// note that after backup, hm is still managing "./hosts.txt"
	err = hm.Backup("./hosts-backup.txt")
	if err != nil {
		panic(err)
	}
}

CLI

cmd/hoster is a command-line program for manipulating host file in terminal.

common methods:

• hoster version
• hoster list [--file <host-file-path>]
• hoster lookup [--file <host-file-path>] [--address <address>] [--host <host>]
• hoster set [--file <host-file-path>] [--address <address>] [--host <host>] [--comment <comment>

> hoster

Hoster is a cross-platform operating system host file management library written in Go.

Usage:
  hoster [command]

Available Commands:
  help        Help about any command
  list        List address-host mappings
  lookup      lookup by address or host
  set         Add a address-host mapping
  version     Print the version of hoster

Flags:
  -f, --file string   specify a host file path (default "/etc/hosts")
  -h, --help          help for hoster

Use "hoster [command] --help" for more information about a command.

List command:

> hoster list

+-----------+-----------------+
|  ADDRESS  |      HOST       |
+-----------+-----------------+
| 127.0.0.1 | localhost       |
| 127.0.1.1 | red-coast-base  |
| ::1       | ip6-localhost   |
| ::1       | ip6-loopback    |
| fe00::0   | ip6-localnet    |
| ff00::0   | ip6-mcastprefix |
| ff02::1   | ip6-allnodes    |
| ff02::2   | ip6-allrouters  |
+-----------+-----------------+

Documentation

Index

• func Flush(hostFilePath string, mappings []*Mapping) error
• func GetSysHostFilePath() (string, error)
• type HostManager
  • func Default() (*HostManager, error)
  • func New(hostFilePath string) (*HostManager, error)
  • func (h *HostManager) Backup(backupHostFilePath string) error
  • func (h *HostManager) DeleteHost(host string) error
  • func (h *HostManager) Duplicate(newHostFilePath string) (*HostManager, error)
  • func (h *HostManager) HostFilePath() string
  • func (h *HostManager) LookupByAddress(address string) (*Mapping, bool)
  • func (h *HostManager) LookupByHost(host string) (*Mapping, bool)
  • func (h *HostManager) Mappings() []*Mapping
  • func (h *HostManager) Set(host, address, comment string) error
  • func (h *HostManager) String() string
• type Mapping
  • func Decode(line string) (*Mapping, error)
  • func Parse(data []byte) ([]*Mapping, error)
  • func ParseFile(hostFilePath string) ([]*Mapping, error)
  • func (m *Mapping) Decode(line string) error
  • func (m Mapping) Encode() string
  • func (m Mapping) IsEmptyLine() bool
  • func (m Mapping) IsOnlyComment() bool
  • func (m Mapping) String() string

Functions

func Flush

func Flush(hostFilePath string, mappings []*Mapping) error

func GetSysHostFilePath

func GetSysHostFilePath() (string, error)

Types

type HostManager

type HostManager struct {
	// contains filtered or unexported fields
}

func Default

func Default() (*HostManager, error)

Default returns a `*HostManager` with system host file path.

func New

func New(hostFilePath string) (*HostManager, error)

New returns a `*HostManager` with given host file path.

func (*HostManager) Backup

func (h *HostManager) Backup(backupHostFilePath string) error

func (*HostManager) DeleteHost

func (h *HostManager) DeleteHost(host string) error

func (*HostManager) Duplicate

func (h *HostManager) Duplicate(newHostFilePath string) (*HostManager, error)

func (*HostManager) HostFilePath

func (h *HostManager) HostFilePath() string

func (*HostManager) LookupByAddress

func (h *HostManager) LookupByAddress(address string) (*Mapping, bool)

func (*HostManager) LookupByHost

func (h *HostManager) LookupByHost(host string) (*Mapping, bool)

func (*HostManager) Mappings

func (h *HostManager) Mappings() []*Mapping

func (*HostManager) Set

func (h *HostManager) Set(host, address, comment string) error

Set set the ip of host as address, and flush to host file.

func (*HostManager) String

func (h *HostManager) String() string

type Mapping

type Mapping struct {
	Address string
	Hosts   []string
	Comment string
}

func Decode

func Decode(line string) (*Mapping, error)

func Parse

func Parse(data []byte) ([]*Mapping, error)

func ParseFile

func ParseFile(hostFilePath string) ([]*Mapping, error)

func (*Mapping) Decode

func (m *Mapping) Decode(line string) error

func (Mapping) Encode

func (m Mapping) Encode() string

func (Mapping) IsEmptyLine

func (m Mapping) IsEmptyLine() bool

func (Mapping) IsOnlyComment

func (m Mapping) IsOnlyComment() bool

func (Mapping) String

func (m Mapping) String() string