README
¶
Wish
Make SSH apps, just like that! 💫
SSH is an excellent platform for building remotely accessible applications. It offers:
- secure communication without the hassle of HTTPS certificates
- user identification with SSH keys
- access from any terminal
Powerful protocols like Git work over SSH and you can even render TUIs directly over an SSH connection.
Wish is an SSH server with sensible defaults and a collection of middlewares that makes building SSH apps really easy. Wish is built on gliderlabs/ssh and should be easy to integrate into any existing projects.
What are SSH Apps?
Usually, when we think about SSH, we think about remote shell access into servers,
most commonly through openssh-server.
That's a perfectly valid (and probably the most common) use of SSH, but it can do so much more than that. Just like HTTP, SMTP, FTP and others, SSH is a protocol! It is a cryptographic network protocol for operating network services securely over an unsecured network. ^1
That means, among other things, that we can write custom SSH servers without touching openssh-server,
so we can securely do more things than just providing a shell.
Wish is a library that helps writing these kind of apps using Go.
Middleware
Wish middlewares are analogous to those in several HTTP frameworks. They are essentially SSH handlers that you can use to do specific tasks, and then call the next middleware.
Notice that middlewares are composed from first to last, which means the last one is executed first.
Bubble Tea
The bubbletea middleware makes it easy to serve any
Bubble Tea application over SSH. Each SSH session will get their own
tea.Program with the SSH pty input and output connected. Client window
dimension and resize messages are also natively handled by the tea.Program.
You can see a demo of the Wish middleware in action at: ssh git.charm.sh
Git
The git middleware adds git server functionality to any ssh server.
It supports repo creation on initial push and custom public key based auth.
This middleware requires that git is installed on the server.
Logging
The logging middleware provides basic connection logging. Connects
are logged with the remote address, invoked command, TERM setting, window
dimensions and if the auth was public key based. Disconnect will log the remote
address and connection duration.
Access Control
Not all applications will support general SSH connections. To restrict access
to supported methods, you can use the activeterm middleware to
only allow connections with active terminals connected and the
accesscontrol middleware that lets you specify allowed
commands.
Default Server
Wish includes the ability to easily create an always authenticating default SSH server with automatic server key generation.
Examples
There are examples for a standalone Bubble Tea application and Git server in the examples folder.
Apps Built With Wish
Pro tip
When building various Wish applications locally you can add the following to
your ~/.ssh/config to avoid having to clear out localhost entries in your
~/.ssh/known_hosts file:
Host localhost
UserKnownHostsFile /dev/null
How it works?
Wish uses gliderlabs/ssh to implement its SSH server, and OpenSSH is never used nor needed — you can even uninstall it if you want to.
Incidentally, there's no risk of accidentally sharing a shell because there's no default behavior that does that on Wish.
Running with SystemD
If you want to run a Wish app with systemd, you can create an unit like so:
/etc/systemd/system/myapp.service:
[Unit]
Description=My App
After=network.target
[Service]
Type=simple
User=myapp
Group=myapp
WorkingDirectory=/home/myapp/
ExecStart=/usr/bin/myapp
Restart=on-failure
[Install]
WantedBy=multi-user.target
You can tune the values below, and once you're happy with them, you can run:
# need to run this every time you change the unit file
sudo systemctl daemon-reload
# start/restart/stop/etc:
sudo systemctl start myapp
If you use a new user for each app (which is good), you'll need to create them first:
useradd --system --user-group --create-home myapp
That should do it.
Feedback
We’d love to hear your thoughts on this project. Feel free to drop us a note!
License
Part of Charm.
Charm热爱开源 • Charm loves open source
Documentation
¶
Index ¶
- func Error(s ssh.Session, v ...interface{})
- func Errorf(s ssh.Session, f string, v ...interface{})
- func Errorln(s ssh.Session, v ...interface{})
- func Fatal(s ssh.Session, v ...interface{})
- func Fatalf(s ssh.Session, f string, v ...interface{})
- func Fatalln(s ssh.Session, v ...interface{})
- func NewServer(ops ...ssh.Option) (*ssh.Server, error)
- func Print(s ssh.Session, v ...interface{})
- func Printf(s ssh.Session, f string, v ...interface{})
- func Println(s ssh.Session, v ...interface{})
- func WithAddress(addr string) ssh.Option
- func WithAuthorizedKeys(path string) ssh.Option
- func WithBanner(banner string) ssh.Option
- func WithBannerHandler(h ssh.BannerHandler) ssh.Option
- func WithHostKeyPEM(pem []byte) ssh.Option
- func WithHostKeyPath(path string) ssh.Option
- func WithIdleTimeout(d time.Duration) ssh.Option
- func WithKeyboardInteractiveAuth(h ssh.KeyboardInteractiveHandler) ssh.Option
- func WithMaxTimeout(d time.Duration) ssh.Option
- func WithMiddleware(mw ...Middleware) ssh.Option
- func WithPasswordAuth(p ssh.PasswordHandler) ssh.Option
- func WithPublicKeyAuth(h ssh.PublicKeyHandler) ssh.Option
- func WithSubsystem(key string, h ssh.SubsystemHandler) ssh.Option
- func WithTrustedUserCAKeys(path string) ssh.Option
- func WithVersion(version string) ssh.Option
- func WriteString(s ssh.Session, v string) (int, error)
- type Cmd
- type Middleware
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Error ¶
func Error(s ssh.Session, v ...interface{})
Error prints the given error the the session's STDERR.
func Errorf ¶
func Errorf(s ssh.Session, f string, v ...interface{})
Errorf formats according to the given format and prints to the session's STDERR.
func Errorln ¶
func Errorln(s ssh.Session, v ...interface{})
Errorf formats according to the default format and prints to the session's STDERR.
func Fatal ¶
func Fatal(s ssh.Session, v ...interface{})
Fatal prints to the given session's STDERR and exits 1.
func Fatalf ¶
func Fatalf(s ssh.Session, f string, v ...interface{})
Fatalf formats according to the given format, prints to the session's STDERR followed by an exit 1.
Notice that this might cause formatting issues if you don't add a \r\n in the end of your string.
func Fatalln ¶
func Fatalln(s ssh.Session, v ...interface{})
Fatalln formats according to the default format, prints to the session's STDERR, followed by a new line and an exit 1.
func NewServer ¶
func NewServer(ops ...ssh.Option) (*ssh.Server, error)
NewServer is returns a default SSH server with the provided Middleware. A new SSH key pair of type ed25519 will be created if one does not exist. By default this server will accept all incoming connections, password and public key.
func Print ¶
func Print(s ssh.Session, v ...interface{})
Print writes to the session's STDOUT followed.
func Printf ¶
func Printf(s ssh.Session, f string, v ...interface{})
Printf formats according to the given format and writes to the session's STDOUT.
func Println ¶
func Println(s ssh.Session, v ...interface{})
Println formats according to the default format and writes to the session's STDOUT.
func WithAddress ¶
func WithAddress(addr string) ssh.Option
WithAddress returns an ssh.Option that sets the address to listen on.
func WithAuthorizedKeys ¶
func WithAuthorizedKeys(path string) ssh.Option
WithAuthorizedKeys allows the use of an SSH authorized_keys file to allowlist users.
func WithBanner ¶
func WithBanner(banner string) ssh.Option
WithBanner return an ssh.Option that sets the server banner.
func WithBannerHandler ¶
func WithBannerHandler(h ssh.BannerHandler) ssh.Option
WithBannerHandler return an ssh.Option that sets the server banner handler, overriding WithBanner.
func WithHostKeyPEM ¶
func WithHostKeyPEM(pem []byte) ssh.Option
WithHostKeyPEM returns an ssh.Option that sets the host key from a PEM block.
func WithHostKeyPath ¶
func WithHostKeyPath(path string) ssh.Option
WithHostKeyFile returns an ssh.Option that sets the path to the private key.
func WithIdleTimeout ¶
WithIdleTimeout returns an ssh.Option that sets the connection's idle timeout.
func WithKeyboardInteractiveAuth ¶
func WithKeyboardInteractiveAuth(h ssh.KeyboardInteractiveHandler) ssh.Option
WithKeyboardInteractiveAuth returns an ssh.Option that sets the keyboard interactive auth handler.
func WithMaxTimeout ¶
WithMaxTimeout returns an ssh.Option that sets the connection's absolute timeout.
func WithMiddleware ¶
func WithMiddleware(mw ...Middleware) ssh.Option
WithMiddleware composes the provided Middleware and returns an ssh.Option. This is useful if you manually create an ssh.Server and want to set the Server.Handler.
Notice that middlewares are composed from first to last, which means the last one is executed first.
func WithPasswordAuth ¶
func WithPasswordAuth(p ssh.PasswordHandler) ssh.Option
WithPasswordAuth returns an ssh.Option that sets the password auth handler.
func WithPublicKeyAuth ¶
func WithPublicKeyAuth(h ssh.PublicKeyHandler) ssh.Option
WithPublicKeyAuth returns an ssh.Option that sets the public key auth handler.
func WithSubsystem ¶
func WithSubsystem(key string, h ssh.SubsystemHandler) ssh.Option
WithSubsystem returns an ssh.Option that sets the subsystem handler for a given protocol.
func WithTrustedUserCAKeys ¶
func WithTrustedUserCAKeys(path string) ssh.Option
WithTrustedUserCAKeys authorize certificates that are signed with the given Certificate Authority public key, and are valid. Analogous to the TrustedUserCAKeys OpenSSH option.
func WithVersion ¶
func WithVersion(version string) ssh.Option
WithVersion returns an ssh.Option that sets the server version.
func WriteString ¶
WriteString writes the given string to the session's STDOUT.
Types ¶
type Cmd ¶
type Cmd struct {
// contains filtered or unexported fields
}
Cmd wraps a *exec.Cmd and a ssh.Pty so a command can be properly run.
func Command ¶
Command sets stdin, stdout, and stderr to the current session's PTY.
If the current session does not have a PTY, it sets them to the session itself.
This will use the session's context as the context for exec.Command.
func CommandContext ¶
CommandContext is like Command but includes a context.
If the current session does not have a PTY, it sets them to the session itself.
type Middleware ¶
type Middleware func(next ssh.Handler) ssh.Handler
Middleware is a function that takes an ssh.Handler and returns an ssh.Handler. Implementations should call the provided handler argument.
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
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Package accesscontrol provides a middleware that allows you to restrict the commands the user can execute.
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Package accesscontrol provides a middleware that allows you to restrict the commands the user can execute. |
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Package activeterm provides a middleware to block inactive PTYs.
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Package activeterm provides a middleware to block inactive PTYs. |
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Package bubbletea provides middleware for serving bubbletea apps over SSH.
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Package bubbletea provides middleware for serving bubbletea apps over SSH. |
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Package ratelimiter provides basic rate limiting functionality as a with middleware.
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Package ratelimiter provides basic rate limiting functionality as a with middleware. |
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Package scp provides a SCP middleware for wish.
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Package scp provides a SCP middleware for wish. |
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Package testsession provides utilities to test SSH sessions.
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Package testsession provides utilities to test SSH sessions. |