Aprilsh: remote shell support intermittent or mobile network. Inspired by mosh and zutty. aprilsh is a remote shell based on UDP, authenticate user via openssh.
Installation
Requirement
- open-ssh is a must requirement, sshd is required to perform user authentication.
- ncurses and terminfo is a must requirement.
- systmd is required by redhat linux family (fedora, centos, redhat).
- openrc is required by alpine linux.
- utmps is required by alpine linux.
- logrotate is a optional requirement by alpine.
- locale support is a build requirement.
If you prefer to build aprilsh manually, please refer to this document
Alpine linux
Before start apshd, you need to make sure you can ssh login to the target server, please refer to [this doc](doc/ssh-openrc.md) to setup a ssh enabled docker container. Refer to [build doc](doc/build.md) to know how to build apk packages and private repositories. ```sh # add testing repositories echo "https://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories # update repositories metadata apk update # install client and server apk add aprilsh ``` Now you can ssh login to the server, it's time to start apshd server and login with apsh. ```sh # start apshd server rc-service apshd start # apsh login with port mapping apsh -m 100 eric@localhost:8022 # apsh login without port mapping apsh eric@localhost ``` After apsh login, you connection to the remote server is provided by aprilsh.Fedora, CentOS, Redhat linux
Before start apshd, you need to make sure you can ssh login to the target server, please refer to [this doc](doc/ssh-systemd.md) to setup a ssh enabled docker container. Note: This is a private yum/dnf repositories, it only provides `x86_64` packages. Refer to [rpms doc](https://codeberg.org/ericwq/rpms#build-rpm-packages) to understand how to build rpm packages and dnf repositories. ```sh # import public key to rpm DB rpm --import https://ericwq.codeberg.page/RPM-GPG-KEY-wangqi # add new repo to dnf repository dnf config-manager --add-repo https://ericwq.codeberg.page/aprilsh.repo # install client and server dnf install -y aprilsh ``` Now you can ssh login to the server, it's time to start apshd service and login with apsh. ```sh sudo systemctl start apshd.service # start apshd service sudo journalctl -f -u apshd.service # keep reading the latest apshd.service log apsh -m 100 packager@localhost:8022 # apsh login to server apsh packager@localhost # apsh login without port mapping ``` After apsh login, you connection to the remote server is provided by aprilsh.MacOS
Run the following command to install aprilsh client for macOS. ```sh brew tap ericwq/utils # add tap to homebrew brew install aprilsh # only install aprilsh client ``` After apsh login, you connection to the remote server is provided by aprilsh. Refer to [homebrew doc](https://github.com/ericwq/homebrew-utils) to know how to create homebrew package and tap.Validate installation
by default apshd listen on udp localhost:8100. ```txt openrc-nvide:~# netstat -lup Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name udp 0 0 localhost:8100 0.0.0.0:* 45561/apshd openrc-nvide:~# ``` now login to the system with apsh (aprilsh client), note the `motd`(welcome message) depends on your linux system. ```txt qiwang@Qi15Pro client % apsh ide@localhost openrc-nvide:0.10.2 Lua, C/C++ and Golang Integrated Development Environment. Powered by neovim, luals, gopls and clangd. ide@openrc-nvide:~ $ ``` if you login on two terminals, on the server, there will be two server processes serve the clients. the following shows `apshd` serve two clients. one is`:8101`, the other is ':8102' ```txt openrc:~# netstat -lp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN 225/sshd [listener] tcp 0 0 :::ssh :::* LISTEN 225/sshd [listener] udp 0 0 localhost:8100 0.0.0.0:* 45561/apshd udp 0 0 :::8101 :::* 45647/apshd udp 0 0 :::8102 :::* 45612/apshd Active UNIX domain sockets (only servers) Proto RefCnt Flags Type State I-Node PID/Program name Path unix 2 [ ACC ] STREAM LISTENING 872486 159/s6-ipcserverd /run/utmps/.btmpd-socket unix 2 [ ACC ] STREAM LISTENING 869747 253/s6-ipcserverd /run/utmps/.utmpd-socket unix 2 [ ACC ] STREAM LISTENING 866239 281/s6-ipcserverd /run/utmps/.wtmpd-socket openrc-nvide:~# ```Motivation
openSSH is excellent. While mosh provides better keystroke prediction/latency and is capable of handle WiFi/cellular mobile network roaming. But mosh project is not active anymore and no release sine 2017. Such a good project like mosh should keeps developing.
After read through mosh source code, I decide to rewrite it with golang. Go is my first choice because the C++ syntax is too complex. Go also has excellent support for UTF-8 and multithreaded programming. The last reason: go compiler is faster than c++ compiler.
There are several rules for this project:
- Keep base design of
mosh:SSP, UDP, keystroke prediction. - Use 3rd party library as less as possible to keep it clean.
There are also some goals for this project:
- Full UTF-8 support, including emoji and flag support.
- Support terminal 24bit color.
- Upgrade to proto3
- Use terminfo database for better compatibility.
- Prove golang is a good choice for terminal developing.
The project name Aprilsh is derived from April+sh. This project started in shanghai April 2022, and it's a remote shell. Use the above command to add musl locales support and utmps support for alpine. Note alpine only support UTF-8 charmap.
Improvement
- prediction engine evaluate based on both user input response and server side timeout
- prediction engine support chinese character
- support XTGETTCAP, SGR 1006, synchronized output, OSC 8, CSI u
- support htop arrow key (mosh has a bug)
- support large volumes of output generated from terminal application (mosh has a bug)
- plan to support terminal query across multi-terminal emulator
Architecture
- The green part is provided by the system/terminal emulator. Such as alacritty or kitty.
- The cyan part is provided by
Aprilsh. - The yellow part is our target terminal application. In the above diagram it's
neovim. - Actually the yellow part can be any terminal based application: emcas, neovim, htop, etc.
- The rest part is provided by the system.
Set GOFLAGS="-tags=utmps" APRILSH_APSHD_PATH=~/.local/bin/apshd before nvim.
Changelog
Ready for early access. Check here for history detail.