ohgossh

SSH alternative command line client written in Go

Why use ohgossh?

While configuring my ssh_config for the Nth time, I just figured "Why not make an alternative client, which will allow Regexp patterns for matching hostnames, and using a template for rendering hostname and other options to use!?"

So I did. I made this project in Go. Using the golang.org/x/crypto library, which provides most of what is needed for actually connecting to an SSH server, and golang.org/x/term for some terminal stuff.

What is implemented?

• Simple ssh command line interface
• Regexp pattern matching of hosts
• Go template rendering of hostname and options
• Piping the ssh connection to terminal, and making it actually usable
• GSSAPI authentication
• HTTP proxying of ssh connection

Config format

ohgossh uses the yaml format for the config file. The yaml config allows users to add their own PERL compatible regexp patterns and using Go templates for rendering hostnames and options.

There is a json-schema, for the config file, available here: schema/config.schema.json

Here is an example config from config/examples/regexp.yml:

---

defaults:
  user: "{{ default .User .ShellUser }}"
  timeout: "10s"
  identityFile: "~/.ssh/id_rsa{{if ne .User .ShellUser}}.{{.User}}{{end}}"
  preferredAuthentications:
    - gssapi-with-mic
    - publickey
    - password

hosts:
  - pattern: "jump-(uk|us)\\.(dev|stage)"
    replace: "jumphost-0{{if eq c1 `uk`}}{{ randomChoice 1 2 }}{{else}}{{ randomChoice 3 4 }}{{end}}.{{ c2 }}.example.domain"
    user: admin

  - pattern: "jump-(uk|us)\\.prod"
    replace: "jumpprod-{{if eq c1 `uk`}}{{ randomChoice 1 2 }}{{else}}{{ randomChoice 3 4 }}{{end}}.example.domain"
    user: "prod-admin"
    gssApi:
      enabled: true
      delegateCredentials: true

  - pattern: "k8s-((master|worker)[0-9]*)-(uk|us)\\.(dev|stage|prod)"
    replace: "{{ c1 }}-{{ c2 }}-{{ c4 }}.{{ c5 }}"
    user: "core"
    identityFile: "~/.ssh/id_rsa.ansible"

  - pattern: "((?!jump).*?-(uk|us))\\.(dev|stage|prod)"
    replace: "{{ c1 }}"
    jumpHost: "jump-{{ c2 }}.{{ c3 }}"

  - name: "github.com"
    aliases:
      - github
    httpProxy:
      host: proxy.localhost
      port: 8080