assh

 hosts :
  hosta :
    Hostname : 1.2.3.4

  hostb :
    Hostname : 5.6.7.8
    Gateways : hosta

  hostc :
    Hostname : 9.10.11.12
    Gateways : hostb

  hostd :
    Hostname : 13.14.15.16
    GatewayConnectTimeout : 2
    Gateways :
    - direct
    - hosta

 defaults :
  Hooks :
    OnConnect : exec echo '{{.Host}}' | jq .
# executes: `echo '{"HostName":"localhost","Port":"22","User":"moul","ControlPersist":"yes",...}' | jq .
# which results in printing a pretty JSON of the host
# {
#   "HostName": "localhost",
#   "Port": "22",
#   "User": "moul",
#   "ControlPersist": "yes",
#   ...
# } 

 defaults :
  Hooks :
    OnConnect : exec echo 'New SSH connection to {{.Host.Prototype}}.' | mail -s "SSH connection journal" m+ assh @42.am
# send an email with the connection prototype 

 defaults :
  Hooks :
    BeforeConfigWrite : exec cp {{.SSHConfigPath}} {{.SSHConfigPath}}.backup
# make a copy of ~/.ssh/config before being rewritten 

 defaults :
  Hooks :
    AfterConfigWrite : ' exec echo "# date: `date`" >> {{.SSHConfigPath}} '
# Append a comment with the compilation date to the generated ~/.ssh/config file 

 defaults :
  Hooks :
  AfterConfigWrite : ' exec cat /path/to/my/provider/generated/.ssh/config >> {{.SSHConfigPath}} '
# Append another .ssh/config file to the generated .ssh/config file

 defaults :
  Hooks :
    OnConnect :
    - exec sleep 60 &
# execute the `sleep 60` command in background (non-blocking)
# if you quit your ssh connection, the process will continue in background. 

 defaults :
  Hooks :
    OnConnect :
    - write New SSH connection to {{.Host.Prototype}}.
# writes: "New SSH connection to moul@127.0.0.1:22." on the terminal on connection 

 defaults :
  Hooks :
    OnDisconnect :
    - " write SSH connection to {{.Host.Name}} closed, {{ .Stats.WrittenBytes }} bytes written in {{ .Stats.ConnectionDuration }} ({{ .Stats.AverageSpeed }}) "
# writes: SSH connection to localhost closed, 40 bytes written. 

 defaults :
  Hooks :
    OnConnect : notify New SSH connection to {{.Host.Prototype}}. 

 defaults :
  Hooks :
    OnDisconnect :
    - " notify SSH connection to {{.Host.Name}} closed, {{ .Stats.WrittenBytes }} bytes written in {{ .Stats.ConnectionDuration }} ({{ .Stats.AverageSpeed }}) " 

 hosts :

  homer :
    # ssh homer ->  ssh 1.2.3.4 -p 2222 -u robert
    Hostname : 1.2.3.4
    User : robert
    Port : 2222

  bart :
    # ssh bart ->   ssh 5.6.7.8 -u bart           <- direct access
    #            or ssh 5.6.7.8/homer -u bart     <- using homer as a gateway
    Hostname : 5.6.7.8
    User : bart
    Gateways :
    - direct                   # tries a direct access first
    - homer                    # fallback on homer gateway

  maggie :
    # ssh maggie ->   ssh 5.6.7.8 -u maggie       <- direct access
    #              or ssh 5.6.7.8/homer -u maggie   <- using homer as a gateway
    User : maggie
    Inherits : bart             # inherits rules from "bart"

  bart-access :
    # ssh bart-access ->  ssh home.simpson.springfield.us -u bart
    Inherits :
    - bart-template
    - simpson-template

  lisa-access :
    # ssh lisa-access ->  ssh home.simpson.springfield.us -u lisa
    Inherits :
    - lisa-template
    - simpson-template

  marvin :
    # ssh marvin    -> ssh marvin    -p 23
    # ssh sad-robot -> ssh sad-robot -p 23
    # ssh bighead   -> ssh bighead   -p 23
    # aliases inherit everything from marvin, except hostname
    Port : 23
    Aliases :
    - sad-robot
    - bighead

  dolphin :
    # ssh dolphin   -> ssh dolphin -p 24
    # ssh ecco      -> ssh dolphin -p 24
    # same as above, but with fixed hostname
    Port : 24
    Hostname : dolphin
    Aliases : ecco
    RateLimit : 10M # 10Mbytes/second rate limiting

  schooltemplate :
    User : student
    IdentityFile : ~/.ssh/school-rsa
    ForwardX11 : yes

  schoolgw :
    # ssh school ->   ssh gw.school.com -l student -o ForwardX11=no -i ~/.ssh/school-rsa
    Hostname : gw.school.com
    ForwardX11 : no
    Inherits : schooltemplate

  " expanded-host[0-7]* " :
    # ssh somehost2042 ->       ssh somehost2042.some.zone
    Hostname : " %h.some.zone "

  vm-*.school.com :
    # ssh vm-42.school.com ->   ssh vm-42.school.com/gw.school.com -l student -o ForwardX11=yes -i ~/.ssh/school-rsa
    Gateways : schoolgw
    Inherits : schooltemplate
    # do not automatically create `ControlPath` -> may result in error
    ControlMasterMkdir : true

  " *.shortcut1 " :
    ResolveCommand : /bin/sh -c "echo %h | sed s/.shortcut1/.my-long-domain-name.com/"

  " *.shortcut2 " :
    ResolveCommand : /bin/sh -c "echo $(echo %h | sed s/.shortcut2//).my-other-long-domain-name.com"

  " *.scw " :
    # ssh toto.scw -> 1. dynamically resolves the IP address
    #                 2. ssh {resolved ip address} -u root -p 22 -o UserKnownHostsFile=null -o StrictHostKeyChecking=no
    # requires github.com/scaleway/scaleway-cli
    ResolveCommand : /bin/sh -c "scw inspect -f {{.PublicAddress.IP}} server:$(echo %h | sed s/.scw//)"
    User : root
    Port : 22
    UserKnownHostsFile : /dev/null
    StrictHostKeyChecking : no

  my-env-host :
    User : user-$USER
    Hostname : ${HOSTNAME}${HOSTNAME_SUFFIX}

templates :
  # Templates are similar to Hosts; you can inherit from them
  # but you cannot ssh to a template
  bart-template :
    User : bart
  lisa-template :
    User : lisa
  simpson-template :
    Host : home.simpson.springfield.us

defaults :
  # Defaults are applied to each hosts
  ControlMaster : auto
  ControlPath : ~/tmp/.ssh/cm/%h-%p-%r.sock
  ControlPersist : yes
  Port : 22
  User : bob
  Hooks :
    # Automatically backup ~/.ssh/config
    BeforeConfigWrite :
      - ' exec set -x; cp {{.SSHConfigPath}} {{.SSHConfigPath}}.bkp '

    AfterConfigWrite :
      # Concat another `ssh_config` file with the one just generated by ` assh `
      - ' exec cat ~/.ssh/my-heroku-generated-config >> {{.SSHConfigPath}} '

      # Alert me with a Desktop notification
      - notify "{{.SSHConfigPath}} has been rewritten"

    OnConnect :
      # Log internal information to a file
      - exec printf '{{.}}' | jq . >> ~/.ssh/last_connected_host.txt

      # Alert me with a Desktop notification
      - notify New SSH connection to {{.Host.Prototype}} at {{.Stats.ConnectedAt}}

      # Write the host prototype to the terminal stderr
      - write New SSH connection to {{.Host.Prototype}}

    OnDisconnect :
      # write on terminal and in a Desktop notification some statistics about the finished connection
      - " write  SSH connection to {{.Host.HostName}} closed, {{.Stats.WrittenBytes }} bytes written in {{.Stats.ConnectionDuration}} ({{.Stats.AverageSpeed}}bps) "
      - " notify SSH connection to {{.Host.HostName}} closed, {{.Stats.WrittenBytes }} bytes written in {{.Stats.ConnectionDuration}} ({{.Stats.AverageSpeed}}bps) "

includes :
- ~/.ssh/ assh .d/*.yml
- /etc/ assh .yml
- $ENV_VAR/blah-blah-*/*.yml

assh BinaryPath : ~/bin/ assh  # optionally set the path of assh