Gofer!

Gofer is a set of wrappers around the Net::SSH suite of tools to enable consistent access to remote systems.

Gofer has been written to support the needs of system automation scripts. As such, gofer will:

automatically raise an error if a command returns a non-zero exit status
print and capture STDOUT and STDERR automatically
allow you to access captured STDOUT and STDERR individually or as a combined string
override the above: return non-zero exit status instead of raising an error, suppress output
persist the SSH connection so that multiple commands don't incur connection penalties

Examples

Instantiation

h = Gofer::Host.new('my.host.com', 'ubuntu', :keys => ['key.pem'])

Run a command

h.run "sudo stop mysqld"

Copy some files

h.upload 'file', 'remote_file'
h.download 'remote_dir', 'dir'

Interact with the filesystem

if h.exist?('remote_directory')
  h.run "rm -rf 'remote_directory'"
end

h.write("a string buffer", 'a_remote_file')
puts h.read('a_remote_file')
puts h.ls('a_remote_dir').join(", ")

Respond to command errors

h.run "false" # this will raise an error
response = h.run "false", :capture_exit_status => true # this won't ...
puts response.exit_status # and will make the exit status available

Capture output

response = h.run "echo hello; echo goodbye 1>&2\n"
puts response         # will print "hello\n"
puts response.stdout  # will also print "hello\n"
puts response.stderr  # will print "goodbye\n"
puts response.output  # will print "hello\ngoodbye\n"

Suppress output

h.run "echo noisy", :quiet => true               # don't print stdout
h.run "echo noisier 1>&2", :quiet_stderr => true # don't print stderr
h.quiet = true                                   # never print stdout

Run multiple commands

response = h.run_multiple(['echo hello', 'echo goodbye'], :quiet => true)
puts response.stdout # will print "hello\ngoodbye\n"

Run the same commands on multiple hosts

cluster = Gopher::Cluster.new
cluster << Gofer::Host.new('my.host.com', 'ubuntu', :keys => ['key.pem'])
cluster << Gofer::Host.new('other.host.com', 'ubuntu', :keys => ['key.pem'])

cluster.run do |c|
    c.run("hostname") # This will run on both hosts at once
end

cluster.run(:max_concurrency => 1) do |c|
    c.run("sudo /etc/init.d/apache2 restart") # This will run on one machine at a time
end

Planned Features

# constant connection (no reconnect for each action)
Gofer::Host.new(...).open do |h|
  h.run( ... )
end

# overriding defaults
h.set :quiet => true
h.set :capture_exit_status => false

# Local system usage, too:
Gofer::Localhost.new.run "hostname" # > my.macbook.com

Testing

Ensure that your user can ssh as itself to localhost using the key in ~/.ssh/id_rsa.
Run rspec spec or bundle install && rake spec

TODO

ls, exists?, directory? should use sftp if available rather than shell commands
wrap STDOUT with host prefix for easy identification of system output
Deal with timeouts/disconnects on persistent connections
CHANGELOG.md
Release 1.0 & use Semver

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.