Command
Kanrisuru::Command class encapsulates the process of creating commands to run on a remote server. This class also handles the raw stdout and stderror responses sent from the server, as well as the exit status.
Public Class Methods
new
Instantiating a new instance of Kanrisuru::Command should start with the base command name:
command = Kanrisuru::Command.new("uptime")
Public Instance Methods
append_value
Appends a value to the raw command. Note: This will automatically add white space between the command and new field added.
Note: << and + are aliases to this method.
command = Kanrisuru::Command.new("hello")
command.raw_command
"hello"
command.append_value("world")
command.raw_command
"hello world"
command << "-w options"
command.raw_command
"hello world -w options"
command + "-n fields"
command.raw_command
"hello world -w options -n fields"
pipe
Adds a pipe character when adding an option to a command. Mostly syntax sugar for building commands with piped programs in linux.
Note: | is an alias to this method.
command = Kanrisuru::Command.new("ps aux")
command.pipe("grep root")
command.raw_command
"ps aux | grep root"
command | "sort"
command.raw_command
"ps aux | grep root | sort"
append_arg
Appends an argument to the command. This evaluates if the acutal argument is present or not to add to the command.
command = Kanrisuru::Command.new("groupadd rails")
command.append_arg("-g", nil)
command.raw_command
"groupadd rails"
command.append_arg("-g", 2000)
command.raw_command
"groupadd rails -g 2000"
append_flag
Appends a flag to the command. Evalutes boolean expression as second argument to append or not to the command.
command = Kanrisuru::Command.new("wget")
command.append_flag("--quiet", true)
command.raw_command
"wget --quiet"
append_valid_exit_code
Append a valid exit code to evaluate if the command was run successfully. Most commands use an exist code of 0, so this shouldn’t need to be called often. But there’s a few programs that use non-zero statuses that are considered succesful.
command = Kanrisuru::Command.new("zypper")
command.append_valid_exit_code(Kanrisuru::Core::Zypper::EXIT_INF_UPDATE_NEEDED)
command.handle_status(100)
command.success?
true
success?
Returns true if the valid_exit_codes include the the @exist_status.
command = Kanrisuru::Command.new('whoami')
command.handle_status(0)
command.success?
true
failure?
Returns true if the valid_exit_code does not include the @exit_status
command = Kanrisuru::Command.new('whoami')
command.handle_status(1)
command.failure?
true
to_a
Returns an array of strings split on \n characters.
command = Kanrisuru::Command.new('whoami')
command.handle_data("hello\n world")
command.to_a
[
"hello",
"world"
]
to_i
Attempts to cast result into an integer.
command = Kanrisuru::Command.new('whoami')
command.handle_data("124")
command.to_i
124
to_s
Casts entire return result as a single string, with splitting on the \n character.
command = Kanrisuru::Command.new('whoami')
command.handle_data("hello\n world")
command.to_s
"hello world"
to_json
Attempts to parse stringified version of result. Useful when a command has a JSON output mode.
command = Kanrisuru::Command.new('lsblk')
command.handle_data("{\n \"blockdevices\": [\n {\"name\":\"loop0\", \"fstype\":\"squashfs\", \"maj:min\":\"7:0\", \"mountpoint\":\"/snap/core18/2074\", \"size\":\"55.5M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop1\", \"fstype\":\"squashfs\", \"maj:min\":\"7:1\", \"mountpoint\":\"/snap/core18/2128\", \"size\":\"55.4M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop2\", \"fstype\":\"squashfs\", \"maj:min\":\"7:2\", \"mountpoint\":\"/snap/core20/1169\", \"size\":\"61.9M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop3\", \"fstype\":\"squashfs\", \"maj:min\":\"7:3\", \"mountpoint\":\"/snap/lxd/21029\", \"size\":\"70.3M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop4\", \"fstype\":\"squashfs\", \"maj:min\":\"7:4\", \"mountpoint\":\"/snap/core20/1081\", \"size\":\"61.8M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop6\", \"fstype\":\"squashfs\", \"maj:min\":\"7:6\", \"mountpoint\":\"/snap/snapd/13170\", \"size\":\"32.3M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop7\", \"fstype\":\"squashfs\", \"maj:min\":\"7:7\", \"mountpoint\":\"/snap/lxd/21545\", \"size\":\"67.3M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"loop8\", \"fstype\":\"squashfs\", \"maj:min\":\"7:8\", \"mountpoint\":\"/snap/snapd/13270\", \"size\":\"32.4M\", \"uuid\":null, \"ro\":true, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"loop\"},\n {\"name\":\"vda\", \"fstype\":null, \"maj:min\":\"252:0\", \"mountpoint\":null, \"size\":\"8G\", \"uuid\":null, \"ro\":false, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"disk\",\n \"children\": [\n {\"name\":\"vda1\", \"fstype\":\"ext4\", \"maj:min\":\"252:1\", \"mountpoint\":\"/\", \"size\":\"7.9G\", \"uuid\":\"b8976b0d-6f88-49b9-8e4a-787323d98d2c\", \"ro\":false, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"part\"},\n {\"name\":\"vda14\", \"fstype\":null, \"maj:min\":\"252:14\", \"mountpoint\":null, \"size\":\"4M\", \"uuid\":null, \"ro\":false, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"part\"},\n {\"name\":\"vda15\", \"fstype\":\"vfat\", \"maj:min\":\"252:15\", \"mountpoint\":\"/boot/efi\", \"size\":\"106M\", \"uuid\":\"26F2-56F9\", \"ro\":false, \"rm\":false, \"owner\":\"root\", \"group\":\"disk\", \"mode\":\"brw-rw----\", \"type\":\"part\"}\n ]\n }\n ]\n}\n")
command.to_json
{
"blockdevices" => [
{
"name" => "loop0",
"fstype" => "squashfs",
"maj:min" => "7:0",
"mountpoint" => "/snap/core18/2074" .. "owner" => "root",
"group" => "disk",
"mode" => "brw-rw----",
"type" => "loop"
},
{
"name" => "loop1",
"fstype" => "squashfs",
"maj:min" => "7:1",
"mountpoint" => "/snap/core18/2128" .. "owner" => "root",
"group" => "disk",
"mode" => "brw-rw----",
"type" => "loop"
},
{
"name" => "loop2",
"fstype" => "squashfs",
"maj:min" => "7:2",
"mountpoint" => "/snap/core20/1169" .. "owner" => "root",
"group" => "disk",
"mode" => "brw-rw----",
"type" => "loop"
}
]
}
prepared_command
Prepares command for running on a server. If a shell, user, environment variables were set, this will automatically add these.
command = Kanrisuru::Command.new("echo $VARIABLE")
command.prepared_command
"echo $VARIABLE"
command.remote_user = 'bob'
command.remote_shell = "/bin/bash"
command.remote_path = "/home/bob"
command.remote_env = "export VARIABLE=hello;"
command.prepared_command
"export VARIABLE=hello; sudo -u bob /bin/bash -c \"cd /home/bob && echo $VARIABLE\""
raw_command
Returns the raw command that is used to track all the fields, args appended.
command = Kanrisuru::Command.new("tar --restrict")
command.raw_command
"tar --restrict"
command.append_arg('-C', '/home/ubuntu/dir')
command.append_arg('-f', '/home/ubuntu/dir/file1.txt')
command.append_flag('-c')
command.raw_command
"tar --restrict -C /home/ubuntu/dir -f /home/ubuntu/dir/file1.txt -c"
handle_data
Callback handler to append output data to the command. This is stored in a raw result array.
command = Kanrisuru::Command.new("cat /var/log/syslog")
command.handle_data("lots of logs")
command.handle_data("lots of logs")
command.handle_data("lots of logs")
command.raw_result
["lots of logs", "lots of logs", "lots of logs"]
handle_status
Callback handler to set the exit status of the program run.
command = Kanrisuru::Command.new("pwd")
command.handle_status(0)
command.exit_status
0
handle_signal
Callback handler to set the signal from the ssh session.
Per net-ssh docs: “if the remote process died as a result of a signal being sent to it, the signal will be reported as a string in the data, via data.read_string. (Not all SSH servers support this channel request type.)”