parsl.channels.SSHChannel

class parsl.channels.SSHChannel(hostname, username=None, password=None, script_dir=None, envs=None, gssapi_auth=False, skip_auth=False, port=22, key_filename=None, host_keys_filename=None)

SSH persistent channel. This enables remote execution on sites accessible via ssh. It is assumed that the user has setup host keys so as to ssh to the remote host. Which goes to say that the following test on the commandline should work:

>>> ssh <username>@<hostname>

__init__(hostname, username=None, password=None, script_dir=None, envs=None, gssapi_auth=False, skip_auth=False, port=22, key_filename=None, host_keys_filename=None)

Initialize a persistent connection to the remote system. We should know at this point whether ssh connectivity is possible

Parameters

hostname (-) – Hostname

KWargs:

• username (string) : Username on remote system

• password (string) : Password for remote system

• port : The port designated for the ssh connection. Default is 22.

• script_dir (string) : Full path to a script dir where generated scripts could be sent to.

• envs (dict) : A dictionary of environment variables to be set when executing commands

• key_filename (string or list): the filename, or list of filenames, of optional private key(s)

Raises:

Methods

__init__(hostname[, username, password, ...])	Initialize a persistent connection to the remote system.
abspath(path)	Return the absolute path on the remote side.
close()	Closes the channel.
execute_wait(cmd[, walltime, envs])	Synchronously execute a commandline string on the shell.
isdir(path)	Return true if the path refers to an existing directory.
makedirs(path[, mode, exist_ok])	Create a directory on the remote side.
prepend_envs(cmd[, env])
pull_file(remote_source, local_dir)	Transport file on the remote side to a local directory
push_file(local_source, remote_dir)	Transport a local file to a directory on a remote machine

Attributes

script_dir

This is a property.

abspath(path)

Return the absolute path on the remote side.

Parameters

path (str) – Path for which the absolute path will be returned.

close()

Closes the channel. Clean out any auth credentials.

Parameters

None –

Returns

Bool

execute_wait(cmd, walltime=2, envs={})

Synchronously execute a commandline string on the shell.

Parameters

• cmd (-) – Commandline string to execute

• walltime (-) – walltime in seconds

Kwargs:

• envs (dict) : Dictionary of env variables

Returns

Return code from the execution, -1 on fail - stdout : stdout string - stderr : stderr string

Return type

• retcode

Raises: None.

isdir(path)

Return true if the path refers to an existing directory.

Parameters

path (str) – Path of directory on the remote side to check.

makedirs(path, mode=448, exist_ok=False)

Create a directory on the remote side.

If intermediate directories do not exist, they will be created.

Parameters

• path (str) – Path of directory on the remote side to create.

• mode (int) – Permissions (posix-style) for the newly-created directory.

• exist_ok (bool) – If False, raise an OSError if the target directory already exists.

prepend_envs(cmd, env={})

pull_file(remote_source, local_dir)

Transport file on the remote side to a local directory

Parameters

• remote_source (-) – remote_source

• local_dir (-) – Local directory to copy to

Returns

Local path to file

Return type

• str

Raises

• - FileExists – Name collision at local directory.

• - FileCopyException – FileCopy failed.

push_file(local_source, remote_dir)

Transport a local file to a directory on a remote machine

Parameters

• local_source (-) – Path

• remote_dir (-) – Remote path

Returns

Path to copied file on remote machine

Return type

• str

Raises

• - BadScriptPath – if script path on the remote side is bad

• - BadPermsScriptPath – You do not have perms to make the channel script dir

• - FileCopyException – FileCopy failed.

property script_dir

This is a property. Returns the directory assigned for storing all internal scripts such as scheduler submit scripts. This is usually where error logs from the scheduler would reside on the channel destination side.

Parameters

None (-) –

Returns

• Channel script dir