Version: Unreleased

SSH API

SSH connection, remote execution, and file transfer helpers are available under ptool.ssh and p.ssh.

ptool.ssh.connect

ptool.ssh.connect(target_or_options) prepares an SSH connection handle backed by the system ssh command and returns a Connection object.

ssh must be available on PATH.

Arguments:

target_or_options (string|table, required):
- When a string is provided, it is treated as an SSH target.
- When a table is provided, it currently supports:
  - target (string, optional): SSH target string such as "[email protected]" or "[email protected]:2222".
  - host (string, optional): Hostname or IP address.
  - user (string, optional): SSH username. Defaults to $USER, or "root" if $USER is unavailable.
  - port (integer, optional): SSH port. Defaults to 22.
  - auth (table, optional): Authentication settings.
  - host_key (table, optional): Host key verification settings.
  - connect_timeout_ms (integer, optional): Timeout in milliseconds. Defaults to 10000.
  - keepalive_interval_ms (integer, optional): Keepalive interval in milliseconds.

Supported target string examples:

local a = ptool.ssh.connect("[email protected]")
local b = ptool.ssh.connect("[email protected]:2222")
local c = ptool.ssh.connect("[2001:db8::10]:2222")

auth fields:

private_key_file (string, optional): Path to a private key file.
private_key_passphrase (string, optional): Passphrase for the private key. This is currently not supported.
password (string, optional): Password-based authentication. This is currently not supported.

Authentication behavior:

If auth.private_key_file is provided, ptool invokes ssh with that key via -i and also sets IdentitiesOnly=yes.
If auth.private_key_passphrase or auth.password is provided, ptool.ssh.connect(...) fails because this API does not pass those secrets to the system ssh command.
Otherwise, authentication is delegated to the local OpenSSH setup, including settings and mechanisms such as IdentityFile, ProxyJump, ProxyCommand, ssh-agent, and certificates.
Relative key paths are resolved from the current ptool runtime directory, so they follow ptool.cd(...).
~ and ~/... are expanded in key paths.

host_key fields:

verify (string, optional): Host key verification mode. Supported values:
- "known_hosts": Verify against a known_hosts file (default).
- "ignore": Skip host key verification.
known_hosts_file (string, optional): Path to a known_hosts file. Used only when verify = "known_hosts".

Host key behavior:

If verify = "ignore", ptool invokes ssh with StrictHostKeyChecking=no and UserKnownHostsFile=/dev/null.
If verify = "known_hosts" and known_hosts_file is provided, ptool invokes ssh with StrictHostKeyChecking=yes and that UserKnownHostsFile.
If verify = "known_hosts" and known_hosts_file is omitted, or when host_key is omitted entirely, host key handling is delegated to the local OpenSSH configuration and defaults.
Relative known_hosts_file paths are resolved from the current ptool runtime directory.
~ and ~/... are expanded in known_hosts_file.
When known_hosts_file is provided explicitly, it overrides the default UserKnownHostsFile used by the local ssh command for this connection.

Example:

local ssh = ptool.ssh.connect({
  host = "example.com",
  user = "deploy",
  port = 22,
  auth = {
    private_key_file = "~/.ssh/id_ed25519",
  },
  host_key = {
    verify = "known_hosts",
  },
})

Connection

Connection represents an OpenSSH-backed connection handle returned by ptool.ssh.connect().

It is implemented as a Lua userdata.

Fields and methods:

Fields:
- conn.host (string)
- conn.user (string)
- conn.port (integer)
- conn.target (string)
Methods:
- conn:run(...) -> table
- conn:run_capture(...) -> table
- conn:path(path) -> RemotePath
- conn:exists(path) -> boolean
- conn:is_file(path) -> boolean
- conn:is_dir(path) -> boolean
- conn:upload(local_path, remote_path[, options]) -> table
- conn:download(remote_path, local_path[, options]) -> table
- conn:close() -> nil

run

Canonical API name: ptool.ssh.Connection:run.

conn:run(...) executes a remote command through the current SSH connection.

The following call forms are supported:

conn:run("hostname")
conn:run("echo", "hello world")
conn:run("echo", {"hello", "world"})
conn:run("hostname", { stdout = "capture" })
conn:run("echo", {"hello", "world"}, { stdout = "capture" })
conn:run({ cmd = "git", args = {"rev-parse", "HEAD"} })

Argument rules:

conn:run(cmdline): cmdline is sent as the remote command string.
conn:run(cmd, argsline): cmd is treated as the command, and argsline is split using shell-style (shlex) rules.
conn:run(cmd, args): cmd is a string and args is an array of strings. Arguments are shell-quoted before remote execution.
conn:run(cmdline, options): options overrides this invocation.
conn:run(cmd, args, options): options overrides this invocation.
conn:run(options): options is a table.
When the second argument is a table: if it is an array (consecutive integer keys 1..n), it is treated as args; otherwise it is treated as options.

When conn:run(options) is used, options currently supports:

cmd (string, required): The command name or executable path.
args (string[], optional): The argument list.
cwd (string, optional): Remote working directory. This is applied by prepending cd ... && to the generated remote shell command.
env (table, optional): Remote environment variables, where keys and values are strings. This is applied by prepending export ... && to the generated remote shell command.
stdin (string, optional): String sent to the remote process stdin.
echo (boolean, optional): Whether to echo the remote command before execution. Defaults to true.
check (boolean, optional): Whether to raise an error immediately when the exit status is not 0. Defaults to false.
stdout (string, optional): Stdout handling strategy. Supported values:
- "inherit": Inherit to the current terminal (default).
- "capture": Capture into res.stdout.
- "null": Discard the output.
stderr (string, optional): Stderr handling strategy. Supported values:
- "inherit": Inherit to the current terminal (default).
- "capture": Capture into res.stderr.
- "null": Discard the output.

When the shortcut forms are used, the options table supports only:

stdin (string, optional): String sent to the remote process stdin.
echo (boolean, optional): Whether to echo the remote command before execution. Defaults to true.
check (boolean, optional): Whether to raise an error immediately when the exit status is not 0. Defaults to false.
stdout (string, optional): Stdout handling strategy. Supported values:
- "inherit": Inherit to the current terminal (default).
- "capture": Capture into res.stdout.
- "null": Discard the output.
stderr (string, optional): Stderr handling strategy. Supported values:
- "inherit": Inherit to the current terminal (default).
- "capture": Capture into res.stderr.
- "null": Discard the output.

Return value rules:

A table is always returned with the following fields:
- ok (boolean): Whether the remote exit status is 0.
- code (integer|nil): The remote exit status. If the remote process exits by signal, this is nil.
- target (string): The SSH target string in the form user@host:port.
- stdout (string, optional): Present when stdout = "capture".
- stderr (string, optional): Present when stderr = "capture".
- assert_ok(self) (function): Raises an error when ok = false.

Example:

local ssh = ptool.ssh.connect("[email protected]")

local res = ssh:run("uname -a", { stdout = "capture" })
print(res.target)
print(res.stdout)
local res2 = ssh:run({
  cmd = "git",
  args = {"rev-parse", "HEAD"},
  cwd = "/srv/app",
  env = {
    FOO = "bar",
  },
  stdout = "capture",
  check = true,
})

print(res2.stdout)

run_capture

Canonical API name: ptool.ssh.Connection:run_capture.

conn:run_capture(...) executes a remote command through the current SSH connection.

It accepts the same call forms, argument rules, return value rules, and options as conn:run(...).

The difference is only the default stream handling:

stdout defaults to "capture".
stderr defaults to "capture".

You can still override either field explicitly in options.

Example:

local ssh = ptool.ssh.connect("[email protected]")

local res = ssh:run_capture("uname -a")
print(res.stdout)

local res2 = ssh:run_capture({
  cmd = "sh",
  args = {"-c", "printf 'out'; printf 'err' >&2"},
  cwd = "/srv/app",
})
print(res2.stdout)
print(res2.stderr)

local res3 = ssh:run_capture("echo hello", {
  stderr = "inherit",
})
print(res3.stdout)

path

Canonical API name: ptool.ssh.Connection:path.

conn:path(path) creates a reusable RemotePath object bound to the current SSH connection.

path (string, required): The remote path.
Returns: A RemotePath object that can be passed to conn:upload(...), conn:download(...), and ptool.fs.copy(...).

Example:

local ssh = ptool.ssh.connect("[email protected]")
local remote_release = ssh:path("/srv/app/releases/current.tar.gz")

ssh:download(remote_release, "./tmp/current.tar.gz")

exists

Canonical API name: ptool.ssh.Connection:exists.

conn:exists(path) checks whether a remote path exists.

path (string|remote path, required): The remote path to check. It can be a string or a value created by conn:path(...).
Returns: true when the remote path exists, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")

print(ssh:exists("/srv/app"))
print(ssh:path("/srv/app/releases/current.tar.gz"):exists())

is_file

Canonical API name: ptool.ssh.Connection:is_file.

conn:is_file(path) checks whether a remote path exists and is a regular file.

path (string|remote path, required): The remote path to check. It can be a string or a value created by conn:path(...).
Returns: true when the remote path is a file, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local remote_tarball = ssh:path("/srv/app/releases/current.tar.gz")

if ssh:is_file(remote_tarball) then
  print("release tarball exists")
end

is_dir

Canonical API name: ptool.ssh.Connection:is_dir.

conn:is_dir(path) checks whether a remote path exists and is a directory.

path (string|remote path, required): The remote path to check. It can be a string or a value created by conn:path(...).
Returns: true when the remote path is a directory, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local releases = ssh:path("/srv/app/releases")

if releases:is_dir() then
  print("releases directory is ready")
end

upload

Canonical API name: ptool.ssh.Connection:upload.

conn:upload(local_path, remote_path[, options]) uploads a local file or directory to the remote host.

local_path (string, required): The local file or directory to upload.
remote_path (string|remote path, required): The destination path on the remote host. It can be a string or a value created by conn:path(...).
options (table, optional): Transfer options.
Returns: A table with the following fields:
- bytes (integer): The number of regular-file bytes uploaded. When a directory is uploaded, this is the sum of the uploaded file sizes.
- from (string): The local source path.
- to (string): The remote destination path.

Supported transfer options:

parents (boolean, optional): Create the parent directory of remote_path before uploading. Defaults to false.
overwrite (boolean, optional): Whether an existing destination file may be replaced. Defaults to true.
echo (boolean, optional): Whether to print the transfer before executing it. Defaults to false.

Directory behavior:

When local_path is a file, the behavior is unchanged.
When local_path is a directory and remote_path does not exist, remote_path becomes the destination directory root.
When local_path is a directory and remote_path already exists as a directory, the source directory is created under it using the source directory basename.
overwrite = false rejects an already-existing destination directory for the final directory root.
Directory uploads require tar to be available on the remote host.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local remote_tarball = ssh:path("/srv/app/releases/current.tar.gz")

local res = ssh:upload("./dist/app.tar.gz", remote_tarball, {
  parents = true,
  overwrite = true,
  echo = true,
})

print(res.bytes)
print(res.to)

Directory example:

local ssh = ptool.ssh.connect("[email protected]")

local res = ssh:upload("./dist/assets", "/srv/app/releases", {
  parents = true,
  overwrite = true,
  echo = true,
})

print(res.bytes)
print(res.to) -- [email protected]:22:/srv/app/releases

download

Canonical API name: ptool.ssh.Connection:download.

conn:download(remote_path, local_path[, options]) downloads a remote file or directory to a local path.

remote_path (string|remote path, required): The source path on the remote host. It can be a string or a value created by conn:path(...).
local_path (string, required): The local destination path.
options (table, optional): Transfer options.
Returns: A table with the following fields:
- bytes (integer): The number of regular-file bytes downloaded. When a directory is downloaded, this is the sum of the downloaded file sizes.
- from (string): The remote source path.
- to (string): The local destination path.

Supported transfer options:

parents (boolean, optional): Create the parent directory of local_path before downloading. Defaults to false.
overwrite (boolean, optional): Whether an existing destination file may be replaced. Defaults to true.
echo (boolean, optional): Whether to print the transfer before executing it. Defaults to false.

Directory behavior:

When remote_path is a file, the behavior is unchanged.
When remote_path is a directory and local_path does not exist, local_path becomes the destination directory root.
When remote_path is a directory and local_path already exists as a directory, the remote source directory is created under it using the remote directory basename.
overwrite = false rejects an already-existing destination directory for the final directory root.
Directory downloads require tar to be available on the remote host.

Example:

local ssh = ptool.ssh.connect("[email protected]")

local res = ssh:download("/srv/app/logs/app.log", "./tmp/app.log", {
  parents = true,
  overwrite = false,
  echo = true,
})

print(res.bytes)
print(res.from)

Directory example:

local ssh = ptool.ssh.connect("[email protected]")

local res = ssh:download("/srv/app/releases/assets", "./tmp/releases", {
  parents = true,
  overwrite = true,
  echo = true,
})

print(res.bytes)
print(res.from)

close

Canonical API name: ptool.ssh.Connection:close.

conn:close() closes the SSH connection handle.

Behavior:

After closing, the connection can no longer be used.
Closing an already-closed connection is allowed and has no effect.

Example:

local ssh = ptool.ssh.connect("[email protected]")
ssh:close()

RemotePath

RemotePath represents a remote path bound to a Connection and returned by conn:path(path).

It is implemented as a Lua userdata.

Methods:

remote:exists() -> boolean
remote:is_file() -> boolean
remote:is_dir() -> boolean

exists

remote:exists() checks whether the remote path exists.

Returns: true when the remote path exists, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local remote_release = ssh:path("/srv/app/releases/current.tar.gz")

print(remote_release:exists())

is_file

remote:is_file() checks whether the remote path exists and is a regular file.

Returns: true when the remote path is a file, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local remote_tarball = ssh:path("/srv/app/releases/current.tar.gz")

if remote_tarball:is_file() then
  print("release tarball exists")
end

is_dir

remote:is_dir() checks whether the remote path exists and is a directory.

Returns: true when the remote path is a directory, otherwise false.

Example:

local ssh = ptool.ssh.connect("[email protected]")
local releases = ssh:path("/srv/app/releases")

if releases:is_dir() then
  print("releases directory is ready")
end

ptool.ssh.connect​

Connection​

run​

run_capture​

path​

exists​

is_file​

is_dir​

upload​

download​

close​

RemotePath​

exists​

is_file​

is_dir​

ptool.ssh.connect

Connection

run

run_capture

path

exists

is_file

is_dir

upload

download

close

RemotePath

exists

is_file

is_dir