Frequently Asked Questions¶

How do I get the name of the current host?¶

The currently executing host can be fetched from the host context variable. If you need the hostname the server.Hostname fact can be used to get that:

# Get the name of the host as defined in the inventory
from pyinfra import host
name = host.name

# Get the actual current hostname from the host
from pyinfra.facts.server import Hostname
hostname = host.get_fact(Hostname)

How do I use sudo in an operation?¶

Sudo is controlled by one of the privilege and user escalation arguments, there are a number of additional arguments to control sudo execution:

apt.packages(
    packages=["iftop"],
    _sudo=True,
    _sudo_user="someuser",    # sudo to this user
    _use_sudo_login=True,     # use a login shell when sudo-ing
    _preserve_sudo_env=True,  # preserve the environment when sudo-ing
)

How do I chmod or chown a file/directory/link?¶

Use the LINK files.file, files.directory or files.link operations to set the permissions and ownership of files, directories & links:

files.file(
    path="/etc/default/elasticsearch",
    user="pyinfra",
    group="pyinfra",
    mode=644,
)

How do I handle unreliable operations or network issues?¶

Use the retry behavior arguments to automatically retry failed operations. This is especially useful for network operations or services that may be temporarily unavailable:

# Retry a network operation up to 3 times
server.shell(
    name="Download file with retries",
    commands=["wget https://example.com/file.zip"],
    _retries=3,
    _retry_delay=5,  # wait 5 seconds between retries
)

# Use custom retry logic for specific error conditions
def should_retry_download(output_data):
    # Retry only on temporary network errors, not permanent failures
    stderr_text = " ".join(output_data["stderr_lines"]).lower()
    temporary_errors = ["timeout", "connection refused", "temporary failure"]
    return any(error in stderr_text for error in temporary_errors)

server.shell(
    name="Download with smart retry logic",
    commands=["wget https://example.com/large-file.zip"],
    _retries=3,
    _retry_until=should_retry_download,
)