From 600b870b399feb9e072748e07ea223556261fbe7 Mon Sep 17 00:00:00 2001 From: Chris Lalos Date: Thu, 10 Feb 2022 15:49:38 -0600 Subject: Shell script handlers by freq (#1166) Handlers for per-boot/per-instance/per-once multipart MIME Add handlers for adding scripts to userdata that can be run at various frequencies. Scripts of type x-shellscript-per-boot, x-shellscript-per-instance, or x-shellscript-per-once can be added to a multipart MIME userdata message as part of instance userdata. These scripts will then be added to the appropriate per-boot, per-instance, or per-once directory in /var/lib/cloud/scripts/ during processing of userdata. --- cloudinit/handlers/shell_script_by_frequency.py | 62 +++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 cloudinit/handlers/shell_script_by_frequency.py (limited to 'cloudinit/handlers/shell_script_by_frequency.py') diff --git a/cloudinit/handlers/shell_script_by_frequency.py b/cloudinit/handlers/shell_script_by_frequency.py new file mode 100644 index 00000000..923cca57 --- /dev/null +++ b/cloudinit/handlers/shell_script_by_frequency.py @@ -0,0 +1,62 @@ +import os + +from cloudinit import log, util +from cloudinit.handlers import Handler +from cloudinit.settings import PER_ALWAYS, PER_INSTANCE, PER_ONCE + +LOG = log.getLogger(__name__) + +# cloudinit/settings.py defines PER_*** frequency constants. It makes sense to +# use them here, instead of hardcodes, and map them to the 'per-***' frequency- +# specific folders in /v/l/c/scripts. It might make sense to expose this at a +# higher level or in a more general module -- eg maybe in cloudinit/settings.py +# itself -- but for now it's here. +path_map = { + PER_ALWAYS: "per-boot", + PER_INSTANCE: "per-instance", + PER_ONCE: "per-once", +} + + +def get_mime_type_by_frequency(freq): + mime_type = f"text/x-shellscript-{path_map[freq]}" + return mime_type + + +def get_script_folder_by_frequency(freq, scripts_dir): + """Return the frequency-specific subfolder for a given frequency constant + and parent folder.""" + freqPath = path_map[freq] + folder = os.path.join(scripts_dir, freqPath) + return folder + + +def write_script_by_frequency(script_path, payload, frequency, scripts_dir): + """Given a filename, a payload, a frequency, and a scripts folder, write + the payload to the correct frequency-specific path""" + filename = os.path.basename(script_path) + filename = util.clean_filename(filename) + folder = get_script_folder_by_frequency(frequency, scripts_dir) + path = os.path.join(folder, filename) + payload = util.dos2unix(payload) + util.write_file(path, payload, 0o700) + + +class ShellScriptByFreqPartHandler(Handler): + """Common base class for the frequency-specific script handlers.""" + + def __init__(self, script_frequency, paths, **_kwargs): + Handler.__init__(self, PER_ALWAYS) + self.prefixes = [get_mime_type_by_frequency(script_frequency)] + self.script_frequency = script_frequency + self.scripts_dir = paths.get_cpath("scripts") + if "script_path" in _kwargs: + self.scripts_dir = paths.get_cpath(_kwargs["script_path"]) + + def handle_part(self, data, ctype, script_path, payload, frequency): + if script_path is not None: + filename = os.path.basename(script_path) + filename = util.clean_filename(filename) + write_script_by_frequency( + script_path, payload, self.script_frequency, self.scripts_dir + ) -- cgit v1.2.3