name : cc_write_files.py # Copyright (C) 2012 Yahoo! Inc. # # Author: Joshua Harlow <harlowja@yahoo-inc.com> # # This file is part of cloud-init. See LICENSE file for license information. """Write Files: write arbitrary files""" import base64 import logging import os from textwrap import dedent from cloudinit import util from cloudinit.cloud import Cloud from cloudinit.config import Config from cloudinit.config.schema import MetaSchema, get_meta_doc from cloudinit.settings import PER_INSTANCE DEFAULT_PERMS = 0o644 DEFAULT_DEFER = False TEXT_PLAIN_ENC = "text/plain" LOG = logging.getLogger(__name__) meta: MetaSchema = { "id": "cc_write_files", "name": "Write Files", "title": "write arbitrary files", "description": dedent( """\ Write out arbitrary content to files, optionally setting permissions. Parent folders in the path are created if absent. Content can be specified in plain text or binary. Data encoded with either base64 or binary gzip data can be specified and will be decoded before being written. For empty file creation, content can be omitted. .. note:: If multiline data is provided, care should be taken to ensure that it follows yaml formatting standards. To specify binary data, use the yaml option ``!!binary`` .. note:: Do not write files under /tmp during boot because of a race with systemd-tmpfiles-clean that can cause temp files to get cleaned during the early boot process. Use /run/somedir instead to avoid race LP:1707222. .. warning:: Existing files will be overridden.""" ), "distros": ["all"], "examples": [ dedent( """\ # Write out base64 encoded content to /etc/sysconfig/selinux write_files: - encoding: b64 content: CiMgVGhpcyBmaWxlIGNvbnRyb2xzIHRoZSBzdGF0ZSBvZiBTRUxpbnV4... owner: root:root path: /etc/sysconfig/selinux permissions: '0644' """ ), dedent( """\ # Appending content to an existing file write_files: - content: | 15 * * * * root ship_logs path: /etc/crontab append: true """ ), dedent( """\ # Provide gzipped binary content write_files: - encoding: gzip content: !!binary | H4sIAIDb/U8C/1NW1E/KzNMvzuBKTc7IV8hIzcnJVyjPL8pJ4QIA6N+MVxsAAAA= path: /usr/bin/hello permissions: '0755' """ ), dedent( """\ # Create an empty file on the system write_files: - path: /root/CLOUD_INIT_WAS_HERE """ ), dedent( """\ # Defer writing the file until after the package (Nginx) is # installed and its user is created alongside write_files: - path: /etc/nginx/conf.d/example.com.conf content: | server { server_name example.com; listen 80; root /var/www; location / { try_files $uri $uri/ $uri.html =404; } } owner: 'nginx:nginx' permissions: '0640' defer: true """ ), ], "frequency": PER_INSTANCE, "activate_by_schema_keys": ["write_files"], } __doc__ = get_meta_doc(meta) def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None: file_list = cfg.get("write_files", []) filtered_files = [ f for f in file_list if not util.get_cfg_option_bool(f, "defer", DEFAULT_DEFER) ] if not filtered_files: LOG.debug( "Skipping module named %s," " no/empty 'write_files' key in configuration", name, ) return write_files(name, filtered_files, cloud.distro.default_owner) def canonicalize_extraction(encoding_type): if not encoding_type: encoding_type = "" encoding_type = encoding_type.lower().strip() if encoding_type in ["gz", "gzip"]: return ["application/x-gzip"] if encoding_type in ["gz+base64", "gzip+base64", "gz+b64", "gzip+b64"]: return ["application/base64", "application/x-gzip"] # Yaml already encodes binary data as base64 if it is given to the # yaml file as binary, so those will be automatically decoded for you. # But the above b64 is just for people that are more 'comfortable' # specifying it manually (which might be a possibility) if encoding_type in ["b64", "base64"]: return ["application/base64"] if encoding_type == TEXT_PLAIN_ENC: return [TEXT_PLAIN_ENC] if encoding_type: LOG.warning( "Unknown encoding type %s, assuming %s", encoding_type, TEXT_PLAIN_ENC, ) return [TEXT_PLAIN_ENC] def write_files(name, files, owner: str): if not files: return for (i, f_info) in enumerate(files): path = f_info.get("path") if not path: LOG.warning( "No path provided to write for entry %s in module %s", i + 1, name, ) continue path = os.path.abspath(path) extractions = canonicalize_extraction(f_info.get("encoding")) contents = extract_contents(f_info.get("content", ""), extractions) (u, g) = util.extract_usergroup(f_info.get("owner", owner)) perms = decode_perms(f_info.get("permissions"), DEFAULT_PERMS) omode = "ab" if util.get_cfg_option_bool(f_info, "append") else "wb" util.write_file( path, contents, omode=omode, mode=perms, user=u, group=g ) util.chownbyname(path, u, g) def decode_perms(perm, default): if perm is None: return default try: if isinstance(perm, (int, float)): # Just 'downcast' it (if a float) return int(perm) else: # Force to string and try octal conversion return int(str(perm), 8) except (TypeError, ValueError): reps = [] for r in (perm, default): try: reps.append("%o" % r) except TypeError: reps.append("%r" % r) LOG.warning("Undecodable permissions %s, returning default %s", *reps) return default def extract_contents(contents, extraction_types): result = contents for t in extraction_types: if t == "application/x-gzip": result = util.decomp_gzip(result, quiet=False, decode=False) elif t == "application/base64": result = base64.b64decode(result) elif t == TEXT_PLAIN_ENC: pass return result