Edit File: ec2_utils.py
# Copyright (C) 2012 Yahoo! Inc. # Copyright (C) 2014 Amazon.com, Inc. or its affiliates. # # Author: Joshua Harlow <harlowja@yahoo-inc.com> # Author: Andrew Jorgensen <ajorgens@amazon.com> # # This file is part of cloud-init. See LICENSE file for license information. import functools import json from cloudinit import log as logging from cloudinit import url_helper from cloudinit import util LOG = logging.getLogger(__name__) SKIP_USERDATA_CODES = frozenset([url_helper.NOT_FOUND]) class MetadataLeafDecoder(object): """Decodes a leaf blob into something meaningful.""" def _maybe_json_object(self, text): if not text: return False text = text.strip() if text.startswith("{") and text.endswith("}"): return True return False def __call__(self, field, blob): if not blob: return '' try: blob = util.decode_binary(blob) except UnicodeDecodeError: return blob if self._maybe_json_object(blob): try: # Assume it's json, unless it fails parsing... return json.loads(blob) except (ValueError, TypeError) as e: LOG.warning("Field %s looked like a json object, but it" " was not: %s", field, e) if blob.find("\n") != -1: return blob.splitlines() return blob # See: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ # ec2-instance-metadata.html class MetadataMaterializer(object): def __init__(self, blob, base_url, caller, leaf_decoder=None): self._blob = blob self._md = None self._base_url = base_url self._caller = caller if leaf_decoder is None: self._leaf_decoder = MetadataLeafDecoder() else: self._leaf_decoder = leaf_decoder def _parse(self, blob): leaves = {} children = [] blob = util.decode_binary(blob) if not blob: return (leaves, children) def has_children(item): if item.endswith("/"): return True else: return False def get_name(item): if item.endswith("/"): return item.rstrip("/") return item for field in blob.splitlines(): field = field.strip() field_name = get_name(field) if not field or not field_name: continue # Don't materialize credentials if field_name == 'security-credentials': continue if has_children(field): if field_name not in children: children.append(field_name) else: contents = field.split("=", 1) resource = field_name if len(contents) > 1: # What a PITA... (ident, sub_contents) = contents ident = util.safe_int(ident) if ident is not None: resource = "%s/openssh-key" % (ident) field_name = sub_contents leaves[field_name] = resource return (leaves, children) def materialize(self): if self._md is not None: return self._md self._md = self._materialize(self._blob, self._base_url) return self._md def _materialize(self, blob, base_url): (leaves, children) = self._parse(blob) child_contents = {} for c in children: child_url = url_helper.combine_url(base_url, c) if not child_url.endswith("/"): child_url += "/" child_blob = self._caller(child_url) child_contents[c] = self._materialize(child_blob, child_url) leaf_contents = {} for (field, resource) in leaves.items(): leaf_url = url_helper.combine_url(base_url, resource) leaf_blob = self._caller(leaf_url) leaf_contents[field] = self._leaf_decoder(field, leaf_blob) joined = {} joined.update(child_contents) for field in leaf_contents.keys(): if field in joined: LOG.warning("Duplicate key found in results from %s", base_url) else: joined[field] = leaf_contents[field] return joined def skip_retry_on_codes(status_codes, _request_args, cause): """Returns False if cause.code is in status_codes.""" return cause.code not in status_codes def get_instance_userdata(api_version='latest', metadata_address='http://169.254.169.254', ssl_details=None, timeout=5, retries=5, headers_cb=None, headers_redact=None, exception_cb=None): ud_url = url_helper.combine_url(metadata_address, api_version) ud_url = url_helper.combine_url(ud_url, 'user-data') user_data = '' try: if not exception_cb: # It is ok for userdata to not exist (thats why we are stopping if # NOT_FOUND occurs) and just in that case returning an empty # string. exception_cb = functools.partial(skip_retry_on_codes, SKIP_USERDATA_CODES) response = url_helper.read_file_or_url( ud_url, ssl_details=ssl_details, timeout=timeout, retries=retries, exception_cb=exception_cb, headers_cb=headers_cb, headers_redact=headers_redact) user_data = response.contents except url_helper.UrlError as e: if e.code not in SKIP_USERDATA_CODES: util.logexc(LOG, "Failed fetching userdata from url %s", ud_url) except Exception: util.logexc(LOG, "Failed fetching userdata from url %s", ud_url) return user_data def _get_instance_metadata(tree, api_version='latest', metadata_address='http://169.254.169.254', ssl_details=None, timeout=5, retries=5, leaf_decoder=None, headers_cb=None, headers_redact=None, exception_cb=None): md_url = url_helper.combine_url(metadata_address, api_version, tree) caller = functools.partial( url_helper.read_file_or_url, ssl_details=ssl_details, timeout=timeout, retries=retries, headers_cb=headers_cb, headers_redact=headers_redact, exception_cb=exception_cb) def mcaller(url): return caller(url).contents try: response = caller(md_url) materializer = MetadataMaterializer(response.contents, md_url, mcaller, leaf_decoder=leaf_decoder) md = materializer.materialize() if not isinstance(md, (dict)): md = {} return md except Exception: util.logexc(LOG, "Failed fetching %s from url %s", tree, md_url) return {} def get_instance_metadata(api_version='latest', metadata_address='http://169.254.169.254', ssl_details=None, timeout=5, retries=5, leaf_decoder=None, headers_cb=None, headers_redact=None, exception_cb=None): # Note, 'meta-data' explicitly has trailing /. # this is required for CloudStack (LP: #1356855) return _get_instance_metadata(tree='meta-data/', api_version=api_version, metadata_address=metadata_address, ssl_details=ssl_details, timeout=timeout, retries=retries, leaf_decoder=leaf_decoder, headers_redact=headers_redact, headers_cb=headers_cb, exception_cb=exception_cb) def get_instance_identity(api_version='latest', metadata_address='http://169.254.169.254', ssl_details=None, timeout=5, retries=5, leaf_decoder=None, headers_cb=None, headers_redact=None, exception_cb=None): return _get_instance_metadata(tree='dynamic/instance-identity', api_version=api_version, metadata_address=metadata_address, ssl_details=ssl_details, timeout=timeout, retries=retries, leaf_decoder=leaf_decoder, headers_redact=headers_redact, headers_cb=headers_cb, exception_cb=exception_cb) # vi: ts=4 expandtab