# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
import codecs
import concurrent.futures
import email.message
import errno
import os
import os.path
import re
import shutil
import ssl
import sys
import traceback
import urllib.parse
from html.parser import HTMLParser
from pathlib import Path, PurePosixPath
from typing import IO, Dict, Iterable, List, Optional, Set, Union
from urllib.error import HTTPError, URLError
from urllib.request import HTTPSHandler, Request, build_opener
import llnl.url
from llnl.util import lang, tty
from llnl.util.filesystem import mkdirp, rename, working_dir
import spack.config
import spack.error
import spack.util.path
import spack.util.url as url_util
from .executable import CommandNotFoundError, which
from .gcs import GCSBlob, GCSBucket, GCSHandler
from .s3 import UrllibS3Handler, get_s3_session
[docs]
class DetailedHTTPError(HTTPError):
def __init__(
self, req: Request, code: int, msg: str, hdrs: email.message.Message, fp: Optional[IO]
) -> None:
self.req = req
super().__init__(req.get_full_url(), code, msg, hdrs, fp)
def __str__(self):
# Note: HTTPError, is actually a kind of non-seekable response object, so
# best not to read the response body here (even if it may include a human-readable
# error message).
# Note: use self.filename, not self.url, because the latter requires fp to be an
# IO object, which is not the case after unpickling.
return f"{self.req.get_method()} {self.filename} returned {self.code}: {self.msg}"
def __reduce__(self):
# fp is an IO object and not picklable, the rest should be.
return DetailedHTTPError, (self.req, self.code, self.msg, self.hdrs, None)
[docs]
class SpackHTTPDefaultErrorHandler(urllib.request.HTTPDefaultErrorHandler):
[docs]
def http_error_default(self, req, fp, code, msg, hdrs):
raise DetailedHTTPError(req, code, msg, hdrs, fp)
dbg_msg_no_ssl_cert_config = (
"config:ssl_certs not in configuration. "
"Default cert configuation and environment will be used."
)
[docs]
def urllib_ssl_cert_handler():
"""context for configuring ssl during urllib HTTPS operations"""
custom_cert_var = spack.config.get("config:ssl_certs")
if custom_cert_var:
# custom certs will be a location, so expand env variables, paths etc
certs = spack.util.path.canonicalize_path(custom_cert_var)
tty.debug("URLLIB: Looking for custom SSL certs at {}".format(certs))
if os.path.isfile(certs):
tty.debug("URLLIB: Custom SSL certs file found at {}".format(certs))
return ssl.create_default_context(cafile=certs)
elif os.path.isdir(certs):
tty.debug("URLLIB: Custom SSL certs directory found at {}".format(certs))
return ssl.create_default_context(capath=certs)
else:
tty.debug("URLLIB: Custom SSL certs not found")
return ssl.create_default_context()
else:
tty.debug(dbg_msg_no_ssl_cert_config)
return ssl.create_default_context()
# curl requires different strategies for custom certs at runtime depending on if certs
# are stored as a file or a directory
[docs]
def append_curl_env_for_ssl_certs(curl):
"""
configure curl to use custom certs in a file at run time
see: https://curl.se/docs/sslcerts.html item 4
"""
custom_cert_var = spack.config.get("config:ssl_certs")
if custom_cert_var:
# custom certs will be a location, so expand env variables, paths etc
certs = spack.util.path.canonicalize_path(custom_cert_var)
tty.debug("CURL: Looking for custom SSL certs file at {}".format(certs))
if os.path.isfile(certs):
tty.debug(
"CURL: Configuring curl to use custom"
" certs from {} by setting "
"CURL_CA_BUNDLE".format(certs)
)
curl.add_default_env("CURL_CA_BUNDLE", certs)
elif os.path.isdir(certs):
tty.warn(
"CURL config:ssl_certs"
" is a directory but cURL only supports files. Default certs will be used instead."
)
else:
tty.debug(
"CURL config:ssl_certs "
"resolves to {}. This is not a file so default certs will be used.".format(certs)
)
else:
tty.debug(dbg_msg_no_ssl_cert_config)
def _urlopen():
s3 = UrllibS3Handler()
gcs = GCSHandler()
error_handler = SpackHTTPDefaultErrorHandler()
# One opener with HTTPS ssl enabled
with_ssl = build_opener(
s3, gcs, HTTPSHandler(context=urllib_ssl_cert_handler()), error_handler
)
# One opener with HTTPS ssl disabled
without_ssl = build_opener(
s3, gcs, HTTPSHandler(context=ssl._create_unverified_context()), error_handler
)
# And dynamically dispatch based on the config:verify_ssl.
def dispatch_open(fullurl, data=None, timeout=None):
opener = with_ssl if spack.config.get("config:verify_ssl", True) else without_ssl
timeout = timeout or spack.config.get("config:connect_timeout", 10)
return opener.open(fullurl, data, timeout)
return dispatch_open
#: Dispatches to the correct OpenerDirector.open, based on Spack configuration.
urlopen = lang.Singleton(_urlopen)
#: User-Agent used in Request objects
SPACK_USER_AGENT = "Spackbot/{0}".format(spack.spack_version)
# Also, HTMLParseError is deprecated and never raised.
[docs]
class HTMLParseError(Exception):
pass
[docs]
class LinkParser(HTMLParser):
"""This parser just takes an HTML page and strips out the hrefs on the
links. Good enough for a really simple spider."""
def __init__(self):
super().__init__()
self.links = []
[docs]
def handle_starttag(self, tag, attrs):
if tag == "a":
for attr, val in attrs:
if attr == "href":
self.links.append(val)
[docs]
def read_from_url(url, accept_content_type=None):
if isinstance(url, str):
url = urllib.parse.urlparse(url)
# Timeout in seconds for web requests
request = Request(url.geturl(), headers={"User-Agent": SPACK_USER_AGENT})
try:
response = urlopen(request)
except URLError as err:
raise SpackWebError("Download failed: {}".format(str(err)))
if accept_content_type:
try:
content_type = get_header(response.headers, "Content-type")
reject_content_type = not content_type.startswith(accept_content_type)
except KeyError:
content_type = None
reject_content_type = True
if reject_content_type:
msg = "ignoring page {}".format(url.geturl())
if content_type:
msg += " with content type {}".format(content_type)
tty.debug(msg)
return None, None, None
return response.geturl(), response.headers, response
[docs]
def push_to_url(local_file_path, remote_path, keep_original=True, extra_args=None):
remote_url = urllib.parse.urlparse(remote_path)
if remote_url.scheme == "file":
remote_file_path = url_util.local_file_path(remote_url)
mkdirp(os.path.dirname(remote_file_path))
if keep_original:
shutil.copy(local_file_path, remote_file_path)
else:
try:
rename(local_file_path, remote_file_path)
except OSError as e:
if e.errno == errno.EXDEV:
# NOTE(opadron): The above move failed because it crosses
# filesystem boundaries. Copy the file (plus original
# metadata), and then delete the original. This operation
# needs to be done in separate steps.
shutil.copy2(local_file_path, remote_file_path)
os.remove(local_file_path)
else:
raise
elif remote_url.scheme == "s3":
if extra_args is None:
extra_args = {}
remote_path = remote_url.path
while remote_path.startswith("/"):
remote_path = remote_path[1:]
s3 = get_s3_session(remote_url, method="push")
s3.upload_file(local_file_path, remote_url.netloc, remote_path, ExtraArgs=extra_args)
if not keep_original:
os.remove(local_file_path)
elif remote_url.scheme == "gs":
gcs = GCSBlob(remote_url)
gcs.upload_to_blob(local_file_path)
if not keep_original:
os.remove(local_file_path)
else:
raise NotImplementedError(f"Unrecognized URL scheme: {remote_url.scheme}")
[docs]
def base_curl_fetch_args(url, timeout=0):
"""Return the basic fetch arguments typically used in calls to curl.
The arguments include those for ensuring behaviors such as failing on
errors for codes over 400, printing HTML headers, resolving 3xx redirects,
status or failure handling, and connection timeouts.
It also uses the following configuration option to set an additional
argument as needed:
* config:connect_timeout (int): connection timeout
* config:verify_ssl (str): Perform SSL verification
Arguments:
url (str): URL whose contents will be fetched
timeout (int): Connection timeout, which is only used if higher than
config:connect_timeout
Returns (list): list of argument strings
"""
curl_args = [
"-f", # fail on >400 errors
"-D",
"-", # "-D -" prints out HTML headers
"-L", # resolve 3xx redirects
url,
]
if not spack.config.get("config:verify_ssl"):
curl_args.append("-k")
if sys.stdout.isatty() and tty.msg_enabled():
curl_args.append("-#") # status bar when using a tty
else:
curl_args.append("-sS") # show errors if fail
connect_timeout = spack.config.get("config:connect_timeout", 10)
if timeout:
connect_timeout = max(int(connect_timeout), int(timeout))
if connect_timeout > 0:
curl_args.extend(["--connect-timeout", str(connect_timeout)])
return curl_args
[docs]
def check_curl_code(returncode):
"""Check standard return code failures for provided arguments.
Arguments:
returncode (int): curl return code
Raises FetchError if the curl returncode indicates failure
"""
if returncode != 0:
if returncode == 22:
# This is a 404. Curl will print the error.
raise spack.error.FetchError("URL was not found!")
if returncode == 60:
# This is a certificate error. Suggest spack -k
raise spack.error.FetchError(
"Curl was unable to fetch due to invalid certificate. "
"This is either an attack, or your cluster's SSL "
"configuration is bad. If you believe your SSL "
"configuration is bad, you can try running spack -k, "
"which will not check SSL certificates."
"Use this at your own risk."
)
raise spack.error.FetchError("Curl failed with error {0}".format(returncode))
def _curl(curl=None):
if not curl:
try:
curl = which("curl", required=True)
except CommandNotFoundError as exc:
tty.error(str(exc))
raise spack.error.FetchError("Missing required curl fetch method")
append_curl_env_for_ssl_certs(curl)
return curl
[docs]
def fetch_url_text(url, curl=None, dest_dir="."):
"""Retrieves text-only URL content using the configured fetch method.
It determines the fetch method from:
* config:url_fetch_method (str): fetch method to use (e.g., 'curl')
If the method is `curl`, it also uses the following configuration
options:
* config:connect_timeout (int): connection time out
* config:verify_ssl (str): Perform SSL verification
Arguments:
url (str): URL whose contents are to be fetched
curl (spack.util.executable.Executable or None): (optional) curl
executable if curl is the configured fetch method
dest_dir (str): (optional) destination directory for fetched text
file
Returns (str or None): path to the fetched file
Raises FetchError if the curl returncode indicates failure
"""
if not url:
raise spack.error.FetchError("A URL is required to fetch its text")
tty.debug("Fetching text at {0}".format(url))
filename = os.path.basename(url)
path = os.path.join(dest_dir, filename)
fetch_method = spack.config.get("config:url_fetch_method")
tty.debug("Using '{0}' to fetch {1} into {2}".format(fetch_method, url, path))
if fetch_method == "curl":
curl_exe = _curl(curl)
if not curl_exe:
raise spack.error.FetchError("Missing required fetch method (curl)")
curl_args = ["-O"]
curl_args.extend(base_curl_fetch_args(url))
# Curl automatically downloads file contents as filename
with working_dir(dest_dir, create=True):
_ = curl_exe(*curl_args, fail_on_error=False, output=os.devnull)
check_curl_code(curl_exe.returncode)
return path
else:
try:
_, _, response = read_from_url(url)
returncode = response.getcode()
if returncode and returncode != 200:
raise spack.error.FetchError(
"Urllib failed with error code {0}".format(returncode)
)
output = codecs.getreader("utf-8")(response).read()
if output:
with working_dir(dest_dir, create=True):
with open(filename, "w") as f:
f.write(output)
return path
except SpackWebError as err:
raise spack.error.FetchError("Urllib fetch failed to verify url: {0}".format(str(err)))
return None
[docs]
def url_exists(url, curl=None):
"""Determines whether url exists.
A scheme-specific process is used for Google Storage (`gs`) and Amazon
Simple Storage Service (`s3`) URLs; otherwise, the configured fetch
method defined by `config:url_fetch_method` is used.
Arguments:
url (str): URL whose existence is being checked
curl (spack.util.executable.Executable or None): (optional) curl
executable if curl is the configured fetch method
Returns (bool): True if it exists; False otherwise.
"""
tty.debug("Checking existence of {0}".format(url))
url_result = urllib.parse.urlparse(url)
# Use curl if configured to do so
use_curl = spack.config.get(
"config:url_fetch_method", "urllib"
) == "curl" and url_result.scheme not in ("gs", "s3")
if use_curl:
curl_exe = _curl(curl)
if not curl_exe:
return False
# Telling curl to fetch the first byte (-r 0-0) is supposed to be
# portable.
curl_args = ["--stderr", "-", "-s", "-f", "-r", "0-0", url]
if not spack.config.get("config:verify_ssl"):
curl_args.append("-k")
_ = curl_exe(*curl_args, fail_on_error=False, output=os.devnull)
return curl_exe.returncode == 0
# Otherwise use urllib.
try:
urlopen(
Request(url, method="HEAD", headers={"User-Agent": SPACK_USER_AGENT}),
timeout=spack.config.get("config:connect_timeout", 10),
)
return True
except URLError as e:
tty.debug("Failure reading URL: " + str(e))
return False
def _debug_print_delete_results(result):
if "Deleted" in result:
for d in result["Deleted"]:
tty.debug("Deleted {0}".format(d["Key"]))
if "Errors" in result:
for e in result["Errors"]:
tty.debug("Failed to delete {0} ({1})".format(e["Key"], e["Message"]))
[docs]
def remove_url(url, recursive=False):
url = urllib.parse.urlparse(url)
local_path = url_util.local_file_path(url)
if local_path:
if recursive:
shutil.rmtree(local_path)
else:
os.remove(local_path)
return
if url.scheme == "s3":
# Try to find a mirror for potential connection information
s3 = get_s3_session(url, method="push")
bucket = url.netloc
if recursive:
# Because list_objects_v2 can only return up to 1000 items
# at a time, we have to paginate to make sure we get it all
prefix = url.path.strip("/")
paginator = s3.get_paginator("list_objects_v2")
pages = paginator.paginate(Bucket=bucket, Prefix=prefix)
delete_request = {"Objects": []}
for item in pages.search("Contents"):
if not item:
continue
delete_request["Objects"].append({"Key": item["Key"]})
# Make sure we do not try to hit S3 with a list of more
# than 1000 items
if len(delete_request["Objects"]) >= 1000:
r = s3.delete_objects(Bucket=bucket, Delete=delete_request)
_debug_print_delete_results(r)
delete_request = {"Objects": []}
# Delete any items that remain
if len(delete_request["Objects"]):
r = s3.delete_objects(Bucket=bucket, Delete=delete_request)
_debug_print_delete_results(r)
else:
s3.delete_object(Bucket=bucket, Key=url.path.lstrip("/"))
return
elif url.scheme == "gs":
if recursive:
bucket = GCSBucket(url)
bucket.destroy(recursive=recursive)
else:
blob = GCSBlob(url)
blob.delete_blob()
return
# Don't even try for other URL schemes.
def _iter_s3_contents(contents, prefix):
for entry in contents:
key = entry["Key"]
if not key.startswith("/"):
key = "/" + key
key = os.path.relpath(key, prefix)
if key == ".":
continue
yield key
def _list_s3_objects(client, bucket, prefix, num_entries, start_after=None):
list_args = dict(Bucket=bucket, Prefix=prefix[1:], MaxKeys=num_entries)
if start_after is not None:
list_args["StartAfter"] = start_after
result = client.list_objects_v2(**list_args)
last_key = None
if result["IsTruncated"]:
last_key = result["Contents"][-1]["Key"]
iter = _iter_s3_contents(result["Contents"], prefix)
return iter, last_key
def _iter_s3_prefix(client, url, num_entries=1024):
key = None
bucket = url.netloc
prefix = re.sub(r"^/*", "/", url.path)
while True:
contents, key = _list_s3_objects(client, bucket, prefix, num_entries, start_after=key)
for x in contents:
yield x
if not key:
break
def _iter_local_prefix(path):
for root, _, files in os.walk(path):
for f in files:
yield os.path.relpath(os.path.join(root, f), path)
[docs]
def list_url(url, recursive=False):
url = urllib.parse.urlparse(url)
local_path = url_util.local_file_path(url)
if local_path:
if recursive:
# convert backslash to forward slash as required for URLs
return [str(PurePosixPath(Path(p))) for p in _iter_local_prefix(local_path)]
return [
subpath
for subpath in os.listdir(local_path)
if os.path.isfile(os.path.join(local_path, subpath))
]
if url.scheme == "s3":
s3 = get_s3_session(url, method="fetch")
if recursive:
return list(_iter_s3_prefix(s3, url))
return list(set(key.split("/", 1)[0] for key in _iter_s3_prefix(s3, url)))
elif url.scheme == "gs":
gcs = GCSBucket(url)
return gcs.get_all_blobs(recursive=recursive)
[docs]
def spider(
root_urls: Union[str, Iterable[str]], depth: int = 0, concurrency: Optional[int] = None
):
"""Get web pages from root URLs.
If depth is specified (e.g., depth=2), then this will also follow up to <depth> levels
of links from each root.
Args:
root_urls: root urls used as a starting point for spidering
depth: level of recursion into links
concurrency: number of simultaneous requests that can be sent
Returns:
A dict of pages visited (URL) mapped to their full text and the set of visited links.
"""
if isinstance(root_urls, str):
root_urls = [root_urls]
current_depth = 0
pages, links, spider_args = {}, set(), []
_visited: Set[str] = set()
go_deeper = current_depth < depth
for root_str in root_urls:
root = urllib.parse.urlparse(root_str)
spider_args.append((root, go_deeper, _visited))
with concurrent.futures.ProcessPoolExecutor(max_workers=concurrency) as tp:
while current_depth <= depth:
tty.debug(
f"SPIDER: [depth={current_depth}, max_depth={depth}, urls={len(spider_args)}]"
)
results = [tp.submit(_spider, *one_search_args) for one_search_args in spider_args]
spider_args = []
go_deeper = current_depth < depth
for future in results:
sub_pages, sub_links, sub_spider_args, sub_visited = future.result()
_visited.update(sub_visited)
sub_spider_args = [(x, go_deeper, _visited) for x in sub_spider_args]
pages.update(sub_pages)
links.update(sub_links)
spider_args.extend(sub_spider_args)
current_depth += 1
return pages, links
def _spider(url: urllib.parse.ParseResult, collect_nested: bool, _visited: Set[str]):
"""Fetches URL and any pages it links to.
Prints out a warning only if the root can't be fetched; it ignores errors with pages
that the root links to.
Args:
url: url being fetched and searched for links
collect_nested: whether we want to collect arguments for nested spidering on the
links found in this url
_visited: links already visited
Returns:
A tuple of:
- pages: dict of pages visited (URL) mapped to their full text.
- links: set of links encountered while visiting the pages.
- spider_args: argument for subsequent call to spider
- visited: updated set of visited urls
"""
pages: Dict[str, str] = {} # dict from page URL -> text content.
links: Set[str] = set() # set of all links seen on visited pages.
subcalls: List[str] = []
try:
response_url, _, response = read_from_url(url, "text/html")
if not response_url or not response:
return pages, links, subcalls, _visited
page = codecs.getreader("utf-8")(response).read()
pages[response_url] = page
# Parse out the include-fragments in the page
# https://github.github.io/include-fragment-element
metadata_parser = ExtractMetadataParser()
metadata_parser.feed(page)
# Change of base URL due to <base href="..." /> tag
response_url = metadata_parser.base_url or response_url
fragments = set()
while metadata_parser.fragments:
raw_link = metadata_parser.fragments.pop()
abs_link = url_util.join(response_url, raw_link.strip(), resolve_href=True)
fragment_response_url = None
try:
# This seems to be text/html, though text/fragment+html is also used
fragment_response_url, _, fragment_response = read_from_url(abs_link, "text/html")
except Exception as e:
msg = f"Error reading fragment: {(type(e), str(e))}:{traceback.format_exc()}"
tty.debug(msg)
if not fragment_response_url or not fragment_response:
continue
fragment = codecs.getreader("utf-8")(fragment_response).read()
fragments.add(fragment)
pages[fragment_response_url] = fragment
# Parse out the links in the page and all fragments
link_parser = LinkParser()
link_parser.feed(page)
for fragment in fragments:
link_parser.feed(fragment)
while link_parser.links:
raw_link = link_parser.links.pop()
abs_link = url_util.join(response_url, raw_link.strip(), resolve_href=True)
links.add(abs_link)
# Skip stuff that looks like an archive
if any(raw_link.endswith(s) for s in llnl.url.ALLOWED_ARCHIVE_TYPES):
continue
# Skip already-visited links
if abs_link in _visited:
continue
# If we're not at max depth, follow links.
if collect_nested:
subcalls.append(abs_link)
_visited.add(abs_link)
except URLError as e:
tty.debug(f"[SPIDER] Unable to read: {url}")
tty.debug(str(e), level=2)
if hasattr(e, "reason") and isinstance(e.reason, ssl.SSLError):
tty.warn(
"Spack was unable to fetch url list due to a "
"certificate verification problem. You can try "
"running spack -k, which will not check SSL "
"certificates. Use this at your own risk."
)
except HTMLParseError as e:
# This error indicates that Python's HTML parser sucks.
msg = "Got an error parsing HTML."
tty.warn(msg, url, "HTMLParseError: " + str(e))
except Exception as e:
# Other types of errors are completely ignored,
# except in debug mode
tty.debug(f"Error in _spider: {type(e)}:{str(e)}", traceback.format_exc())
finally:
tty.debug(f"SPIDER: [url={url}]")
return pages, links, subcalls, _visited
[docs]
def parse_etag(header_value):
"""Parse a strong etag from an ETag: <value> header value.
We don't allow for weakness indicators because it's unclear
what that means for cache invalidation."""
if header_value is None:
return None
# First follow rfc7232 section 2.3 mostly:
# ETag = entity-tag
# entity-tag = [ weak ] opaque-tag
# weak = %x57.2F ; "W/", case-sensitive
# opaque-tag = DQUOTE *etagc DQUOTE
# etagc = %x21 / %x23-7E / obs-text
# ; VCHAR except double quotes, plus obs-text
# obs-text = %x80-FF
# That means quotes are required.
valid = re.match(r'"([\x21\x23-\x7e\x80-\xFF]+)"$', header_value)
if valid:
return valid.group(1)
# However, not everybody adheres to the RFC (some servers send
# wrong etags, but also s3:// is simply a different standard).
# In that case, it's common that quotes are omitted, everything
# else stays the same.
valid = re.match(r"([\x21\x23-\x7e\x80-\xFF]+)$", header_value)
return valid.group(1) if valid else None
[docs]
class SpackWebError(spack.error.SpackError):
"""Superclass for Spack web spidering errors."""
[docs]
class NoNetworkConnectionError(SpackWebError):
"""Raised when an operation can't get an internet connection."""
def __init__(self, message, url):
super().__init__("No network connection: " + str(message), "URL was: " + str(url))
self.url = url