193 lines
7.4 KiB
Python
193 lines
7.4 KiB
Python
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#!/usr/bin/env python3
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# Copyright 2019 The Kubernetes Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import json
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import re
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import requests
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import sys
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import tarfile
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from io import BytesIO
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KUBE_SRC = "https://dl.k8s.io"
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KUBE_RESOLVED_SEM = "kubernetes_semver"
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KUBE_RESOLVED_SRC = "kubernetes_http_source"
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KUBE_RESOLVED_VER = "kubernetes_version"
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# KubeVersionResolver is used for resolving Kubernetes version strings to the
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# actual version and URL or package string that may be used to deploy
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# Kubernetes.
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class KubeVersionResolver(object):
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# Resolve accepts a Kubernetes version string and returns a dictionary with
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# information that can be used to deploy the provided version.
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def Resolve(self, version):
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if version == '':
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raise Exception('version is required')
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result = {
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KUBE_RESOLVED_SEM: version,
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KUBE_RESOLVED_SRC: 'pkg',
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KUBE_RESOLVED_VER: version,
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}
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# When version is 'latest' then the returned dictionary points
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# to the latest package for Kubernetes.
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if version == 'latest':
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return result
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# Otherwise check to see if the provided version matches a
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# managed package format. Technically the else clause could be
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# descoped one level, but by placing the logic in the scope of
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# the else clause, the scope of 'match' is isolated from the
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# rest of this function.
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else:
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match = re.match(r'^(\d+\.\d+.\d+)\-\d+$', version)
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if match:
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version = match.groups(1)[0]
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result[KUBE_RESOLVED_SEM] = f'v{version}'
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return result
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url = ''
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if re.match(r'(?i)^https?:', version):
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url = version
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elif re.match(r'^v?\d+(?:\.\d+){0,3}(?:[.+-].+)?$', version):
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if not version.startswith('v'):
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version = f'v{version}'
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url = f'{KUBE_SRC}/release/{version}'
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elif re.match(r'^(ci|release)/.+$', version):
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url = self.__resolve_build_url(version)
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else:
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raise Exception(f'Invalid Kubernetes version: {version}')
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result[KUBE_RESOLVED_SRC] = url
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version = self.__read_version_from_kube_tarball(url)
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result[KUBE_RESOLVED_SEM] = version
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result[KUBE_RESOLVED_VER] = version
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return result
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def __resolve_build_url(self, buildID):
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url = f'{KUBE_SRC}/{buildID}'
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# If the URL doesn't end with '.txt' then see if the URL is already valid.
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if not url.endswith('.txt'):
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# If there is a kubernetes tarball available at the root of the URL
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# then it is already a valid URL.
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try:
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r = requests.head(url, allow_redirects=True)
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if r.status_code >= 200 and r.status_code <= 299:
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return url
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except:
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pass
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# The URL wasn't valid, so add '.txt' to the end and let's see if the
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# URL points to a valid build.
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url = f'{url}.txt'
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# Do an HTTP GET on the txt file to get the actual Kubernetes version.
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version = requests.get(url).text
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version = version.strip()
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if buildID.startswith('ci/'):
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version = f'ci/{version}'
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url = f'{KUBE_SRC}/{version}'
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return url
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def __read_version_from_kube_tarball(self, url):
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url = f'{url}/kubernetes.tar.gz'
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r = requests.get(url)
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if not r.status_code == 200:
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raise Exception(f'HTTP GET {url} failed: {r.status_code}')
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b = BytesIO(r.content)
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t = tarfile.open(fileobj=b, mode='r')
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v = t.extractfile('kubernetes/version')
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return v.read().strip().decode('utf-8')
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if __name__ == '__main__':
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import argparse
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import textwrap
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parser = argparse.ArgumentParser(
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formatter_class=argparse.RawTextHelpFormatter,
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description='Generates new Kubernetes image config',
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epilog=textwrap.dedent(r'''
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THE VERSION STRING
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====================================================================
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The version string not only determines what version of Kubernetes
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will be installed, but also *how* Kubernetes is installed.
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PLACEHOLDERS
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====================================================================
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The following placeholders are used in the examples below:
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BASE_URI https://dl.k8s.io
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K8S_TGZ kubernetes.tar.gz
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PACKAGE MANAGER INSTALLATION
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====================================================================
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If the version string matches the pattern "^\d+\.\d+.\d+\-\d+$",
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ex. 1.14.0-0, then Kubernetes is installed using the system's
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package manager, such as yum or apt.
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MANUAL INSTALLATION
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====================================================================
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If the string does not match the above pattern then the following
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logic is used to resolve the string VALUE to a valid Kubernetes
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version along with the URLs for the Kubernetes artifiacts required
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for installation:
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1. If the VALUE begins with "http:" or "https:" then the value is
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treated as a URL and the Kubernetes version is obtained by reading
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the "kuberentes/version" file from the URL "VALUE/K8S_TGZ".
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2. If the VALUE matches a semantic version then the value is
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treated as a release build and "BASE_URI/release/SEMVER"
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is processed like the URL in step one.
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3. If the VALUE begins with "ci/" then:
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a. If VALUE does not end with ".txt" then a HEAD request is used
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to check the existence of "BASE_URI/VALUE/K8S_TGZ":
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i. If the HEAD request is successful then the URL is processed
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like the one in step one.
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ii. If the HEAD request fails then ".txt" is added to the end
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of the URL and is processed by step 3b.
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b. If VALUE *does* end with ".txt" then a GET request is used to
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read "BASE_URI/VALUE" in order to get the dereferenced
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version string. Then "BASE_URI/ci/DEREF" is processed
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like the URL in step one.
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4. If the VALUE begins with "release/" then the VALUE is processed
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like step three, without the "ci/" prefix
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The resolved URL is used to install Kuberentes from the set of
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pre-built container images and binaries.
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'''))
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parser.add_argument('version',
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nargs=1,
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help='A Kubernetes version string')
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args = parser.parse_args()
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resolver = KubeVersionResolver()
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result = resolver.Resolve(args.version[0])
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data = json.dumps(result, indent=2)
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print(data)
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