74 lines
3.0 KiB
Markdown
74 lines
3.0 KiB
Markdown
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<!--
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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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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-->
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# Docker images for building Hadoop
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This folder contains the Dockerfiles for building Hadoop on various platforms.
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# Dependency management
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The mode of installation of the dependencies needed for building Hadoop varies from one platform to
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the other. Different platforms have different toolchains. Some packages tend to be polymorphic
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across platforms and most commonly, a package that's readily available in one platform's toolchain
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isn't available on another. We thus, resort to building and installing the package from source,
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causing duplication of code since this needs to be done for all the Dockerfiles pertaining to all
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the platforms. We need a system to track a dependency - for a package - for a platform. Thus,
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there's a lot of diversity that needs to be handled for managing package dependencies and
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`pkg-resolver` caters to that.
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## Supported platforms
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`pkg-resolver/platforms.json` contains a list of the supported platforms for dependency management.
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## Package dependencies
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`pkg-resolver/packages.json` maps a dependency to a given platform. Here's the schema of this JSON.
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```json
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{
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"dependency_1": {
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"platform_1": "package_1",
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"platform_2": [
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"package_1",
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"package_2"
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]
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},
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"dependency_2": {
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"platform_1": [
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"package_1",
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"package_2",
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"package_3"
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]
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}
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}
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```
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The root JSON element contains unique _dependency_ children. This in turn contains the name of the _
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platforms_ and the list of _packages_ to be installed for that platform. Just to give an example of
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how to interpret the above JSON -
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1. For `dependency_1`, `package_1` needs to be installed for `platform_1`.
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2. For `dependency_2`, `package_1` and `package_2` needs to be installed for `platform_2`.
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3. For `dependency_2`, `package_1`, `package_3` and `package_3` needs to be installed for
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`platform_1`.
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## Standalone packages
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Most commonly, some packages are not available across the toolchains in various platforms. Thus, we
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would need to build and install them. Since we need to do this across all the Dockerfiles for all
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the platforms, it could lead to code duplication and managing them becomes a hassle. Thus, we put
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the build steps in a `pkg-resolver/install-<package>.sh` and invoke this in all the Dockerfiles.
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