src/main/java/com/google/devtools/build/lib/bazel/rules/workspace/MavenJarRule.java

// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.devtools.build.lib.bazel.rules.workspace;

import static com.google.devtools.build.lib.packages.Attribute.attr;

import com.google.devtools.build.lib.analysis.RuleDefinition;
import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
import com.google.devtools.build.lib.packages.RuleClass;
import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
import com.google.devtools.build.lib.rules.repository.WorkspaceBaseRule;
import com.google.devtools.build.lib.rules.repository.WorkspaceConfiguredTargetFactory;
import com.google.devtools.build.lib.syntax.Type;

/**
 * Rule definition for the maven_jar rule.
 */
public class MavenJarRule implements RuleDefinition {

  public static final String NAME = "maven_jar";

  @Override
  public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment environment) {
    return builder
        /* <!-- #BLAZE_RULE(maven_jar).ATTRIBUTE(artifact) -->
        A description of a Maven artifact using
        <a href="https://maven.apache.org/pom.html#Maven_Coordinates">Maven coordinates</a>.

        <p>These descriptions are of the form &lt;groupId&gt:&lt;artifactId&gt;:&lt;version&gt;,
        see <a href="${link maven_jar_examples}">the documentation below</a> for an example.
        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
        .add(attr("artifact", Type.STRING))
        /* <!-- #BLAZE_RULE(maven_jar).ATTRIBUTE(repository) -->
        A URL for a Maven repository to fetch the jar from.

        <p>Either this or <code>server</code> can be specified. Defaults to Maven Central
         ("central.maven.org").</p>
        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
        .add(attr("repository", Type.STRING))
        /* <!-- #BLAZE_RULE(maven_jar).ATTRIBUTE(server) -->
        A maven_server to use for this artifact.

        <p>Either this or <code>repository</code> can be specified.</p>
        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
        .add(attr("server", Type.STRING))
        /* <!-- #BLAZE_RULE(maven_jar).ATTRIBUTE(sha1) -->
        A SHA-1 hash of the desired jar.

        <p>If the downloaded jar does not match this hash, Bazel will error out. It is a security
        risk to download a file without verifying cryptographic secure hash. <b>Note that SHA-1 is
        no longer considered a secure cryptographic hash function</b>, but specifying the hash is
        still marginally better than no check at all. This attribute is kept here for legacy support
        purposes. Please migrate to <a href="https://github.com/bazelbuild/rules_jvm_external/">
        <code>rules_jvm_external</code></a> and pin your Maven artifacts with their SHA-256
        checksums.</p>
        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
        .add(attr("sha1", Type.STRING))
        /* <!-- #BLAZE_RULE(maven_jar).ATTRIBUTE(sha1_src) -->
        A SHA-1 hash of the desired jar source file.

        <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
        .add(attr("sha1_src", Type.STRING))
        .setWorkspaceOnly()
        .build();
  }

  @Override
  public Metadata getMetadata() {
    return RuleDefinition.Metadata.builder()
        .name(MavenJarRule.NAME)
        .type(RuleClassType.WORKSPACE)
        .ancestors(WorkspaceBaseRule.class)
        .factoryClass(WorkspaceConfiguredTargetFactory.class)
        .build();
  }
}
/*<!-- #BLAZE_RULE (NAME = maven_jar, TYPE = OTHER, FAMILY = Workspace)[GENERIC_RULE] -->

<p>Downloads a jar from Maven and makes it available to be used as a Java dependency.</p>

<h4 id="maven_jar_name">Naming</h4>

<p>Note that the maven_jar name is used as a repository name, so it is limited by the rules
governing workspace names: it cannot contain dashes nor dots (see
<a href="http://bazel.build/docs/be/functions.html#workspace">the documentation on workspace
names</a> for the exact specification). By convention, maven_jar names should match the artifact
name, replacing illegal characters with underscores and leaving off the version.  For example, a
rule with <code>artifact = "org.apache.commons:commons-lang3:3.4"</code> should have
<code>name = "org_apache_commons_commons_lang3"</code>.</p>

<h4 id="maven_jar_examples">Examples</h4>

Suppose that the current repostory contains a java_library target that needs to depend on Guava.
Using Maven, this dependency would be defined in the pom.xml file as:

<pre>
&lt;dependency>
    &lt;groupId>com.google.guava&lt;/groupId>
    &lt;artifactId>guava&lt;/artifactId>
    &lt;version>18.0&lt;/version>
&lt;/dependency>
</pre>

With Bazel, add the following lines to the WORKSPACE file:

<pre>
maven_jar(
    name = "com_google_guava_guava",
    artifact = "com.google.guava:guava:18.0",
    sha1 = "cce0823396aa693798f8882e64213b1772032b09",
    sha1_src = "ad97fe8faaf01a3d3faacecd58e8fa6e78a973ca",
)
</pre>

<p>Targets can specify <code>@com_google_guava_guava//jar</code> as a dependency to depend on this
jar.</p>

<!-- #END_BLAZE_RULE -->*/