path: root/src/main/java/com/google/devtools/build/docgen/templates/be-footer.html

<!-- =================================================================
                              package()
     =================================================================
-->

<h3 id="package">package</h3>

<p><code>package(default_deprecation,

  default_obsolete,
  default_testonly,
  default_visibility,
  features)</code>
</p>

<p>This function declares metadata that applies to every subsequent rule in the
package. It is used at most once within a package (BUILD file).</p>

<p>It is recommended that the package function is called at the top of the
file, before any rule.</p>

<h4 id="package_args">Arguments</h4>

<ul>
  <li id="package.default_visibility"><code>default_visibility</code>:
    The default visibility of the rules in this package.
    <i>(List of <a href="build-ref.html#labels">labels</a>; optional)</i><br/>

    <p>Every rule in this package has the visibility specified in this
    attribute, unless otherwise specified in the <code>visibility</code>
    attribute of the rule. For detailed information about the syntax of this
    attribute, see the documentation of the <a href="#common.visibility">visibility</a>
    attribute. The package default visibility applies neither to the
    <a href="#exports_files">exports_files</a> function nor to the
    <a href="#cc_public_library">cc_public_library</a> rule (which are
    public by default).
  </li>

  <li id="package.default_obsolete"><code>default_obsolete</code>:
    The default value of <a href="#common.obsolete"><code>obsolete</code></a> property
    for all rules in this package. <i>(Boolean; optional; default is 0)</i>
  </li>

  <li id="package.default_deprecation"><code>default_deprecation</code>:
    Sets the default <a href="#common.deprecation"><code>deprecation</code></a> message
    for all rules in this package. <i>(String; optional)</i>
  </li>

  <li id="package.default_testonly"><code>default_testonly</code>:
    Sets the default <a href="#common.testonly"><code>testonly</code></a> property
    for all rules in this package. <i>(Boolean; optional; default is 0 except as noted)</i>

    <p>In packages under <code>javatests</code> the default value is 1.</p>
  </li>

  <li id="package.features"><code>features</code>:
    Sets various flags that affect the semantics of this BUILD file.
    <i>(List strings; optional)</i>

    <p>This feature is mainly used by the people working on the build system to
    tag packages that need some kind of special handling. Do not use this unless
    explicitly requested by someone working on the build system.</p>
  </li>

</ul>

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

The declaration below declares that the rules in this package are
visible only to members of package
group <code>//foo:target</code>. Individual visibility declarations
on a rule, if present, override this specification.

<pre class="code">
package(default_visibility = ["//foo:target"])
</pre>

<!-- =================================================================
                              package_group()
     =================================================================
-->

<h3 id="package_group">package_group</h3>

<p><code>package_group(name, packages, includes)</code></p>

<p>This function defines a set of packages and assigns a label to the
group. The label can be referenced in <code>visibility</code> attributes.</p>

<p>Package groups are used for visibility control.  You can grant access to a rule
to one or more package groups, every rule in the entire source tree, or only to rules declared
in the same package. For more detailed description of the visibility system, see
the <a href="#common.visibility">visibility</a> attribute.

<h4 id="package_group_args">Arguments</h4>

<ul>
  <li id="package_group.name"><code>name</code>:
    A unique name for this rule.
    <i>(<a href="build-ref.html#name">Name</a>; required)</i>
  </li>

  <li id="package_group.packages"><code>packages</code>:
    A complete enumeration of packages in this group.
    <i>(List of <a href="build-ref.html#s4">Package</a>; optional)</i><br/>

    <p>Packages should be referred to using their full names,
    starting with a double slash. For
    example, <code>//foo/bar/main</code> is a valid element
    of this list.</p>

    <p>You can also specify wildcards: the specification
    <code>//foo/...</code> specifies every package under
    <code>//foo</code>, including <code>//foo</code> itself.

    <p>If this attribute is missing, the package group itself will contain
    no packages (but it can still include other package groups).</p>
  </li>

  <li id="package_group.includes"><code>includes</code>:
    Other package groups that are included in this one.
    <i>(List of <a href="build-ref.html#labels">labels</a>; optional)</i><br/>

    <p>The labels in this attribute must refer to other package
    groups. Packages in referenced package groups are taken to be part
    of this package group. This is transitive, that is, if package
    group <code>a</code> contains package group <code>b</code>,
    and <code>b</code> contains package group <code>c</code>, every
    package in <code>c</code> will also be a member of <code>a</code>.</p>
  </li>
</ul>


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

The following <code>package_group</code> declaration specifies a
package group called "tropical" that contains tropical fruits.

<pre class="code">
package_group(
    name = "tropical",
    packages = [
        "//fruits/mango",
        "//fruits/orange",
        "//fruits/papaya/...",
    ],
)
</pre>

The following declarations specify the package groups of a fictional
application:

<pre class="code">
package_group(
    name = "fooapp",
    includes = [
        ":controller",
        ":model",
        ":view",
    ],
)

package_group(
    name = "model",
    packages = ["//fooapp/database"],
)

package_group(
    name = "view",
    packages = [
        "//fooapp/swingui",
        "//fooapp/webui",
    ],
)

package_group(
    name = "controller",
    packages = ["//fooapp/algorithm"],
)
</pre>


<!-- =================================================================
                        exports_files([label, ...])
     =================================================================
  -->

<h3 id="exports_files">exports_files</h3>

<p><code>exports_files([<i>label</i>, ...], visibility, licenses)</code></p>

<p>
  <code>exports_files()</code> specifies a list of files belonging to
  this package that are exported to other packages but not otherwise
  mentioned in the BUILD file.
</p>

<p>
  The BUILD file for a package may only refer to files belonging to another
  package if they are mentioned somewhere in the other packages's BUILD file,
  whether as an input to a rule or an explicit or implicit output from a rule.
  The remaining files are not associated with a specific rule but are just "data",
  and for these, <code>exports_files</code> ensures that they may be referenced by
  other packages.  (One kind of data for which this is particularly useful are
  shell scripts.)
</p>

<p>
  Note: A BUILD file only consisting of <code>exports_files()</code> statements
  is needless though, as there are no BUILD rules that could own any files.
  The files listed can already be accessed through the containing package and
  exported from there if needed.
</p>

<h4 id="exports_files_args">Arguments</h4>

<p>
  The argument is a list of names of files within the current package. A
  visibility declaration can also be specified; in this case, the files will be
  visible to the targets specified. If no visibility is specified, the files
  will be visible to every package, even if a package default visibility was
  specified in the <code><a href="#package">package</a></code> function. The
  <a href="#common.licenses">licenses</a> can also be specified.
</p>

<h4 id="exports_files_example">Example</h4>

<p>
  The following example exports <code>golden.txt</code>, a
  text file from the <code>test_data</code> package, so that other
  packages may use it, for example, in the <code>data</code> attribute
  of tests.
</p>

<pre class="code">
# from //test_data/BUILD

exports_files(["golden.txt"])
</pre>

<!-- =================================================================
                               glob()
     =================================================================
  -->

<h3 id="glob">glob</h3>

<p><code>glob(include, exclude=[], exclude_directories=1)</code>
</p>

<p>
Glob is a helper function that can be used anywhere a list of filenames
is expected.  It takes one or two lists of filename patterns containing
the <code>*</code> wildcard: as per the Unix shell, this wildcard
matches any string excluding the directory separator <code>/</code>.
In addition filename patterns can contain the recursive <code>**</code>
wildcard. This wildcard will match zero or more complete
path segments separated by the directory separator <code>/</code>.
This wildcard can only be used as a complete path segment. For example,
<code>"x/**/*.java"</code> is legal, but <code>"test**/testdata.xml"</code>
and <code>"**.java"</code> are both illegal. No other wildcards are supported.
</p>
<p>
Glob returns a list of every file in the current package that:
</p>
<ul>
  <li>Matches at least one pattern in <code>include</code>. </li>
  <li>Does not match any of the patterns in <code>exclude</code> (default []).</li>
</ul>
<p>
If the <code>exclude_directories</code> argument is enabled (set to 1), files of
type directory will be omitted from the results (default 1).
</p>
<p>
There are several important limitations and caveats:
</p>

<ol>
  <li>
    Globs only match files in your source tree, never
    generated files.  If you are building a target that requires both
    source and generated files, create an explicit list of generated
    files, and use <code>+</code> to add it to the result of the
    <code>glob()</code> call.
  </li>

  <li>
    Globs may match files in subdirectories.  And subdirectory names
    may be wildcarded.  However...
  </li>

  <li>
    Labels are not allowed to cross the package boundary and glob does
    not match files in subpackages.

    For example, the glob expression <code>**/*.cc</code> in package
    <code>x</code> does not include <code>x/y/z.cc</code> if
    <code>x/y</code> exists as a package (either as
    <code>x/y/BUILD</code>, or somewhere else on the package-path). This
    means that the result of the glob expression actually depends on the
    existence of BUILD files &mdash; that is, the same glob expression would
    include <code>x/y/z.cc</code> if there was no package called
    <code>x/y</code> or it was marked as deleted using the
    <a href="bazel-user-manual.html#flag--deleted_packages">--deleted_packages</a>
    flag.

  </li>

  <li>
    The restriction above applies to all glob expressions,
    no matter which wildcards they use.
  </li>
  <li>
    A hidden file with filename starting with <code>.</code> is matched by
    both the <code>**</code> and the <code>*</code> wildcards.
  </li>
  <li>
    If a rule and a source file with the same name both exist in the package, the glob will
    return the outputs of the rule instead of the source file.
  </li>
</ol>

<p>
In general, you should <b>try to provide an appropriate extension (e.g. *.html)
instead of using a bare '*'</b> for a glob pattern. The more explicit name
is both self documenting and ensures that you don't accidentally match backup
files, or emacs/vi/... auto-save files.
</p>

<p>
When writing build rules you can enumerate the elements of the glob. This
enables generating individual rules for every input, for example. See the
<a href="#expanded_glob_example">expanded glob example</a> section below.
</p>

<h4 id="glob_example">Glob Examples</h4>

<p> Create a Java library built from all java files in this directory,
and all files generated by the <code>:gen_java_srcs</code> rule.</p>
<pre class="code">
java_library(
    name = "mylib",
    srcs = glob(["*.java"]) + [":localize_strings"],
    deps = "...",
)

genrule(
    name = "gen_java_srcs",
    outs = [
        "Foo.java",
        "Bar.java",
    ],
    ...
)
</pre>

<p>Include all txt files in directory testdata except experimental.txt.
Note that files in subdirectories of testdata will not be included. If
you want those files to be included, use a recursive glob (**).</p>
<pre class="code">
sh_test(
    name = "mytest",
    srcs = ["mytest.sh"],
    data = glob(
        ["testdata/*.txt"],
        exclude = ["testdata/experimental.txt"],
    ),
)
</pre>

<h4 id="recursive_glob_example">Recursive Glob Examples</h4>

<p>Create a library built from all java files in this directory and all
subdirectories except those whose path includes a directory named testing.
Subdirectories containing a BUILD file are ignored.
<b>This should be a very common pattern.</b>
</p>
<pre class="code">
java_library(
    name = "mylib",
    srcs = glob(
        ["**/*.java"],
        exclude = ["**/testing/**"],
    ),
)
</pre>

<p>Make the test depend on all txt files in the testdata directory,
   its subdirectories</p>
<pre class="code">
sh_test(
    name = "mytest",
    srcs = ["mytest.sh"],
    data = glob(["testdata/**/*.txt"]),
)
</pre>

<h4 id="expanded_glob_example">Expanded Glob Examples</h4>

<p>
Create an individual genrule for *_test.cc in the current directory
that counts the number of lines in the file.
</p>

<pre class="code">
# Conveniently, the build language supports list comprehensions.
[genrule(
    name = "count_lines_" + f[:-3],  # strip ".cc"
    srcs = [f],
    outs = ["%s-linecount.txt" % f[:-3]],
    cmd = "wc -l $&lt; &gt;$@",
 ) for f in glob(["*_test.cc"])]
</pre>

<p>
If the BUILD file above is in package //foo and the package contains three
matching files, a_test.cc, b_test.cc and c_test.cc then running
<code>bazel query '//foo:all'</code> will list all rules that were generated:

<pre>
$ bazel query '//foo:all' | sort
//foo:count_lines_a_test
//foo:count_lines_b_test
//foo:count_lines_c_test
</pre>


<!-- =================================================================
                              licenses()
     =================================================================
-->

<h3 id="licenses">licenses</h3>

<p><code>licenses(license_types)</code></p>

<p><code>licenses()</code> specifies the default license type (or types)
   of the build rules in a <code>BUILD</code> file.

   The <code>licenses()</code> directive should appear close to the
   beginning of the <code>BUILD</code> file, before any build rules, as it
   sets the <code>BUILD</code>-file scope default for build rule license
   types.</p>

<h4 id="licenses_args">Arguments</h4>

<p>The argument, <code id="licenses.licence_types">license_types</code>,
   is a list of license-type strings.
   <!-- TODO(bazel-team): specify some examples -->

</p>

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

<p>The following example specifies a single license type of
  <code>"notice"</code>.  Third-party software licenses that do not require
  publishing of source code changes but require some sort of copyright or
  other public notice are included in this license type.
</p>

<pre class="code">

licenses(["notice"])  # MIT license

exports_files(["jquery-2.1.1.js"])
</pre>

<!-- =================================================================
                              load()
     =================================================================
-->

<h3 id="load">load</h3>

<p><code>load(path, symbols...)</code></p>

<p><code>load()</code> is a statement that imports definitions from a
  Skylark module. For example:
</p>

<pre class="code">
load("/tools/build_rules/build_test", "build_test")

build_test(name = ...)
</pre>

<p>This will execute the

  Skylark
  module <code>tools/build_rules/build_test.bzl</code> and import the symbol
  <code>build_test</code> in the local environment. By using more arguments, you
  can load more symbols at once.</p>


<!-- =================================================================
                              select()
     =================================================================
-->

<h3 id="select">select</h3>

<p><code>select({conditionA: valuesA, conditionB: valuesB, ...})</code>
</p>

<p><code>select()</code> is the helper function that makes an
  attribute for a
  rule <a href="#configurable-attributes">configurable</a>. It can
  replace the right-hand side of

  <i>almost</i>
  any attribute assignment so that the attribute's value depends on the
  Bazel flags passed in at the command line. This can be used, for
  example, to define platform-specific dependencies or to embed
  different resources depending on whether a rule is built in
  "developer" vs. "release" mode.
</p>

<p>Basic usage is as follows:</p>

<pre class="code">
sh_binary(
    name = "myrule",
    srcs = select({
        ":conditionA": ["myrule_a.sh"],
        ":conditionB": ["myrule_b.sh"],
        "//conditions:default": ["myrule_default.sh"]
    })
)
</pre>

<p>This makes the <code>srcs</code> attribute of
  a <code>sh_binary</code> configurable by replacing its normal label
  list assignment with a <code>select</code> call that maps
  configuration conditions to matching values. Each condition is a label
  reference to
  a <code><a href="#config_setting">config_setting</a></code> instance,
  which "matches" if the rule's configuration matches an expected set of
  values. The value of <code>myrule#srcs</code> then becomes whichever
  label list matches the current invocation.
</p>

<p>Further notes:</p>

<ul>
  <li>Exactly one condition is selected on any invocation.
  </li>
  <li>If two conditions match and one is a specialization of the other
    (e.g. it matches on the same flags as the other plus additional flags),
    the specialization takes precedence.
  </li>
  <li>If two conditions match and neither is a specialization of the other,
    Bazel fails with an error.
  </li>
  <li>The special pseudo-label <code>//conditions:default</code> is
    considered to match if no other condition matches. If this condition
    is left out, some other rule must match to avoid an error.
  </li>
  <li><code>select</code> cannot currently be embedded <i>within</i> an
    attribute assignment. In other words, <code>srcs = ["common.sh"]
    + select({ "conditionA": ["myrule_a.sh"], ...})</code> does not
    currently work.
  </li>
  <li><code>select</code> works with most, but not all, attributes.

  </li>
</ul>

<!-- =================================================================
                              workspace()
     =================================================================
-->

<h3 id="workspace">workspace</h3>

<p><code>workspace(name = "something")</code></p>

<p>This can only be used in the WORKSPACE file.</p>

<p>The sets an optional name for the repository.</p>

<p>This name is used for the directory that runfiles are stored in. For
  example, if there is a runfile foo/bar and the WORKSPACE file contains
  <code>workspace(name = "baz")</code>, then the runfile will be output under
  mytarget.runfiles/baz/foo/bar.  If no workspace name is specified, then the
  runfile will be symlinked to bar.runfiles/foo/bar.
</p>

<p>A workspace name can contain slashes if a deeper directory listing is
  desired (<code>workspace(name = "baz/qux")</code> will place the runfile at
  bar.runfiles/baz/qux/foo/bar).
</p>

</div>
</div>
</body>
</html>