{namespace genrule}

/***/
{template .soyweb}
  {call buck.page}
    {param title: 'genrule()' /}
    {param prettify: true /}
    {param content}

{call buck.rule}
{param overview}
  A <code>genrule()</code> is used to generate a file from a shell
  command. It must produce a single output file.
{/param}

{param args}

{call buck.arg}
  {param name: 'name' /}
  {param desc}
  The name of the genrule.
  {/param}
{/call}

{call buck.arg}
  {param name: 'srcs' /}
  {param desc}
  A list of files to be used in the shell command.
  {/param}
{/call}

{call buck.arg}
  {param name: 'cmd' /}
  {param desc}
  The shell command to run to generate the output file. It will be
  subject to the following environment variable substitutions:
    <dl>
      <dt><code>SRCS</code><dt>
      <dd>A space-delimited string expansion of the <code>srcs</code>
      {sp}argument where each element of <code>srcs</code> will be
      translated into an absolute path.</dd>

      <dt><code>OUT</code></dt>
      <dd>The output file for the <code>genrule()</code>. The file
      specified by this variable must always be written by this
      command. If not, the execution of this rule will be considered a
      failure, halting the build process.</dd>
    </dl>

    Also, references to binary build rules (such as
    {sp}<code>java_binary()</code> or <code>python_binary()</code>) may be
    inserted, as well. For example, if
    {sp}<code>//java/src/com/example:main</code> referred to a
    {sp}<code>java_binary()</code> rule, then <code>cmd</code> could be
    {sp}'<code>${lb}//java/src/com/example:main{rb} arg1 arg2
    arg3</code>', provided that <code>:main</code> were listed in the
    {sp}<code>deps</code> of the <code>genrule()</code>.
  {/param}
{/call}

{call buck.arg}
  {param name: 'out' /}
  {param desc}
   The name of the output file. Must be unique within the build file
   in which the <code>genrule()</code> is declared.
  {/param}
{/call}

{call buck.arg}
  {param name: 'deps' /}
  {param desc}
  A list of rules that must be built before this rule. These may be
  accessed within the command by treating the target as a
  brace-wrapped variable (<code>${lb}//like:this{rb}</code>).
  {/param}
{/call}

{call buck.visibility_arg /}

{/param} // args

{param examples}

This genrule() uses a Python script to derive a new
{sp}<code>AndroidManifest.xml</code> from an
{sp}<code>AndroidManifest.xml</code> in the source tree.

{literal}<pre class="prettyprint lang-py">
genrule(
  name = 'generate_manifest',
  srcs = [
    'basic_to_full_manifest.py',
    'AndroidManifest.xml',
  ],
  cmd = 'python $SRC_0 $SRC_1 > $OUT',
  out = 'AndroidManifest.xml',
)
</pre>{/literal}

<h2>See Also</h2>

<a href="{ROOT}function/genfile.html"><code>genfile()</code></a>
{sp}function.

{/param} // examples

{/call} // buck.rule

 {/param}
  {/call}
{/template}