Minor tweaks on and extract generate_file to common

Author: Francisco Rossi

bazel_ros2_rules/lib/extensions.bzl

@@ -39,6 +39,7 @@ def _local_ros2_implementation(module_ctx):
             "rosidl_default_generators",
             "service_msgs",
             "unique_identifier_msgs",
+            "xacro",  # required by the ros_xacro rule in xacro.bzl
         ]
 
     underlay = find_local_ros2_distribution(module_ctx)

bazel_ros2_rules/lib/private/common.bzl

@@ -35,6 +35,24 @@ def interfaces_filegroup(name, share_directory):
         ], allow_empty = True),
     )
 
+def _generate_file_impl(ctx):
+    out = ctx.actions.declare_file(ctx.label.name)
+    ctx.actions.write(out, ctx.attr.content, ctx.attr.is_executable)
+    return [DefaultInfo(
+        files = depset([out]),
+        data_runfiles = ctx.runfiles(files = [out]),
+    )]
+
+generate_file = rule(
+    attrs = {
+        "content": attr.string(mandatory = True),
+        "is_executable": attr.bool(default = False),
+    },
+    output_to_genfiles = True,
+    implementation = _generate_file_impl,
+)
+"""Writes a string to a file at build time."""
+
 def incorporate_rmw_implementation(kwargs, env_changes, rmw_implementation):
     target = REPOSITORY_ROOT + ":%s_cc" % rmw_implementation
     kwargs["data"] = kwargs.get("data", []) + [target]

bazel_ros2_rules/lib/private/ros_py.bzl

@@ -15,6 +15,7 @@ load(
 )
 load(
     ":common.bzl",
+    "generate_file",
     "incorporate_rmw_implementation",
 )
 load(
@@ -23,6 +24,8 @@ load(
     "RUNTIME_ENVIRONMENT",
 )
 
+_WORKSPACE_NAME = Label(REPOSITORY_ROOT + ":ros2").workspace_name
+
 def ros_import_binary(
         name,
         executable,
@@ -144,24 +147,7 @@ def _add_deps(existing, new):
             deps.append(dep)
     return deps
 
-def _generate_file_impl(ctx):
-    out = ctx.actions.declare_file(ctx.label.name)
-    ctx.actions.write(out, ctx.attr.content, ctx.attr.is_executable)
-    return [DefaultInfo(
-        files = depset([out]),
-        data_runfiles = ctx.runfiles(files = [out]),
-    )]
-
-_generate_file = rule(
-    attrs = {
-        "content": attr.string(mandatory = True),
-        "is_executable": attr.bool(default = False),
-    },
-    output_to_genfiles = True,
-    implementation = _generate_file_impl,
-)
-
-_LAUNCH_PY_TEMPLATE = """
+_LAUNCH_PY_TEMPLATE = """\
 import os
 import sys
 
@@ -170,7 +156,7 @@ from python.runfiles import runfiles as runfiles_api
 assert __name__ == "__main__"
 runfiles = runfiles_api.Create()
 launch_file = runfiles.Rlocation({launch_respath})  # noqa
-ros2_bin = runfiles.Rlocation("ros2/ros2")
+ros2_bin = runfiles.Rlocation("{ros2_rlocation}")
 args = [ros2_bin, "launch", launch_file] + sys.argv[1:]
 os.execv(ros2_bin, args)
 """
@@ -215,8 +201,9 @@ def ros_launch(
 
     content = _LAUNCH_PY_TEMPLATE.format(
         launch_respath = repr(launch_respath),
+        ros2_rlocation = _WORKSPACE_NAME + "/ros2",
     )
-    _generate_file(
+    generate_file(
         name = main,
         content = content,
         visibility = ["//visibility:private"],

bazel_ros2_rules/lib/private/xacro.bzl

@@ -2,6 +2,7 @@
 """
 
 load("@bazel_ros2_rules//lib:ament_index.bzl", "ament_index_share_files")
+load(":common.bzl", "generate_file")
 load(":distro.bzl", "REPOSITORY_ROOT")
 load(":ros_py.bzl", "ros_py_binary")
 
@@ -10,20 +11,6 @@ load(":ros_py.bzl", "ros_py_binary")
 # formats correctly without manual string manipulation.
 _WORKSPACE_NAME = Label(REPOSITORY_ROOT + ":xacro").workspace_name
 
-def _xacro_generate_file_impl(ctx):
-    out = ctx.actions.declare_file(ctx.label.name)
-    ctx.actions.write(out, ctx.attr.content, is_executable = True)
-    return [DefaultInfo(
-        files = depset([out]),
-        data_runfiles = ctx.runfiles(files = [out]),
-    )]
-
-_xacro_generate_file = rule(
-    attrs = {"content": attr.string(mandatory = True)},
-    output_to_genfiles = True,
-    implementation = _xacro_generate_file_impl,
-)
-
 # Runner script template.  The outer dload shim (from ros_py_binary) has
 # already set AMENT_PREFIX_PATH to include both system and user-package
 # prefixes (all absolute via $RUNFILES_DIR) before this script runs.  What is
@@ -41,7 +28,7 @@ os.execv(xacro_bin, [xacro_bin] + sys.argv[1:])
 """
 
 def _ros_xacro_impl(ctx):
-    output = ctx.actions.declare_file(ctx.attr.name + ".urdf")
+    output = ctx.actions.declare_file(ctx.label.name + ".urdf")
     args = ctx.actions.args()
     args.add(ctx.file.src)
     args.add("-o", output)
@@ -62,9 +49,9 @@ _ros_xacro_rule = rule(
             doc = "The main .urdf.xacro file to process.",
         ),
         "data": attr.label_list(
-            allow_files = [".xacro"],
+            allow_files = True,
             default = [],
-            doc = "Additional .xacro files included via relative paths.",
+            doc = "Additional files included via relative paths (e.g. .xacro, .yaml).",
         ),
         "xacro_args": attr.string_list(
             default = [],
@@ -80,7 +67,7 @@ _ros_xacro_rule = rule(
     implementation = _ros_xacro_impl,
 )
 
-def ros_xacro(name, src, data = [], ros_packages = {}, xacro_args = [], visibility = None, **kwargs):
+def ros_xacro(name, src, data = [], ros_packages = {}, xacro_args = [], visibility = None):
     """Transforms a .urdf.xacro file into a .urdf file.
 
     User-defined packages are declared inline via the ros_packages dict.  Each
@@ -107,10 +94,11 @@ def ros_xacro(name, src, data = [], ros_packages = {}, xacro_args = [], visibili
     Args:
         name:         target name; the output file is named <name>.urdf
         src:          the .urdf.xacro source file
-        data:         additional .xacro files included via relative paths
-                      (i.e. plain <xacro:include filename="other.xacro"/>);
-                      must be listed here so Bazel sandboxes them and tracks
-                      them as dependencies for incremental rebuilds
+        data:         additional files included via relative paths
+                      (e.g. plain <xacro:include filename="other.xacro"/>
+                      or referenced .yaml configs); must be listed here so
+                      Bazel sandboxes them and tracks them as dependencies
+                      for incremental rebuilds
         ros_packages: dict mapping ROS package name to list of share files;
                       files are stripped of the calling package's path prefix
                       automatically before being placed under share/<pkg>/
@@ -133,7 +121,7 @@ def ros_xacro(name, src, data = [], ros_packages = {}, xacro_args = [], visibili
     runner_data = [REPOSITORY_ROOT + ":xacro"] + pkg_targets
 
     runner_main = "_{}_runner_main.py".format(name)
-    _xacro_generate_file(
+    generate_file(
         name = runner_main,
         content = _XACRO_RUNNER_TEMPLATE.format(
             xacro_rlocation = _WORKSPACE_NAME + "/xacro",

ros2_example_bazel_installed/ros2_example_xacro/example.urdf.xacro

@@ -6,8 +6,13 @@
   <xacro:include filename="$(find my_robot)/urdf/macros.xacro"/>
   <!-- Should be able to bring `.xacros` installed in the system (via `realsense2_description` for this example)-->
   <xacro:include filename="$(find realsense2_description)/urdf/_d435i.urdf.xacro"/>
-   <!-- Should be able to retrieve xacro args-->
-   <xacro:arg name="sim" default="true" />
-   <xacro:property name="sim_mode" value="$(arg sim)"/>
-   <sim>${sim_mode}</sim>
+  <!-- Should be able to retrieve xacro args-->
+  <xacro:arg name="sim" default="true" />
+  <xacro:property name="sim_mode" value="$(arg sim)"/>
+  <sim>${sim_mode}</sim>
+  <!-- Instantiate the D435i sensor to verify $(find realsense2_description) actually resolved. -->
+  <link name="base_link"/>
+  <xacro:sensor_d435i parent="base_link" name="head_camera" use_nominal_extrinsics="true">
+    <origin xyz="0 0 0" rpy="0 0 0"/>
+  </xacro:sensor_d435i>
 </robot>

ros2_example_bazel_installed/ros2_example_xacro/test/xacro_test.py

@@ -38,8 +38,25 @@ def test_relative_include_expanded():
     )
 
 
+def test_system_package_include_resolved():
+    """$(find realsense2_description) is resolved and its macros are expanded.
+
+    Verifies that ros_xacro sets AMENT_PREFIX_PATH so xacro can find
+    system-installed ROS packages. The D435i macro from
+    realsense2_description is instantiated in the example xacro; if the
+    include had not resolved, xacro would have exited non-zero and the
+    output URDF would not exist.
+    """
+    content = _read_urdf()
+    assert 'name="head_camera_link"' in content, (
+        "Expected D435i links from realsense2_description in output:\n"
+        + content
+    )
+
+
 if __name__ == "__main__":
     test_sim_arg_is_substituted()
     test_local_package_macros_expanded()
     test_relative_include_expanded()
+    test_system_package_include_resolved()
     print("All tests passed.")