Add capability to use ros2 param set for array types

[sgvandijk]

Using YAML parsing to determine the value parameter type, the supported parameter types are extended to array types. Only the byte array type is excluded, I don't see a way of expressing that in YAML in an unambiguous way.

Fixes #198

[dirk-thomas]

Please install the additional flake8 plugins mentioned in the instructions and address the resulting linter warnings:

./test/test_api.py:16:1: I100 Import statements are in the wrong order. 'from rcl_interfaces.msg import ParameterType' should be before 'from ros2param.api import get_parameter_value'
from rcl_interfaces.msg import ParameterType
^

./test/test_api.py:62:46: Q000 Remove bad quotes
    value = get_parameter_value(string_value="foo")
                                             ^

./test/test_api.py:64:34: Q000 Remove bad quotes
    assert value.string_value == "foo"
                                 ^

./test/test_api.py:88:41: Q000 Remove bad quotes
    assert value.string_array_value == ["foo", "bar", "buzz"]
                                        ^

./test/test_api.py:88:48: Q000 Remove bad quotes
    assert value.string_array_value == ["foo", "bar", "buzz"]
                                               ^

./test/test_api.py:88:55: Q000 Remove bad quotes
    assert value.string_array_value == ["foo", "bar", "buzz"]
                                                      ^

./ros2param/api/__init__.py:43:12: C407 Unnecessary list comprehension - 'all' can take a generator.
        if all([isinstance(v, bool) for v in yaml_value]):
           ^

./ros2param/api/__init__.py:46:14: C407 Unnecessary list comprehension - 'all' can take a generator.
        elif all([isinstance(v, int) for v in yaml_value]):
             ^

./ros2param/api/__init__.py:49:14: C407 Unnecessary list comprehension - 'all' can take a generator.
        elif all([isinstance(v, float) for v in yaml_value]):
             ^

./ros2param/api/__init__.py:52:14: C407 Unnecessary list comprehension - 'all' can take a generator.
        elif all([isinstance(v, str) for v in yaml_value]):
             ^

4     C407 Unnecessary list comprehension - 'all' can take a generator.
1     I100 Import statements are in the wrong order. 'from rcl_interfaces.msg import ParameterType' should be before 'from ros2param.api import get_parameter_value'
5     Q000 Remove bad quotes

[dirk-thomas]

This could assign yaml_value instead which makes the int() call is obsolete.

Same for float below.

[sgvandijk]

Thanks for the review! I've applied the requested changes. I've had a look at the failing build, looks not related to this:

ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml]

[cottsay]

That appears to have been an infrastructure issue with Github that has since been resolved. It was also worked around by ros-infrastructure/rosdep#663.

I'll try to re-trigger the build.

[juanrh]

All these tests are quite similar, so we could merge them in a single parametrized test, that is easier to maintain. Something like

import pytest

@pytest.mark.parametrize("string_value,value_attribute,expected_type,expected_value", [
    ('true', 'bool_value', ParameterType.PARAMETER_BOOL, True),
    ('foo', 'string_value', ParameterType.PARAMETER_STRING, 'foo'),
   ('["foo", "bar", "buzz"]', 'string_array_value', ParameterType.PARAMETER_STRING_ARRAY, ['foo', 'bar', 'buzz'])
])
def test_get_parameter_value(string_value, value_attribute, expected_type, expected_value):
    value = get_parameter_value(string_value=string_value)
    assert value.type == expected_type
    assert getattr(value, value_attribute) is expected_value

[sgvandijk]

I like that, doing that now.

[sgvandijk]

Just to check if there are any more blockers for this PR?

[dirk-thomas]

@sgvandijk Sorry for the late reply. I applied some minor cleanup:

• I removed two obsolete functions in 59c2052
• I updated the test to expect the numeric lists to be of type array.array (which is due to a recent change in the Python mapping, see map Arrays to numpy.ndarray() and Sequences to array.array() rosidl_python#35): 492fba0

CI is looking good:

[dirk-thomas]

Since I made the changes through the web interface the commits were not signed of making the DCO check fail. I took the liberty to force push my last two commits with a proper "Signed-off-by" line.

This is good to be ⛵ now. Thank you for the contribution.