Propose ROS 2 launch front-end design hints. #208

hidmic · 2019-02-06T19:51:25Z

This is a proposal on how to go about implementing something like #207 in an extensible way. Approaches described in here are a combination of ideas I had and ideas that @wjwwood had and shared with me, thus the dual authorship.

I hope that by the time this gets merged we either have chosen one of these approaches or came up with a another one to actually implement.

Signed-off-by: Michel Hidalgo <[email protected]>

wjwwood

Looks like a good start to me.

As for which implementation to use, the one I mostly closely identified with was FDM+, though perhaps this document is just not compelling enough. We might need to discuss off-line to hash out more detail.

Also, a big thing that is missing (but possibly orthogonal to these approaches) is substitutions and how they would be handled.

articles/160_roslaunch_frontend.md

Signed-off-by: Michel Hidalgo <[email protected]>

hidmic · 2019-02-13T17:21:54Z

Also, a big thing that is missing (but possibly orthogonal to these approaches) is substitutions and how they would be handled.

And I think that's exactly why I skipped them in the first place. The document now covers a bit on how substitutions could be handled. PTAL! And thanks for reviewing it in the first place!

wjwwood · 2019-06-27T14:59:54Z

articles/160_roslaunch_frontend.md

+
+### Forward Description Mapping (FDM)
+
+In FDM, the parser relies on a schema and well-known rules to map an static description (markup) to implementation specific instances (objects).


Suggested change

In FDM, the parser relies on a schema and well-known rules to map an static description (markup) to implementation specific instances (objects).

In FDM, the parser relies on a schema and well-known rules to map a static description (markup) to implementation specific instances (objects).

wjwwood · 2019-06-27T15:05:25Z

articles/160_roslaunch_frontend.md

+
+*+* Straightforward to implement.
+
+*+* Launch implementations are completely unaware of the static description existence and its parsing process (to the extent that type agnostic instantiation mechanisms are available).


Suggested change

*+* Launch implementations are completely unaware of the static description existence and its parsing process (to the extent that type agnostic instantiation mechanisms are available).

*+* Launch implementations are completely unaware of the existence of the static description formats and their parsing processes (to the extent that type agnostic instantiation mechanisms are available).

jacobperron · 2019-07-01T20:32:55Z

articles/160_roslaunch_frontend.md

+
+*-* Launch system implementations are aware of the parsing process, being completely involved with it if sugars are to be provided.
+
+*+* Allows leveraging the strenghts of each markup language.


Suggested change

*+* Allows leveraging the strenghts of each markup language.

*+* Allows leveraging the strengths of each markup language.

jacobperron · 2019-07-01T20:33:34Z

articles/160_roslaunch_frontend.md

+
+*+* Allows leveraging the strenghts of each markup language.
+
+*-* Opens the door to big differences in the representation of launch entities across different front end, and even within a given one by allowing the users to introduce multiple custom representations for the same concepts (e.g. a list of numbers).


Suggested change

*-* Opens the door to big differences in the representation of launch entities across different front end, and even within a given one by allowing the users to introduce multiple custom representations for the same concepts (e.g. a list of numbers).

*-* Opens the door to big differences in the representation of launch entities across different front ends, and even within a given one by allowing the users to introduce multiple custom representations for the same concept (e.g. a list of numbers).

Signed-off-by: ivanpauno <[email protected]>

ivanpauno · 2019-07-11T18:59:05Z

@hidmic I addressed the comments, and updated it to match better with the actual implementation (it was actually matching pretty well).

hidmic · 2019-07-12T14:19:39Z

articles/160_roslaunch_frontend.md

@@ -412,9 +418,6 @@ The abstraction layer allows.

 *+* The static description abstraction effectively decouples launch frontends and backends, allowing for completely independent development and full feature availability at zero cost.

-*-* No markup language specific sugars are possible.
-    REVISIT(hidmic): IMHO explicitly disallowing this is a good thing, it makes for more homogeneus descriptions and avoids proliferation of multiple representation of the same concepts (e.g. a list of strings).
-


@ivanpauno this still applies.

hidmic · 2019-07-12T14:20:28Z

articles/160_roslaunch_frontend.md

@@ -336,31 +343,30 @@ Each launch entity that is to be statically described must provide a parsing pro

 *Python*
 ```python
-@launch.expose('some-action')  # Infers it's an Action
+@launch.frontend.expose_action('some-action')  # Infers it's an Action


@ivanpauno I think we should remove # Infers it's an Action.

hidmic · 2019-07-12T14:20:49Z

articles/160_roslaunch_frontend.md

            ]
        )

-@launch.expose('some-subst')  # Infers it's a Substitution
+@launch.frontend.expose_substitution('some-subst')  # Infers it's a Substitution


@ivanpauno I think we should remove # Infers it's a Substitution.

Signed-off-by: ivanpauno <[email protected]>

ivanpauno · 2019-07-12T19:52:21Z

I think this PR is ready. We will deal with event_handlers in the next iteration, but I didn't delete reference to them as this is a design hints document.

* wip * more work in progress * more work done on the calling conventions section * added context section, still a WIP * updated event sections * event filters * fixup even handler subsection * typos * add subsections about the system description (language agnostic) * Proposal for launching dynamically composable nodes (#206) * Proposal for dynamically composed nodes * allow multiple extra_arguments * Allow node_name and namespace to be empty * Human readable error message * Update articles/150_roslaunch.md Co-Authored-By: sloretz <[email protected]> * Assign nodes unique ids, but still forbid duplicates * Update articles/150_roslaunch.md Co-Authored-By: sloretz <[email protected]> * Update articles/150_roslaunch.md Co-Authored-By: sloretz <[email protected]> * Section to list * More generic wording about container processes * namespace -> node_namespace * _launch/ -> ~/_container/ Signed-off-by: Shane Loretz <[email protected]> * Propose ROS 2 launch front-end design hints. (#208) Signed-off-by: Michel Hidalgo <[email protected]> Signed-off-by: ivanpauno <[email protected]> * Adds ROS 2 launch XML format design document (#207) Signed-off-by: Michel Hidalgo <[email protected]> Signed-off-by: ivanpauno <[email protected]> * Update ROS launch documentation (frontend documents) (#247) Signed-off-by: ivanpauno <[email protected]> * review fixup Signed-off-by: William Woodall <[email protected]> * clarify lifecycle transition due to review comment Signed-off-by: William Woodall <[email protected]> * provide rationale for shutdown procedure Signed-off-by: William Woodall <[email protected]> * Add launch XML substitution for a packages share directory (#254) * Add launch XML substitution for a packages share directory Rename find-pkg to find-pkg-prefix. Add find-pkg-share substitution for the share directory. Signed-off-by: Jacob Perron <[email protected]> * remove some old rfc's and general cleanup for first merge Signed-off-by: William Woodall <[email protected]>

Propose ROS 2 launch front-end design hints.

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Signed-off-by: Michel Hidalgo <[email protected]>

hidmic requested review from wjwwood, mjcarroll and sloretz February 6, 2019 19:51

tfoote added the in progress Actively being worked on (Kanban column) label Feb 6, 2019

hidmic added in review Waiting for review (Kanban column) and removed in progress Actively being worked on (Kanban column) labels Feb 6, 2019

cottsay assigned hidmic Feb 7, 2019

Correct ROS 2 launch frontend document style.

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Signed-off-by: Michel Hidalgo <[email protected]>

wjwwood reviewed Feb 13, 2019

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Extend ROS 2 launch frontend document to cover substitutions.

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Signed-off-by: Michel Hidalgo <[email protected]>

hidmic mentioned this pull request Feb 18, 2019

XML/YAML Front-end ros2/launch#163

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ivanpauno mentioned this pull request Apr 15, 2019

Add frontend module in launch, launch_xml and launch_yaml packages ros2/launch#226

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ivanpauno added 2 commits July 11, 2019 15:16

Address review comments

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Signed-off-by: ivanpauno <[email protected]>

Update, to match better with the actual implementation

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Signed-off-by: ivanpauno <[email protected]>

hidmic commented Jul 12, 2019

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Address review comments

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ivanpauno requested review from wjwwood and jacobperron July 12, 2019 19:52

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ivanpauno merged commit cc9b399 into roslaunch Jul 15, 2019

delete-merged-branch bot deleted the hidmic/roslaunch-frontends branch July 15, 2019 15:24

wjwwood mentioned this pull request Jul 23, 2019

ROS 2 Eloquent Elusor ros2/ros2#734

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Propose ROS 2 launch front-end design hints. #208

Propose ROS 2 launch front-end design hints. #208

hidmic commented Feb 6, 2019

wjwwood left a comment

hidmic commented Feb 13, 2019

wjwwood Jun 27, 2019

wjwwood Jun 27, 2019

jacobperron Jul 1, 2019

jacobperron Jul 1, 2019

ivanpauno commented Jul 11, 2019

hidmic Jul 12, 2019

hidmic Jul 12, 2019

hidmic Jul 12, 2019

ivanpauno commented Jul 12, 2019


		### Forward Description Mapping (FDM)

		In FDM, the parser relies on a schema and well-known rules to map an static description (markup) to implementation specific instances (objects).


		+ Straightforward to implement.

		+ Launch implementations are completely unaware of the static description existence and its parsing process (to the extent that type agnostic instantiation mechanisms are available).


		- Launch system implementations are aware of the parsing process, being completely involved with it if sugars are to be provided.

		+ Allows leveraging the strenghts of each markup language.

	+ Allows leveraging the strenghts of each markup language.
	+ Allows leveraging the strengths of each markup language.


		+ Allows leveraging the strenghts of each markup language.

		- Opens the door to big differences in the representation of launch entities across different front end, and even within a given one by allowing the users to introduce multiple custom representations for the same concepts (e.g. a list of numbers).

Propose ROS 2 launch front-end design hints. #208

Propose ROS 2 launch front-end design hints. #208

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