Difference between revisions of "App Store Technical Requirements"

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{{TOC}}
 
{{TOC}}
  
= Goals =
+
= Background =
  
The long-term goal is to move ns-3 to separate modules, for build and  
+
The goal is to support modularization of the ns-3 code base and federation of development activitiesTo date, the main path to distributing extensions to ns-3 has been to request a code review for merge to the mainline tree.  The future goal is to shrink the ns-3 core, and to better facilitate modules that are independently developed and maintained.  As a concrete example, the [https://www.r-project.org/ R statistical framework] does not integrate every extension to its main release; instead, it allows users to [https://cran.cnr.berkeley.edu/web/packages/available_packages_by_date.html fetch the packages of interest] and add to their installationCommunities-of-interest have even arisen to allow researchers to organize and curate sets of R extensions (e.g. [https://www.bioconductor.org/ bioinformatic packages]).  We envision the same for ns-3.
maintenance reasonsFor build reasons, since ns-3 is becoming large,  
+
we would like to allow users to enable/disable subsets of the available
+
model libraryFor maintenance reasons, it is important that we move to  
+
a development model where modules can evolve on different timescales and  
+
be maintained by different organizations.
+
  
An analogy is the GNOME desktop, which is composed of a number of
+
In the ns-3.27 release, the bake build orchestration tool was extended to allow third party contributed code modules to be added to ns-3, and to be downloaded, built, and installed with the main ns-3 releaseThis allows modules to be hosted elsewhere and integrated with the ns-3-allinone framework. Consider this to be the back-end support for modularization.  We have not gone further since that time.
individual libraries that evolve on their own timescalesA build
+
framework called [http://live.gnome.org/Jhbuild jhbuild] exists for
+
building and managing the dependencies between these disparate projects.
+
  
Once we have a modular build, and an ability to separately download and
+
For example, the sift routing code contribution has been added as a modulePlease review how users are expected to add sift to their ns-3.27 release [[BakeIntegration | on this wiki page]].
install third-party modules, we will need to distinguish the maintenance
+
status or certification of modulesThe ns-3 project will maintain a
+
set of core ns-3 modules including those essential for all ns-3
+
simulations, and will maintain a master build file containing metadata
+
to contributed modules; this will allow users to fetch and build what
+
they need.  Eventually, modules will have a maintenance state associated
+
with them describing aspects such as who is the maintainer, whether it
+
is actively maintained, whether it contains documentation or tests,
+
whether it passed an ns-3 project code review, whether it is currently
+
passing the tests, etc. The current status of all known ns-3 modules
+
will be maintained in a database and be browsable on the project web site.
+
  
[[image:Maintenance-status-example.PNG]]
+
There are two main components:
  
'''Figure caption''':  ''Mock-up of future model status page (models and colors selected are just for example purposes)''
+
1) '''front end''' The ns-3 app store (https://apps.nsnam.org) is largely operational and will be put into actual use for ns-3.29.  The app store can be used to directly download contributed modules, and to post information about the module.
  
The basic idea of the ns-3 app store would be to store on a server a set of user-submitted metadata which describes various source code packages. Typical metadata would include:
+
2) '''back end''' The back end will be the [https://www.nsnam.org/docs/bake/tutorial/html/bake-over.html bake build orchestration tool].
* unique name
+
* version number
+
* last known good ns-3 version (tested against)
+
* description
+
* download url
+
* untar/unzip command
+
* configure command
+
* build command
+
* system prerequisites (if user needs to apt-get install other libraries)
+
* list of ns-3 package dependencies (other ns-3 packages which this package depends upon)
+
  
 +
= Workflows =
 +
 +
We envision three types of users:
 +
 +
#. '''End user:'''  The normal user will browse to the app store to learn about available apps, learn about resources (user forums, documentation) about each app, and possibly leave feedback on a review board.  The normal user will obtain the necessary information to fetch and install each app from this page.
 +
#. '''Developer:'''  Developers will not be able to create new apps on the app store, but will be able to edit the app page that he or she owns. To make an app available on the store, it has to go through an ns-3 review process.
 +
#. '''Maintainer:''' ns-3 maintainers will create a new page for an accepted app, and create a developer account for the author. Then the developer will be able to edit the page to suit their app.
 +
 
 
= Requirements =
 
= Requirements =
 +
The following requirements were used to develop the app store (https://apps.nsnam.org).
  
== Build and configuration ==
+
#. The front page should be clean, consisting of categories, newest releases, and popular downloads.
 +
#. Each "app" will be an ns-3 module, with a description page including:  Description, screenshots (optional),  download tab, resources tab, etc.
 +
#. Clear documentation must be posted on how to use the app store, and how to submit a new app to the app store
 +
#. The "Download" tab will fetch a source archive, and the user will download to a location of their choice.  The user is responsible for moving or copying the package to their ns-3 development directory, and then the ns-3 build tools (invoked at command line by users in the normal way) will do the rest.
 +
#. XML for the bake configuration will also be maintained for each module, allowing module contributors to post new releases of their module.
  
* Enable optimized, debug, and static builds
+
= Enhancements =
* Separate tests from models
+
* Doxygen support
+
* Test.py framework supports the modularization
+
* Python bindings support the modularization
+
* integrate lcov code coverage tests
+
* integrate with buildbots
+
  
== API and work flow ==
+
Once the basic capability is deployed, enhancements are possible.  Some of these extensions may involve modifying the app store installation, but some will involve modifying ns-3 build scripts, documentation, and other scripts (e.g. Jenkins scripts).
  
Assume that our download script is called download.py and our
+
== Integration with bake ==
build script is called build.py.
+
  
  wget http://www.nsnam.org/releases/ns-allinone-3.x.tar.bz2
+
Bake uses XML to describe modules. It would be nice to have a standardized XML schema that describes an ns-3 module, and make it usable from both the app store and from bake. For instance, there could be an "authors" field in the XML description that can be displayed by bake at the command line and can also be parsed and shown as the Authors in the app store description.
  bunzip2 ns-allinone-3.x.tar.bz2 && tar xvf ns-allinone-3.x.tar.bz2
+
  cd ns-allinone-3.x
+
  
In this directory, users will find the following directory layout:
+
== User feedback and comments ==
  
  build.py download.py constants.py? VERSION LICENSE README
+
We probably want to explore and tailor the capability for users to provide feedback and hints about apps. We do not want the capability to be abused by spammers (e.g. a captcha?).
  
Download essential modules:
+
== Documentation and module creation scripts ==
  
  ./download.py
+
* Doxygen and Sphinx scripts should be modified to allow building on a per-module basis; ns-3 web site should still integrate all of these module documentations coherently
 +
* The create-module.py program should be updated
 +
* The ns-3 tutorial must be updated
  
This will leave a layout such as follows:
+
== Regression testing ==
  
  download.py build.py pygccxml pybindgen simulator core common gcc-xml
+
We need to write some new [https://ns-buildmaster.ee.washington.edu:8010/ Jenkins scripts] to test the known modules for regressions.
  
For typical users, the next step is as follows:
+
== Versioning ==
  
  ./build.py ns3
+
Managing the version numbers of different apps will be necessary. We want users to be able to declare that apps are compatible with specific ns-3 versions.
  
"ns3" is a meta-module that pulls in what constitutes what is considered
+
== Patch management ==
to be the core of an ns-3 release (i.e. for starters, every module that is
+
in ns-3.9).
+
  
The above will take the following steps:
+
Apps may fall out of date (become unmaintained) but it may be the case that some simple patches could be applied on top of them to make them workable again with the latest ns-3.  The framework should support the ability to declare that a module installation consists of downloading an archive and then patching it with a file fetched from elsewhere. A module may also require patching of ns-3 core itself; the framework should support this.
* build all typical prerequisites such as pybindgen
+
* cd core
+
* ./waf configure && ./waf && ./waf install
+
  
The above will install headers into build/debug/ns3/ and a libns3core.so
+
== Dependency management ==
into build/debug/lib/
+
  
  cd ../simulator
+
If some modules depend on other modules or system dependencies, that needs to be expressed and handled by the tools. This is mainly a bake build issue, but it probably requires also some documentation in the app store that the module depends, for example, on a system library such as Boost.
  ./waf configure && ./waf && ./waf install
+
  cd ..
+
  ...
+
  
'''Open issue:''' What granularity of modules should we maintain?  Continue
+
== Module grouping ==
with core, simulator, common, node?  Merge them somehow?
+
  
'''Open issue:''' How to express and honor platform limitations, such as
+
We will probably want support for groups of modules.  Users should be able to specify, for example, "Ad hoc routing" and fetch modules for several protocols, which may be hosted at different sites.
only trying to download/build NSC on platforms supporting it.
+
  
Once the build process is done, there will be a bunch of libraries in a
+
= contrib module requirements for ns-3.29 =
common build directory, and all applicable headers.  Specifically,
+
we envision for module foo, there may be a libns3foo.so, libns3foo-test.so,
+
a python .so, and possibly others.
+
  
=== Python ===
+
== Goals ==
  
We have a few choices for supporting Python. First, note that this type
+
1. The source code layout of a module is the same as a module found in the <code>src</code> directory of ns-3:
of system provides an opportunity for the python build tools to be added
+
as packages to the overall build system, so that users can more easily
+
build their bindings.  We can try to build lots of small python modules,
+
or run a scan at the very end of the ns-3 build process to build a customized
+
python ns3 module, such as:
+
  
* python-scan.py
+
  bindings doc examples helper model test wscript
* ...
+
* pybindgen
+
  
which operates on the headers in the build/debug/ns3 directory and creates
+
2.  Additionally, the module must contain two version files.  <code>VERSION</code> is the version number of the module, and should be a conventional sequence-based identifier (such as '1.0.0') allowing users to easily interpret older and newer versions.  <code>NS3-VERSION</code> is a recommended or known-good version of ns-3 with which the module is compatible, and should just be a single line.
a python module .so library that matches the ns-3 configured components.
+
 
    
+
   release <release tag number>
'''Open issue:''' What is the eventual python API?  Should each module be
+
 
imported separately such as import node as ns.node, or should we try to
+
or  
go for a single ns3 python module?
+
 
 +
  changeset <mercurial changeset hash>
  
Or, we could continue to maintain bindings.  Another consideration is that
+
Examples:
constantly generating bindings will slow down the builds.
+
  
=== Tests ===
+
  release ns-3.28
  
Tests are run by running ./test.py, which knows how to find the available
+
  changeset 13418:82d130348a36
test libraries and run the tests.
+
  
Presently, test.py hardcodes the examples or samples; it needs to become
+
The build system will use the NS3-VERSION to warn of possible incompatibilities.
smarter to learn what examples are around and need testing.
+
  
=== Doxygen ===
+
3.  The source code must be provided from a hosting provider such as GitHub or Bitbucket, or as an source archive downloadable from the web.  The module should be provided such that it can be cloned directly (or untarred) into the contrib directory without cloning also the upstream ns-3-dev repository.
  
Doxygen can be run such as "build.py doxygen" on the build/debug/ns3
+
For example:
directory.  I would guess that we don't try to modularize this but instead
+
to run on the build/debug/ns3/ directory once all headers have been copied in.
+
  
=== Build flags ===
+
  $ cd ns-3-allinone/ns-3-dev/contrib
 +
  $ git clone https://github.com/sampleuser/sample-module
 +
  $ ls sample-module
 +
  bindings doc examples helper model NS3-VERSION test VERSION
  
To configure different options such as -g, -fprofile-arcs, e.g., use the
+
4. The module should be named in lowercase with hyphen separation of words, similar to ns-3 <code>src</code> directory conventions.
CFLAGS environment variable.
+
  
=== Running programs ===
+
5.  All module C++ source code should be put into a separate C++ namespace within ns3 namespace, corresponding to the module name, similar to how ns-3's aodv and olsr are structured.
  
To run programs:
+
5.  ns-3's <code>create-module.py</code> should be moved to the contrib/ directory, and documentation updated to describe this change.
  
  ./build.py shell
+
== Non-goals ==
  build/debug/examples/csma/csma-bridge
+
or
+
  python build/debug/examples/csma/csma-bridge.py
+
  
=== Other examples ===
+
The below are non-goals for ns-3.29 release, although they may be worked on for future releases.
  
Build all known ns-3 modules:
+
1.  provide build scripts so that each module can be built, tested, and installed as a completely standalone library without invoking ns-3's Waf, although this will not be precluded if a user wishes to provide some build scripts to do so.
  
  ./build.py all
+
2. provide build scripts to build the module Doxygen separately from the rest of ns-3 (perhaps this could be supported in ns-3.29 if someone can work on it).  
  
In the above case, suppose that the program could not download and fetch
+
3.  support modules that require patching of the mainline ns-3 release to functionWe could experiment with including a <code>patches</code> directory that can store patches for the mainline that must be applied by bake.
a moduleHere, it can interactively prompt the user "Module foo not
+
found; do you wish to continue [Y/n]?".
+
  
Build the core of ns-3, plus device models WiFi and CSMA:
+
= Packaging for ns-3.29 release =
  
  ./build ns3-core wifi csma
+
The <code>ns-allinone-3.29</code> release tarball will contain all modules (the universe) supported for ns-3.29 and found in the app store.  However, the default build of ns-3.29 will exclude the contributed modules. 
  
ns3-core is a meta-module containing simulator core common node. 
+
We may decide to later release subsets of the universe of modules (such as the so-called 'spins' of Linux desktop distros), but for simplicity's sake for ns-3.29, we will just include all.
'''Open issue:''' what is the right granularity for this module?
+
  
Suppose a research group at Example Univ. publishes a new WiMin device
+
We may decide to migrate some relatively unused existing ns-3 modules from <code>src</code> to <code>contrib</code> at release time, to shrink the default build.
module.  It gets a new unique module name from ns-3 project, such as
+
wimin.  It also contributes metadata to the master ns-3 build script.  
+
When a third-party does the following:
+
  
  ./build.py wimin
+
Proposed API:
  
the system will try to download and build the new wimin module (plus its
+
  # by default, will exclude contrib modules:
examples and tests), and put it in the usual place.
+
  $ ./waf configure --enable-examples --enable-tests
 +
  # selectively include sample-module in the usual way:
 +
  $ ./waf configure --enable-examples --enable-tests --enable-modules=core,network,lte,sample-module
 +
  # include all src and contrib modules meeting dependency requirements:
 +
  $ ./waf configure --enable-examples --enable-tests --enable-modules=all
  
= Plan =
+
= Development workflow for contrib modules =
  
GNOME jhbuild seems to be able to provide most or all of the "build.py"
+
The usual way for people to work on a new feature has been to fork ns-3-dev and either edit existing modules or create new modules in <code>src</code>This results in a parallel repository to ns-3-dev, completely stand-alone from ns-3-dev.
and "download.py" functionality mentioned abovejhbuild may need to be
+
wrapped by a specialized ns-3 build.py or download.py wrapper.    So,  
+
the current plan is to try to prototype the above using jhbuild and se
+
how far we get
+
  
Work can proceed in parallel:
+
In the new model, authors will create standalone module repositories and will need to place them within the contrib/ folder of ns-3 to work on them.
  
# Start to try to compare jhbuild with our existing download.py/build.py at the top level directory
+
Will [https://gist.github.com/gitaarik/8735255 Git submodules] be the preferred recommended way for people to set up a contrib development environment?  Someone should investigate this or propose alternatives.
# Try to define the module granularity and fix broken module dependencies
+
# Work on python bindings
+
# Work on how to handle examples in a modular test framework
+

Latest revision as of 15:21, 19 April 2018

Main Page - Current Development - Developer FAQ - Tools - Related Projects - Project Ideas - Summer Projects

Installation - Troubleshooting - User FAQ - HOWTOs - Samples - Models - Education - Contributed Code - Papers

Background

The goal is to support modularization of the ns-3 code base and federation of development activities. To date, the main path to distributing extensions to ns-3 has been to request a code review for merge to the mainline tree. The future goal is to shrink the ns-3 core, and to better facilitate modules that are independently developed and maintained. As a concrete example, the R statistical framework does not integrate every extension to its main release; instead, it allows users to fetch the packages of interest and add to their installation. Communities-of-interest have even arisen to allow researchers to organize and curate sets of R extensions (e.g. bioinformatic packages). We envision the same for ns-3.

In the ns-3.27 release, the bake build orchestration tool was extended to allow third party contributed code modules to be added to ns-3, and to be downloaded, built, and installed with the main ns-3 release. This allows modules to be hosted elsewhere and integrated with the ns-3-allinone framework. Consider this to be the back-end support for modularization. We have not gone further since that time.

For example, the sift routing code contribution has been added as a module. Please review how users are expected to add sift to their ns-3.27 release on this wiki page.

There are two main components:

1) front end The ns-3 app store (https://apps.nsnam.org) is largely operational and will be put into actual use for ns-3.29. The app store can be used to directly download contributed modules, and to post information about the module.

2) back end The back end will be the bake build orchestration tool.

Workflows

We envision three types of users:

  1. . End user: The normal user will browse to the app store to learn about available apps, learn about resources (user forums, documentation) about each app, and possibly leave feedback on a review board. The normal user will obtain the necessary information to fetch and install each app from this page.
  2. . Developer: Developers will not be able to create new apps on the app store, but will be able to edit the app page that he or she owns. To make an app available on the store, it has to go through an ns-3 review process.
  3. . Maintainer: ns-3 maintainers will create a new page for an accepted app, and create a developer account for the author. Then the developer will be able to edit the page to suit their app.

Requirements

The following requirements were used to develop the app store (https://apps.nsnam.org).

  1. . The front page should be clean, consisting of categories, newest releases, and popular downloads.
  2. . Each "app" will be an ns-3 module, with a description page including: Description, screenshots (optional), download tab, resources tab, etc.
  3. . Clear documentation must be posted on how to use the app store, and how to submit a new app to the app store
  4. . The "Download" tab will fetch a source archive, and the user will download to a location of their choice. The user is responsible for moving or copying the package to their ns-3 development directory, and then the ns-3 build tools (invoked at command line by users in the normal way) will do the rest.
  5. . XML for the bake configuration will also be maintained for each module, allowing module contributors to post new releases of their module.

Enhancements

Once the basic capability is deployed, enhancements are possible. Some of these extensions may involve modifying the app store installation, but some will involve modifying ns-3 build scripts, documentation, and other scripts (e.g. Jenkins scripts).

Integration with bake

Bake uses XML to describe modules. It would be nice to have a standardized XML schema that describes an ns-3 module, and make it usable from both the app store and from bake. For instance, there could be an "authors" field in the XML description that can be displayed by bake at the command line and can also be parsed and shown as the Authors in the app store description.

User feedback and comments

We probably want to explore and tailor the capability for users to provide feedback and hints about apps. We do not want the capability to be abused by spammers (e.g. a captcha?).

Documentation and module creation scripts

  • Doxygen and Sphinx scripts should be modified to allow building on a per-module basis; ns-3 web site should still integrate all of these module documentations coherently
  • The create-module.py program should be updated
  • The ns-3 tutorial must be updated

Regression testing

We need to write some new Jenkins scripts to test the known modules for regressions.

Versioning

Managing the version numbers of different apps will be necessary. We want users to be able to declare that apps are compatible with specific ns-3 versions.

Patch management

Apps may fall out of date (become unmaintained) but it may be the case that some simple patches could be applied on top of them to make them workable again with the latest ns-3. The framework should support the ability to declare that a module installation consists of downloading an archive and then patching it with a file fetched from elsewhere. A module may also require patching of ns-3 core itself; the framework should support this.

Dependency management

If some modules depend on other modules or system dependencies, that needs to be expressed and handled by the tools. This is mainly a bake build issue, but it probably requires also some documentation in the app store that the module depends, for example, on a system library such as Boost.

Module grouping

We will probably want support for groups of modules. Users should be able to specify, for example, "Ad hoc routing" and fetch modules for several protocols, which may be hosted at different sites.

contrib module requirements for ns-3.29

Goals

1. The source code layout of a module is the same as a module found in the src directory of ns-3:

 bindings doc examples helper model test wscript

2. Additionally, the module must contain two version files. VERSION is the version number of the module, and should be a conventional sequence-based identifier (such as '1.0.0') allowing users to easily interpret older and newer versions. NS3-VERSION is a recommended or known-good version of ns-3 with which the module is compatible, and should just be a single line.

 release <release tag number>

or

 changeset <mercurial changeset hash>

Examples:

 release ns-3.28
 changeset 13418:82d130348a36

The build system will use the NS3-VERSION to warn of possible incompatibilities.

3. The source code must be provided from a hosting provider such as GitHub or Bitbucket, or as an source archive downloadable from the web. The module should be provided such that it can be cloned directly (or untarred) into the contrib directory without cloning also the upstream ns-3-dev repository.

For example:

 $ cd ns-3-allinone/ns-3-dev/contrib
 $ git clone https://github.com/sampleuser/sample-module
 $ ls sample-module
 bindings doc examples helper model NS3-VERSION test VERSION

4. The module should be named in lowercase with hyphen separation of words, similar to ns-3 src directory conventions.

5. All module C++ source code should be put into a separate C++ namespace within ns3 namespace, corresponding to the module name, similar to how ns-3's aodv and olsr are structured.

5. ns-3's create-module.py should be moved to the contrib/ directory, and documentation updated to describe this change.

Non-goals

The below are non-goals for ns-3.29 release, although they may be worked on for future releases.

1. provide build scripts so that each module can be built, tested, and installed as a completely standalone library without invoking ns-3's Waf, although this will not be precluded if a user wishes to provide some build scripts to do so.

2. provide build scripts to build the module Doxygen separately from the rest of ns-3 (perhaps this could be supported in ns-3.29 if someone can work on it).

3. support modules that require patching of the mainline ns-3 release to function. We could experiment with including a patches directory that can store patches for the mainline that must be applied by bake.

Packaging for ns-3.29 release

The ns-allinone-3.29 release tarball will contain all modules (the universe) supported for ns-3.29 and found in the app store. However, the default build of ns-3.29 will exclude the contributed modules.

We may decide to later release subsets of the universe of modules (such as the so-called 'spins' of Linux desktop distros), but for simplicity's sake for ns-3.29, we will just include all.

We may decide to migrate some relatively unused existing ns-3 modules from src to contrib at release time, to shrink the default build.

Proposed API:

 # by default, will exclude contrib modules:
 $ ./waf configure --enable-examples --enable-tests  
 # selectively include sample-module in the usual way:
 $ ./waf configure --enable-examples --enable-tests --enable-modules=core,network,lte,sample-module
 # include all src and contrib modules meeting dependency requirements:
 $ ./waf configure --enable-examples --enable-tests --enable-modules=all

Development workflow for contrib modules

The usual way for people to work on a new feature has been to fork ns-3-dev and either edit existing modules or create new modules in src. This results in a parallel repository to ns-3-dev, completely stand-alone from ns-3-dev.

In the new model, authors will create standalone module repositories and will need to place them within the contrib/ folder of ns-3 to work on them.

Will Git submodules be the preferred recommended way for people to set up a contrib development environment? Someone should investigate this or propose alternatives.