APACHE 2.x ROADMAP
==================
-Last modified at [$Date: 2002/10/19 17:30:15 $]
-
-
-INTRODUCTION
-------------
-The Apache HTTP Server project must balance two competing and disjoint
-objectives: maintain stable code for third party authors, distributors and
-most importantly users so that bug and security fixes can be quickly adopted
-without significant hardship due to user-visible changes; and continue the
-development process that requires ongoing redesign to correct earlier
-oversights and to add additional features.
-
-The Apache HTTP Server, through version 2.0, used the Module Magic Number (MMN)
-to reflect API changes. This had the shortcoming of often leaving users
-hunting to replace binary third party modules that were now incompatible.
-This also left module authors searching through the API change histories to
-determine the exact cause for the MMN change and whether their module was
-affected.
-
-With the simultaneous release of Apache 2.2-stable and Apache 2.3-development,
-the Apache HTTP Server project is moving towards a more predictable stable
-release cycle, while allowing forward progress to occur without concern
-for breaking the stable branch. This document explains the rationale between
-the two versions and their behavior.
-
-
-STABLE RELEASES, 2.{even}.{revision}
-------------------------------------
-
-All even numbered releases will be considered stable revisions.
-
-Stable revisions will retain forward compatiblity to the maximum
-possible extent. Features may be added during minor revisions, and
-features may be deprecated by making appropriate notations in the
-documentation, but no features may be removed.
-
-In essence, that implies that you can upgrade from one minor revision
-to the next with a minimum of trouble. In particular, this means:
-
- * The Module API will retain forward compatibility.
- It will not be necessary to update modules to work with new
- revisions of the stable tree.
-
- * The run-time configuration will be forward compatible.
- No configuration changes will be necessary to work with new
- revisions of the stable tree.
-
- * Compile-time configuration will be forward compatible.
- The configure command line options that work in one release
- of the stable tree will also work in the next release.
-
-As always, it will be necessary to test any new release to assure
-that it works correctly with a particular configuration and a
-particular set of modules, but every effort will be made to assure
-that upgrades are as smooth as possible.
-
-In addition, the following development restrictions will aid in
-keeping the stable tree as safe as possible:
-
- * No 'Experimental' modules; while it may be possible (based on API changes
- required to support a given module) to load a 2.3-development module into
- a 2.2-stable build of Apache, there are no guarantees. Experimental
- modules will be introduced to the 2.3-development versions and either
- added to 2.2-stable once they are proven and compatible, or deferred
- to the 2.4-stable release if they cannot be incorporated in the current
- stable release due to API change requirements.
-
- * The stable CVS tree should not remain unstable at any time. Atomic commits
- aught be used to introduce code from the development version to the stable
- tree. At any given time a security release may be in preparation,
- unbeknownst to other contributors. At any given time, testers may be
- checking out CVS head to confirm that a bug has been corrected. And as
- all code was well-tested in development prior to committing to the stable
- tree, there is really no reason for this tree to be broken for more than
- a few minutes during a lengthy commit.
-
-In order to avoid 'skipped' release numbers in the stable releases, the
-Release Manager will generally roll a release candidate (APACHE_#_#_#_RC#)
-tag. Release Candidate tarballs will be announced to the
-stable-testers@httpd.apache.org for the stable tree. Then, the participants
-will vote on the quality of the proposed release tarball.
-
-The final APACHE_#_#_# tag will not exist until the APACHE_#_#_#_RC# candidate
-has passed the usual votes to release that version. Only then is the final
-tarball packaged, removing all -rc# designations from the version number, and
-tagging the tree with the release number.
-
-DEVELOPMENT RELEASES, 2.{odd}.{revision}
------------------------------------------
-
-All odd numbered releases designate the 'next' possible stable release,
-therefore the current development version will always be one greater than
-the current stable release. Work proceeds on development releases, permitting
-the modification of the MMN at any time in order to correct deficiencies
-or shortcomings in the API. This means that modules from one development
-release to another may not be binary compatible, or may not successfully
-compile without modification to accomodate the API changes.
-
-The only 'supported' development release at any time will be the most
-recently released version. Developers will not be answering bug reports
-of older development releases once a new release is available. It becomes
-the resposibility of the reporter to use the latest development version
-to confirm that any issue still exists.
-
-Any new code, new API features or new ('experimental') modules may be
-promoted at any time to the next stable release, by a vote of the project
-contributors. This vote is based on the technical stability of the new
-code and the stability of the interface. Once moved to stable, that feature
-cannot change for the remainder of that stable release cycle, so the vote must
-reflect that the final decisions on the behavior and naming of that new
-feature were reached. Vetos continue to apply to this choice of introducing
-the new work to the stable version.
-
-At any given time, when the quality of changes to the development branch
-is considered release quality, that version may become a candidate for the
-next stable release. This includes some or all of the API changes, promoting
-experimental modules to stable or deprecating and eliminating older modules
-from the last stable release. All of these choices are considered by the
-project as a group in the interests of promoting the stable release, so that
-any given change may be 'deferred' for a future release by the group, rather
-than introduce unacceptable risks to adopting the next stable release.
-
-Third party module authors are strongly encouraged to test with the latest
-development version. This assures that the module will be ready for the next
-stable release, but more importantly, the author can react to shortcomings
-in the API early enough to warn the dev@httpd.apache.org community of the
-shortcomings so that they can be addressed before the stable release. The
-entire burden is on the module author to anticipate the needs of their module
-before the stable release is created. Once a new stable release cycle has
-begun, that API will be present for the lifetime of the stable release. Any
-desired changes in the stable versions must wait for inclusion into the next
-release cycle.
-
-In order to ease the burden of creating development releases, the process
-for packaging a development releases is less formal than for the stable
-release. This strategy reflects the fact that while in development, versions
-are cheap. Development releases may be classified as alpha, beta, or GA
-to reflect the group's perceived stability of the tree. Development releases
-may be made at any time by any committer.
-
-Please read the following link for a more detailed description of the
-development release strategy:
-
-http://httpd.apache.org/dev/release.html
+Last modified at [$Date$]
WORKS IN PROGRESS
Remember, it just takes cvs diff -b (that is, --ignore-space-change)
to see the code changes and ignore that cruft. Get editing Justin :)
- * revamp the input filter syntax to provide for ordering of
- filters created with the Set{Input|Output}Filter and the
- Add{Input|Output}Filter directives. A 'relative to filterx'
- syntax is definately preferable.
-
- * Platforms that do not support fork (primarily Win32 and AS/400)
- Architect start-up code that avoids initializing all the modules
- in the parent process on platforms that do not support fork.
-
- . Better yet - not only inform the startup of which phase it's in,
- but allow the parent 'process' to initialize shared memory, etc,
- and create a module-by-module stream to pass to the child, so the
- parent can actually arbitrate the important stuff.
-
* Replace stat [deferred open] with open/fstat in directory_walk.
Justin, Ian, OtherBill all interested in this. Implies setting up
the apr_file_t member in request_rec, and having all modules use
available for the life of the request, so a complete
async implementation would need to happen 3.0 release.
- * Add a string "class" that combines a char* with a length
- and a reference count. This will help reduce the number
- of strlen and strdup operations during request processing.
- Including both the length and allocation will save us a ton
- of reallocation we do today, in terms of string manipulation.
-
- OtherBill asks if this is really an APR issue, not an HTTPD issue?
+ Brian notes that async writes will provide a bigger
+ scalability win than async reads for most servers.
+ We may want to try a hybrid sync-read/async-write MPM
+ as a next step. This should be relatively easy to
+ build: start with the current worker or leader/followers
+ model, but hand off each response brigade to a "completion
+ thread" that multiplexes writes on many connections, so
+ that the worker thread doesn't have to wait around for
+ the sendfile to complete.
MAKING APACHE REPOSITORY-AGNOSTIC
than calling apr_dir_open/read/close(), a caller uses
resource->repos->get_children() or somesuch.
- Note that things like mod_dir, mod_autoindex, and mod_negotation
+ Note that things like mod_dir, mod_autoindex, and mod_negotiation
need to be converted to use these mechanisms so that their
functions will work on logical repositories rather than just
filesystems.
projects / apache / blobdiff