| Prev | Chapter�17.�Kernel Documentation | Next |
|---|
By Bryan Quinn
+Tcl API
Tcl API
apm-install-procs.tcl (Supports installation of packages)
20-apm-load-procs.tcl (Bootstraps APM for server startup)
-apm-admin-procs.tcl (Supports APM UI)
PL/SQL file
PL/SQL file
+In general terms, a package is a unit of software that serves a single well-defined purpose. That purpose may be to provide a service directly to one or more classes of end-user, (e.g., discussion forums and file storage for community members, user profiling tools for the site publisher), or it may be to act as a building block for other packages (e.g., an application programming interface (API) for storing and querying access control rules, or an API for scheduling email alerts). Thus, packages fall into one of two categories: -
OpenACS Applications: a "program or group of programs -designed for end users" (the Webopedia +
OpenACS Applications: a "program or group of programs +designed for end users" (the Webopedia definition); also known as modules, for historical reasons. Examples of applications include Forums and News. -
OpenACS Services: the aforementioned building blocks. +
OpenACS Services: the aforementioned building blocks. Examples of services include the OpenACS Content Repository, the OpenACS Templating -System, and the OpenACS Kernel, which includes +System, and the OpenACS Kernel, which includes APM.
An installation of the OpenACS includes the OpenACS Kernel, some services that extend the kernel's functionality, and some applications intended for end-users. Packages function as individual pieces of subsites. A subsite can contain multiple @@ -43,7 +42,7 @@ installation through APM is another potential package instance that can become part of Jane's View Camera subsite.
The APM provides an architecture for packaging software, making instances of that software available to subsites, specifying configuration parameters -for each instance, and managing the creation and release of new packages.
+for each instance, and managing the creation and release of new packages.
Prior to ACS 3.3, all packages were lumped together into one monolithic distribution without explicit boundaries; the only way to ascertain what comprised a given package was to look at the top of the corresponding @@ -88,21 +87,21 @@ packages for other OpenACS users to download and install.
For a simple illustration of the difference between ACS without APM (pre-3.3) and ACS with APM (3.3 and beyond), consider a hypothetical ACS installation that uses only two of the thirty-odd modules available circa ACS -3.2 (say, bboard and e-commerce):
APM itself is part of a package, the OpenACS Kernel, an OpenACS -service that is the only mandatory component of an OpenACS installation.
The OpenACS is a platform for web-based application software, and any software +3.2 (say, bboard and e-commerce):
APM itself is part of a package, the OpenACS Kernel, an OpenACS +service that is the only mandatory component of an OpenACS installation.
The OpenACS is a platform for web-based application software, and any software platform has the potential to develop problems like those described above. Fortunately, there are many precedents for systematic solutions, including:
Borrowing from all of the above, OpenACS 3.3 introduces its own package -management system, the OpenACS Package Manager (APM), which consists of:
a standard format for APM packages (also called -"OpenACS packages"), including:
version numbering, independent of any other package and the OpenACS as a -whole
specification of the package interface
specification of dependencies on other packages (if any)
attribution (who wrote it) and ownership (who maintains it)
web-based tools for package management:
obtaining packages from a remote distribution point
installing packages, if and only if:
all prerequisite packages are installed
no conflicts will be created by the installation
configuring packages (obsoleting the monolithic OpenACS configuration -file)
upgrading packages, without clobbering local modifications
uninstalling unwanted packages
a registry of installed packages, database-backed and +management system, the OpenACS Package Manager (APM), which consists of:
a standard format for APM packages (also called +"OpenACS packages"), including:
version numbering, independent of any other package and the OpenACS as a +whole
specification of the package interface
specification of dependencies on other packages (if any)
attribution (who wrote it) and ownership (who maintains it)
web-based tools for package management:
obtaining packages from a remote distribution point
installing packages, if and only if:
all prerequisite packages are installed
no conflicts will be created by the installation
configuring packages (obsoleting the monolithic OpenACS configuration +file)
upgrading packages, without clobbering local modifications
uninstalling unwanted packages
a registry of installed packages, database-backed and integrated with filesystem-based version control -
web-based tools for package development:
creating new packages locally
releasing new versions of locally-created packages
The design chosen for APM was meant to satisfy the following constraints:
The process of authoring a package must be as simple as possible.
Strict conventions must be established that provide a set of canonical locations and names for files and patterns, for OpenACS application @@ -121,9 +120,9 @@ documentation walks the developer through each of these steps. Moreover, from following these steps, the package can be subsite specific, available to subsites across the system, and be available for distribution to other OpenACS -installations without doing a monolithic upgrade or reinstall.
The APM is composed of systems for accomplishing a set of package-related +installations without doing a monolithic upgrade or reinstall.
The APM is composed of systems for accomplishing a set of package-related tasks. Each of these tasks comprise a feature area that has an API, data -model, and a UI:
Authoring a Package
Maintaining Multiple Versions of a Package
Creating Instances of the Package
Specifying Configuration Parameters for each Instance
Authoring a Package
Full instructions on how to prepare an OpenACS package are available in Packages. The API here can be invoked manually by a package's data model +model, and a UI:
Authoring a Package
Maintaining Multiple Versions of a Package
Creating Instances of the Package
Specifying Configuration Parameters for each Instance
Authoring a Package
Full instructions on how to prepare an OpenACS package are available in Packages. The API here can be invoked manually by a package's data model creation script, but need not to be used. This API is part of the APM PL/SQL package.
@@ -144,9 +143,9 @@
The procedure above registers an OpenACS application in the APM. It creates a new OpenACS object and stores information about the package, such as its name, in the APM data model. There is an analogous procedure for OpenACS services, called -apm.register_service.
To remove an application from the system, there are the calls -apm.unregister_application and -apm.unregister_service.
+apm.register_service.To remove an application from the system, there are the calls +
apm.unregister_applicationand +apm.unregister_service.-- Remove the application from the system. procedure unregister_application ( @@ -155,22 +154,22 @@ cascade_p in char default 'f' ); -Use the cascade_p only if you want to completely remove the +
Use the cascade_p only if you want to completely remove the
package from the OpenACS.
In order to determine if a particular package exists in the system, use -the register_p predicate. It returns 1 if the specified -package_key exists in the system, 0 otherwise.
+theregister_ppredicate. It returns 1 if the specified +package_keyexists in the system, 0 otherwise.function register_p ( package_key in apm_package_types.package_key%TYPE ) return integer; -Maintaining Multiple Versions of a Package
While the package authoring API provides a means for registering a +
Maintaining Multiple Versions of a Package
While the package authoring API provides a means for registering a package, some information about a package is version dependent. For example, between versions, the owner of a package, its vendor, its URI, and its dependency information may change. The API for package versions allows this information to be specified. All of these APIs are part of the -apm_package_version PL/SQL package.
To create a new package version, use the -apm_package_version.new constructor function.
+apm_package_versionPL/SQL package.To create a new package version, use the +
apm_package_version.newconstructor function.function new ( version_id in apm_package_versions.version_id%TYPE @@ -191,26 +190,26 @@ default 'f' ) return apm_package_versions.version_id%TYPE; -In order to use this function, an existing package_key must -be specified. The version_name parameter must follow a strict +
In order to use this function, an existing package_key must
+be specified. The version_name parameter must follow a strict
convention:
A major version number
at least one minor version number. Although any number of minor version numbers may be included, three minor version numbers is sufficient and is the -convention of software developers.
One of the following:
The letter d, indicating a development-only version
The letter a, indicating an alpha release
The letter b, indicating a beta release
No letter at all, indicating a final production release
In addition, the letters d, a, and -b may be followed by another integer, indicating a version +convention of software developers.
One of the following:
The letter d, indicating a development-only version
The letter a, indicating an alpha release
The letter b, indicating a beta release
No letter at all, indicating a final production release
In addition, the letters d, a, and
+b may be followed by another integer, indicating a version
within the release.
For those who like regular expressions:
version_number := ^[0-9]+((\.[0-9]+)+((d|a|b|)[0-9]?)?)$ -
So the following is a valid progression for version numbers:
0.9d, 0.9d1, 0.9a1, 0.9b1, 0.9b2, 0.9, 1.0, 1.0.1, 1.1b1, -1.1
To delete a given version of a package, use the -apm_package_version.delete procedure:
+
So the following is a valid progression for version numbers:
0.9d, 0.9d1, 0.9a1, 0.9b1, 0.9b2, 0.9, 1.0, 1.0.1, 1.1b1, +1.1
To delete a given version of a package, use the
+apm_package_version.delete procedure:
procedure delete (
package_id in apm_packages.package_id%TYPE
);
After creating a version, it is possible to edit the information -associated with it using apm_package_version.edit.
+associated with it usingapm_package_version.edit.function edit ( new_version_id in apm_package_versions.version_id%TYPE @@ -244,8 +243,8 @@ );Files associated with a version can be added and removed. The path is -relative to the package-root which is -acs-server-root/packages/package-key.
+relative to the package-root which is +acs-server-root/packages/package-key.-- Add a file to the indicated version. function add_file( file_id in apm_package_files.file_id%TYPE @@ -326,7 +325,7 @@ version_name_two in apm_package_versions.version_name%TYPE ) return integer; -Creating Instances of a Package
Once a package is registered in the system, it is possible to create +
Creating Instances of a Package
Once a package is registered in the system, it is possible to create instances of it. Each instance can maintain its own content and parameters.
@@ -381,8 +380,8 @@ show errors -Specifying Configuration Parameters for each Instance
A parameter is a setting that can be changed on a package instance basis. -Parameters are registered on each package_key, and the values +
Specifying Configuration Parameters for each Instance
A parameter is a setting that can be changed on a package instance basis.
+Parameters are registered on each package_key, and the values
are associated with each instance. Parameters can have default values and can
be of type 'string' or 'number.' There is support with this
API for setting a number of minimum and maximum values for each parameter,
@@ -463,65 +462,65 @@
attr_value in apm_parameter_values.attr_value%TYPE
);
-
The central piece of the data model is the apm_package_types
table where each package is registered. When a new application or service is
installed on an OpenACS instance, a corresponding row in this table is inserted
with information about the type of package, e.g. if the forum package is installed on your OpenACS server, a row
-in apm_package_types will be created, noting that it's an
-application package type.
The apm_packages table is used to contain information about
+in apm_package_types will be created, noting that it's an
+application package type.
The apm_packages table is used to contain information about
the instances of packages currently created in the system. The
-package_key column references the apm_package_types
+package_key column references the apm_package_types
table to ensure that no package instance can be created for a type that does
-not exist.
The apm_package_versions table contains information specific +not exist.
The apm_package_versions table contains information specific
to a particular version of a package. Several tables reference this one to
-provide further information about the particular version:
apm_package_owners +provide further information about the particular version:
apm_package_owners
Stores information about the owners of a particular version of a package.
-
apm_package_files +
apm_package_files
Stores information about the files that are part of a version.
-
apm_package_dependencies +
apm_package_dependencies
Stores information about what interfaces the package provides and
-requires.
Parameter information is maintained through two tables:
apm_parameters +requires.
Parameter information is maintained through two tables:
apm_parameters
This table contains the definition of each of the parameters for a package.
-
apm_parameter_values +
apm_parameter_values
This table holds all of the values of parameters for specific package
instances.
A number of views are available for obtaining information about packages -registered in the APM.
apm_package_version_info +registered in the APM.
apm_package_version_info
Provides information about all of the versions in the system with
-information available from the apm_package_types table.
+information available from the apm_package_types table.
-
apm_enabled_package_versions +
apm_enabled_package_versions
A view (subset) of the above table with only enabled versions.
-
apm_file_info - Provides a public interface for querying file information.
The APM's user interface is part of the +
apm_file_info
+ Provides a public interface for querying file information.
The APM's user interface is part of the OpenACS Administration Service. The UI is the primary point of contact with APM by developers and administrators. It is part of OpenACS Administration, because only the site-wide administrator should be able to access it. Thus in order to develop a package, the developer must be granted -site-wide administration.
APM has two parameters for configuring how it interacts with the UNIX +site-wide administration.
APM has two parameters for configuring how it interacts with the UNIX filesystem, accessible via the Site Map admin page. These parameters need not be changed under most circumstances, but may -need to be tweaked for Windows compatibility.
GzipExecutableDirectory - This directory points to where the gunzip program can be found -for uncompressing gzip archives. This is needed for the -installation of .apm files which are simply gziped -tarballs. Default is /usr/local/bin +need to be tweaked for Windows compatibility.
GzipExecutableDirectory
+ This directory points to where the gunzip program can be found
+for uncompressing gzip archives. This is needed for the
+installation of .apm files which are simply gziped
+tarballs. Default is /usr/local/bin
-
InfoFilePermissionsMode +
InfoFilePermissionsMode This sets the default UNIX permissions used when creating files using the -APM. Default is 775.
APM has been in production since OpenACS 3.3, and as of version 4.0 offers a stable set of features. One major feature planned is integration with the OpenACS Package Repository for automatic dependency satisfaction. When a user tries to install a package that depends on other packages, the APM will contact the @@ -539,6 +538,6 @@ repositories worldwide.
Another anticipated change is to split the APM UI into separate systems for authoring, maintaining, and installing packages. The current UI presents all of this functionality in one interface and it can be confusing from a -usability perspective.
System creator: Bryan Quinn, Jon Salz, Michael Yoon, Lars Pind, Todd +usability perspective.
System creator: Bryan Quinn, Jon Salz, Michael Yoon, Lars Pind, Todd Nightingale.
System owner: Bryan Quinn
Documentation author: Bryan Quinn, building from earlier versions by Jon -Salz, Michael Yoon, and Lars Pind.