OSGi Configuration Settings

OSGi is a fundamental element in the technology stack of AEM. It is used to control the composite bundles of AEM and their configuration.

OSGi “provides the standardized primitives that allow applications to be constructed from small, reusable and collaborative components. These components can be composed into an application and deployed”.

This allows easy management of bundles as they can be stopped, installed, started individually. The interdependencies are handled automatically. Each OSGi Component (see the OSGi Specification) is contained in one of the various bundles. When working with AEM there are several methods of managing the configuration settings for such bundles; see Configuring OSGi for more details and the recommended practices.

The following OSGi configuration settings (listed according to bundle) are relevant to project implementation. Not all the listed settings need adjusting, some are mentioned to help you understand how AEM operates.

AEM Replication Event Listener Configure:

• The Run Modes, in which replication events will be distributed to listeners. For example, if defined as author, then this is the system that will “initiate” the replication.

• The run mode publish needs to be added if the project code processes replication events (reverse replication) in a publish environment. For example, when the dispatcher is used to flush from the publish environment or when standard replication to other publish instances occurs.

AEM Repository change listener Configure:

• The Paths, locations to listen for repository events ready for distribution.

CRX Sling Client Repository Configure access to the underlying content repository.

• The Admin Password should be changed after installation to ensure the security of your instance.
• Other changes should not be necessary and care must be taken as they can affect access to the repository.

Apache Felix OSGi Management Console Configure:

• Plugins, the main navigation items (console plugins) to be available in the Apache Felix Web Management Console as top level menu items. Disable any you do not need as each requires space and resources.

Apache Sling Customizable Request Data Logger Configure:

• Logger Name and Log Format to configure the location and format of request and access logging (default: request.log). This log file is essential when analyzing performance or debugging functionality related to the web chain.
  This is paired with the Apache Sling Request Logger.

For further information see AEM Logging and Sling Logging.

Apache Sling Eventing Thread Pool Configure:

• Min Pool Size and Max Pool Size, the size of the pool used to hold event threads.

• Queue Size, the maximum size of the thread queue if the pool is exhausted.
  The recommended value is -1 as this sets the queue to unlimited; if a limit is set then losses might occur when it is exceeded.

• Changing these settings can help performance in scenarios with a high number of events; for example, heavy AEM DAM or Workflow usage.

• Values specific to your scenario should be established using tests.

• These settings can affect the performance of your instance, so do not change them without reason and due consideration.

Apache Sling GET Servlet Configure some aspects of rendering:

• Auto Index to enable/disable directory rendering for browsing.
• Enable (or disable) default renditions, such as HTML, Plain Text, JSON or XML.
  You should not disable JSON.

Apache Sling Java Script Handler Configure settings for the compilation of .java files as scripts (servlets).

Certain settings can affect performance, these should be disabled where possible, in particular for a production instance.

• Source VM and Target VM, define the JDK version as that used as the runtime JVM

• for production instances:

  • disable Generate Debug Info

Apache Sling JCR Installer These parameters probably do not need configuration, but can be useful to know when developing or debugging. For example the installation folder(s) can be useful for checking in/out or creating a package.

• Installation folders name regexp and Max hierarchy depth of install folders - specify where, and to which depth, repository folders are searched for resources to be installed. When a wildcard is used (as in .*/install) all appropriate matches will be searched, for example, /libs/sling/install and /libs/cq/core/install.

• Search Path, list of paths that jcrinstall searches for resources to be installed, together with a number indicating the weighting factor for that path.

Apache Sling Job Event Handler Configure parameters that manage job scheduling:

• Retry interval, Maximum Retries, Maximum Parallel Jobs, Acknowledge Wait Time, amongst others.

• Changing these settings can improve performance in scenarios with a high number of jobs; for example, heavy usage of AEM DAM and Workflows.

• Values specific to your scenario should be established using tests.

• Do not change these settings without reason, only change after due consideration.

Apache Sling JSP Script Handler Configure performance relevant settings for the JSP script handler. To improve performance you should disable as much as possible.

In particular for production instances:

• disable Generate Debug Info
• disable Keep Generated Java
• disable Mapped Content
• disable Display Source Fragments

Apache Sling Logging Configuration Configure:

• Log Level and Log File, to define the location and log level of the central logging configuration (error.log). The level can be set to one of DEBUG, INFO, WARN, ERROR and FATAL.

• Number of Log Files and Log File Threshold to define the size and version rotation of the log file.

• Message Pattern defines the format of the log messages.

For further information see AEM Logging and Sling Logging.

Apache Sling Logging Logger Configuration (Factory Configuration) Configure:

• Log Level, Log File and Message Format to define details of the log file and messages.

• Logger to define the category; for example, only log for com.day.cq.

• By using Factory Configurations, any number of additional configurations can be added to cater with the various log levels and categories needed.

• Such configurations are helpful during development; for example, to log TRACE messages for a specific service in a specific log file.

• Such configurations are helpful in a production environment; for example, to have messages about a specific service logged to an individual log file for easier monitoring.

For further information see AEM Logging and Sling Logging.

Apache Sling Logging Writer Configuration (Factory Configuration) Configure:

• Log File to define the existence of a log file.

• Number of Log Files to define the version rotation.

• The writer can be used by a Apache Sling Logging Logger Configuration configuration.

• Such configurations are helpful during development; for example, to log TRACE messages for a specific service in a specific log file.

• Such configurations are helpful in a production environment; for example, to have messages about a specific service logged to an individual log file for easier monitoring.

For further information see AEM Logging and Sling Logging.

Apache Sling Main Servlet Configure:

• Number of Calls per Request and Recursion Depth to protect your system against infinite recursion and excessive script calls.

Apache Sling MIME Type Service Configure:

• MIME Types to add those required by your project to the system. This allows a GET request on a file to set the correct content-type header for linking the file type and application.

Apache Sling Referrer Filter To address known security issues with Cross-Site Request Forgery (CSRF) in CRX WebDAV and Apache Sling you need to configure the Referrer filter.

The referrer filter service is an OSGi service that allows you to configure:

• which http methods should be filtered
• whether an empty referrer header is allowed
• and a list of servers to be allowed in addition to the server host.

See the Security Checklist - Issues with Cross-Site Request Forgery for further details.

Apache Sling Request Logger Configure:

• various parameters to define how requests are logged.

• Enable Request Log, to enable or disable.

• Enable Access Log, to enable or disable.

This is paired with the Apache Sling Customizable Request Data Logger.

For further information see AEM Logging and Sling Logging.

Apache Sling Resource Resolver Factory Configure central aspects of Sling resource resolution:

• Resource Search Path(s), add any project specific paths (but do not remove /libs or /apps).

• Virtual URLs to define your vanity URL mappings.

• URL Mappings to define any aliases; for example from /content to /.

• Mapping Location, the mapper configuration externalized in /etc/map.

• Use your local installation (for example, use https://localhost:4502/system/console/jcrresolver) to determine which Resource Resolver is active.

For further information see: https://cwiki.apache.org/confluence/display/SLING/Flexible+Resource+Resolution.

Apache Sling Servlet/Script Resolver and Error Handler The Sling Servlet and Script Resolver has multiple tasks:

1. It is used as the ServletResolver to select the Servlet or Script to call to handle the request.

2. It acts as the SlingScriptResolver.

3. It manages error handling by implementing the ErrorHandler interface using the same algorithm to select error handling servlets and scripts as is used to resolve request processing servlets and scripts.

Various parameters can be set, including:

• Execution Paths lists the paths to search for executable scripts; by configuring specific paths you can limit which scripts can be executed. If no path is configured then the default is used ( / = root), this allows the execution of all scripts.
  If a configured path value ends with a slash, the whole sub tree is searched. Without such a trailing slash the script will only be executed if it is an exact match.

• Script User - this optional property can specify the repository user account used for reading the scripts. If no account is specified the admin user is used by default.

• Default Extensions The list of extensions for which the default behavior will be used. This means that the last path segment of the resource type can be used as the script name.

Apache HTTP Components Proxy Configuration Proxy configuration for all code using the Apache HTTP client, used when a HTTP is made; for example upon replication.

When creating a new configuration, do not make changes to the factory configuration but instead create a new factory configuration for this component using the configuration manager available here: https://localhost:4502/system/console/configMgr/. The proxy configuration is available in org.apache.http.proxyconfigurator.

Day CQ Antispam Configure the anti-spam service (Akismet) used. This requires you to register the:

• Provider
• API key
• Registered URL

Adobe Granite HTML Library Manager Configure this to control the handling of client libraries (css or js); including, for example, how the underlying structure is seen.

• For production instances:

  • enable Minify (to remove CRLF and whitespace characters).
  • enable Gzip (to allow files to be gzipped and accessed with one request).
  • disable Debug
  • disable Timing

• For JS development (especially when firebugging/debugging):

  • disable Minify
  • enable Debug to separate the files for debugging and use with firebug.
  • enable Timing in the case of interest in timing.
  • enable Debug console to see JS console log messages.

Day CQ HTTP Header Authentication Handler System wide settings for the basic authentication method of the HTTP request.

When using closed user groups you can configure (amongst others):

• HTTP Realm
• The Default Login Page

Day CQ Link Checker Service Check and if necessary configure:

• Scheduler Period to define the interval at which external links are to be automatically checked.

• Check Bad Link Tolerance Interval for the period after which an unsuccessful external link is considered bad.

• Link Check Override Patterns, to define any paths to be excluded from link checking.

Day CQ Link Checker Task Configure settings for a single link checker task (a task which checks an external link):

• Check the intervals defined in Good Link Test Interval and Bad Link Test Interval

• The various parameters related to proxies for internet access and NTLM that are needed for external access when checking a link.

Day CQ Mail Service Configure hostname and access details for the mail server. Please refer to the Configuring the Mail Service section.

Day CQ MCM Newsletter Configure the various settings used with the newsletter.

Day CQ Root Mapping Configure:

• Target Path to define where a request to " /" will be redirected to.

There are two UIs available in AEM:

• the touch-enabled UI is the standard UI
• and the deprecated classic UI is still fully operational

Using AEM Root Mapping you can configure the UI that you want to have as the default for your instance:

• To have the touch-enabled UI as the default UI the Target Path should point to:

     /projects.html
  

• To have the classic UI as the default UI the Target Path should point to:

     /welcome.html
  

Adobe Granite SSO Authentication Handler Configure Single Sign On (SSO) details; these are often needed in enterprise author setups, often in conjunction with LDAP.

Various configuration properties are available:

• Path
  Path for which this authentication handler is active. If this parameter is left empty the authentication handler is disabled. For example, the path / causes the authentication handler to be used for the entire repository.

• Service Ranking
  OSGi Framework Service Ranking value is used to indicate the order used for calling this service. This is an int value where higher values designate higher precedence.
  Default value is 0.

• Header Names
  The name(s) of headers that might contain a user ID.

• Cookie Names
  The name(s) of cookies that might contain a user ID.

• Parameter Names
  The name(s) of request parameters that might provide the user ID.

• User Map
  For selected users, the user name extracted from the HTTP request can be replaced with a different one in the credentials object. The mapping is defined here. If the user name admin appears on either side of the map, the mapping will be ignored. Please be aware that the character “=” has to be escaped with a leading “”.

• Format
  Indicates the format in which the user ID is provided. Use:

  • Basic if the user ID is encoded in the HTTP Basic Authentication format
  • AsIs if the user ID is provided in plain text or any regular expression applied value should be used as is or any regular expression

Day CQ WCM Debug Filter This is useful when developing as it allows the use of suffixes such as ?debug=layout when accessing a page. For example, https://localhost:4502/cf#/content/geometrixx/en/support.html?debug=layout will provide layout information that may be of interest to the developer.

• Disable this on production instances to ensure performance and security.

Day CQ WCM Filter Configure:

• **WCM Mode **to define the default mode.

• On an author instance this might be edit, disable,preview or analytics.
  The other modes can be accessed from the sidekick, or the suffix ?wcmmode=disabled can be used to emulate a production environment.

• On a publish instance this must be set to disabled to ensure that no other mode is accessible.

Day CQ WCM Link Checker Configurator Configure:

• List of rewrite configurations to specify a list of locations for content-based linkchecker configurations. The configurations can be based on run mode; this is important to distinguish between author and publish environments, as linkchecker settings may differ.

Day CQ WCM Page Manager Factory Configure:

• Page Subtree Activation Check for a user (without replication permissions) to delete or move pages (even if the pages are not activated).

Day CQ WCM Page Processor Configure:

• Paths, a list of locations where the system listens for page modifications before triggering a jcr:Event.

Adobe Page Impressions Tracker For an author instance configure:

• sling.auth.requirements: set the value of this property to -/libs/wcm/stats/tracker

Day CQ WCM Page Statistics For a publish instance configure:

• URL to send data to configure the URL used to track page statistics (is vital if a tracker request goes through the dispatcher); for example, the default is https://localhost:4502/libs/wcm/stats/tracker.

• Tracking script enabled to enable ( true) or disable ( false) the inclusion of the tracking script on the pages. The default value is false.

Day CQ WCM Version Manager Control if, and how, versions are managed in your system:

• Create Version on Activation, enabled in a standard installation

• Enable Purging

• Purge Paths, the paths that a search action will search

• Implicit Versioning Paths, the paths where implicit versioning is active.

• Max Version Age, the maximum age (in days) of a version

• Max Number Versions, the maximum number of versions to keep

See Version Purging for more information.

Day CQ Workflow Email Notification Service Configure the email settings for notifications sent by a workflow.

CQ Rewriter HTML Parser Factory

Controls the HTML Parser for the CQ rewriter.

• Additional Tags to Process - You can add or remove HTML tags to be processed by the parser. By default, the following tags are processed: A,IMG,AREA,FORM,BASE,LINK,SCRIPT,BODY,HEAD.
• Preserve Camel Case - By default, the HTML parser converts attributes in camel case (e.g. eBay) to lower case (e.g. ebay). You can turn this off to preserve the camel case attributes. This is useful when using frontend frameworks such as Angular 2.

Day Commons JDBC Connections Pool Configure access to an external database being used as a source for content.

This is a Factory Configuration, so multiple instances can be configured.

CDN Rewriter Communication between AEM and a CDN must be ensured so that assets/binaries are delivered to end user in a secure way. This involves two tasks:

• Accessing the resource from AEM via the CDN the very first time (or after it expired in cache).
• Accessing the resource cached in CDN securely since once the resource is cached in CDN, the request won’t go to AEM and all the users who have access to that resource on should be served from CDN.

AEM provides a rewriter for rewriting internal assets URLs to external CDN URLs. It rewrites links to be passed on to the CDN including a JWS signature and expire time to allow the asset to be accessed securely. This feature is to be used on author instances.

The overall flow is as follows:

1. User authenticates with AEM and requests a page with assets.

2. Requested page contains an asset similar to /content/dam/geometrixx-media/articles/paladin_trailer.jpg/jcr:content/renditions/cq5dam.thumbnail.319.319.png

3. Rewriter transforms the link to a CDN URL containing a JWS Signature:
   CDN_domain/content/dam/geometrixx-media/articles/paladin_trailer.jpg/_jcr_content/renditions/cq5dam.thumbnail.319.319.png?cdn_sign=JWS_SIGNATURE

4. User’s browser then forwards the asset request to CDN server

5. CDN should be configured to forward the request to AEM along with the cdn_sign parameter.

6. An Authentication Handler validates the cdn_sign parameter and returns the asset to CDN which is then delivered to user

The flow between the user’s browser, the CDN, and AEM can be visualized as follows.

CDNConfigServiceImpl Provides CDN configurations

The CDN rewriting feature can be enabled by providing CDN distribution domain name in the configuration for com.adobe.cq.cdn.rewriter.impl.CDNConfigServiceImpl.

The service also contains other configuration options like enabling/disabling CDN rewriting, path prefixes for which CDN rewriting is performed, TTL values, and protocol (HTTP or HTTPS).

CDNRewriter A rewriter for rewriting internal image URLs to CDN URLs

The Tag Attributes value in com.adobe.cq.cdn.rewriter.impl.CDNRewriter can be defined so that only selective image links are rewritten.

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