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Availability State HTTP Servlet Extension

The Availability State HTTP Servlet Extension may be used to obtain a coarse availability state for the Data Governance Server.

The servlet may be invoked with an HTTP HEAD, GET or POST request without any parameters. The HTTP status code of the response is enough for the caller to determine whether the server considers itself to be AVAILABLE, DEGRADED, or UNAVAILABLE. The status code to use for each of these states is configurable.

The response to GET and POST requests may optionally include a body. If it should include a body, then it will be a JSON object (with a Content-Type of application/json) containing the following fields:

↓Parent Component
↓Properties
↓dsconfig Usage

Parent Component

The Availability State HTTP Servlet Extension component inherits from the HTTP Servlet Extension

Properties

The properties supported by this managed object are as follows:


Basic Properties: Advanced Properties:
↓ description  None
↓ cross-origin-policy
↓ response-header
↓ correlation-id-response-header
↓ base-context-path
↓ available-status-code
↓ degraded-status-code
↓ unavailable-status-code
↓ include-response-body

Basic Properties

description

Description
A description for this HTTP Servlet Extension
Default Value
None
Allowed Values
A string
Multi-Valued
No
Required
No
Admin Action Required
None. Modification requires no further action

cross-origin-policy

Description
The cross-origin request policy to use for the HTTP Servlet Extension. A cross-origin policy is a group of attributes defining the level of cross-origin request supported by the HTTP Servlet Extension.
Default Value
No cross-origin policy is defined and no CORS headers are recognized or returned.
Allowed Values
The DN of any HTTP Servlet Cross Origin Policy.
Multi-Valued
No
Required
No
Admin Action Required
None. Modification requires no further action

response-header

Description
Specifies HTTP header fields and values added to response headers for all requests. Values specified here must specify both the header field name and the value in conformance with RFC 2616. Fields may only be specified once; multiple values for the same header should be comma-separated. See RFC 7231 for a standard set of field names.
Any response headers configured for this HTTP Servlet Extension will be combined with response headers configured on the corresponding Connection Handler. In the case of duplicates, the headers configured on this HTTP Servlet Extension will be used instead of the headers configured on the Connection Handler.
Default Value
None
Allowed Values
Colon-separated header field name and value
Multi-Valued
Yes
Required
No
Admin Action Required
HTTP Connection Handlers hosting this HTTP Servlet Extension must be disabled and then re-enabled, or the server restarted, in order for this change to take effect.

correlation-id-response-header

Description
Specifies the name of the HTTP response header that will contain a correlation ID value. Example values are "Correlation-Id", "X-Amzn-Trace-Id", and "X-Request-Id". This property can be used to specify a custom response header name for correlation IDs. The value specified here will override the correlation-id-response-header property of the HTTP Connection Handler hosting this HTTP Servlet Extension.

If the use-correlation-id-header property of the HTTP Connection Handler hosting this HTTP Servlet Extension is not enabled, then this property will be ignored.

Default Value
The correlation-id-response-header property of the HTTP Connection Handler hosting this HTTP Servlet Extension will be used.
Allowed Values
A string
Multi-Valued
No
Required
No
Admin Action Required
None. Modification requires no further action

base-context-path

Description
Specifies the base context path that HTTP clients should use to access this servlet. The value must start with a forward slash and must represent a valid HTTP context path.
Default Value
None
Allowed Values
The value must start with a forward slash and must represent a valid HTTP context path.
Multi-Valued
No
Required
Yes
Admin Action Required
The Availability State HTTP Servlet Extension must be disabled and re-enabled for changes to this setting to take effect. In order for this modification to take effect, the component must be restarted, either by disabling and re-enabling it, or by restarting the server

available-status-code

Description
Specifies the HTTP status code that the servlet should return if the server considers itself to be available.
Default Value
None
Allowed Values
An integer value. Lower limit is 100. Upper limit is 599 .
Multi-Valued
No
Required
Yes
Admin Action Required
None. Modification requires no further action

degraded-status-code

Description
Specifies the HTTP status code that the servlet should return if the server considers itself to be degraded.
Default Value
None
Allowed Values
An integer value. Lower limit is 100. Upper limit is 599 .
Multi-Valued
No
Required
Yes
Admin Action Required
None. Modification requires no further action

unavailable-status-code

Description
Specifies the HTTP status code that the servlet should return if the server considers itself to be unavailable.
Default Value
None
Allowed Values
An integer value. Lower limit is 100. Upper limit is 599 .
Multi-Valued
No
Required
Yes
Admin Action Required
None. Modification requires no further action

include-response-body

Description
Indicates whether the response should include a body that is a JSON object. If a response body should be returned, it will be a JSON object with an "availability-state" field whose value is the string "AVAILABLE", "DEGRADED", or "UNAVAILABLE".
Default Value
true
Allowed Values
true
false
Multi-Valued
No
Required
No
Admin Action Required
None. Modification requires no further action


dsconfig Usage

To list the configured HTTP Servlet Extensions:

dsconfig list-http-servlet-extensions
     [--property {propertyName}] ...

To view the configuration for an existing HTTP Servlet Extension:

dsconfig get-http-servlet-extension-prop
     --extension-name {name}
     [--tab-delimited]
     [--script-friendly]
     [--property {propertyName}] ...

To update the configuration for an existing HTTP Servlet Extension:

dsconfig set-http-servlet-extension-prop
     --extension-name {name}
     (--set|--add|--remove) {propertyName}:{propertyValue}
     [(--set|--add|--remove) {propertyName}:{propertyValue}] ...

To create a new Availability State HTTP Servlet Extension:

dsconfig create-http-servlet-extension
     --extension-name {name}
     --type availability-state
     --set base-context-path:{propertyValue}
     --set available-status-code:{propertyValue}
     --set degraded-status-code:{propertyValue}
     --set unavailable-status-code:{propertyValue}
     [--set {propertyName}:{propertyValue}] ...

To delete an existing HTTP Servlet Extension:

dsconfig delete-http-servlet-extension
     --extension-name {name}