Rule based cache processing in application delivery controller for load balancing

• US 10,560,543 B2
• Filed: 03/26/2015
• Issued: 02/11/2020
• Est. Priority Date: 03/26/2015
• Status: Active Grant

• Current Assignee: Fortinet Inc.
• Original Assignee: Fortinet Inc.
• Inventors: Katsev, Sergey
• Primary Examiner(s): Survillo, Oleg
• Assistant Examiner(s): Cadorna, Christopher P
• Application Number:
  US14/669,367
• Publication Number:
  US 20160285992A1
• Time in Patent Office: 1,783 Days
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1014 based on the content of a request
• CPC Class Codes: H04L 67/535 Tracking the activity of the user network monitoring arrangements H04L43/00; recording of computer activity G06F11/34
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data

Abstract

Methods and systems for improving performance of an HTTP cache are provided. According to one embodiment, an HTTP request is received by an ADC for a resource associated with a server on behalf of which the ADC is performing load balancing. The ADC determines based on a local HTTP cache whether it can service the request. The request is parsed to identify a header. The existence or non-existence of locally cached content matching the request is identified by comparing portions of the identified header with corresponding portions of header information of cached content based on a vary rule defining when two headers are meaningfully different. Therefore, the identified header need not exactly match an entirety of the cached information for a cache hit to be found. Responsive to a cache hit, the ADC responds to the request with an HTTP response containing the identified locally cached content.

Claims

1. A method comprising:

providing a vary rule for execution by a cache hit determination module of an Application Delivery Controller (ADC), wherein the vary rule is generated by the ADC or configured by an administrator of the ADC, wherein the vary rule specifies a Hypertext Transfer Protocol (HTTP) header by name and specifies a rule to be applied to the specified HTTP header in connection with determining whether a value contained within the specified HTTP header of an HTTP request at least partially matches the specified HTTP header of locally cached content within an HTTP cache of the ADC;

receiving, by the ADC an HTTP request from a client device for a resource associated with at least one of a plurality of servers on behalf of which the ADC is performing load balancing;

determining, by the ADC, with reference to the HTTP cache whether the HTTP request can be serviced by the ADC by;

parsing, by the ADC, the HTTP request to identify the specified HTTP header contained therein; and

identifying existence or non-existence of locally cached content at least partially matching the HTTP request by comparing a value of the identified header with a value of the specified HTTP header within a plurality of HTTP headers of content cached within the HTTP cache based on the rule specified in the vary rule, wherein the identified header comprises a cookie header, wherein the vary rule is configured to define conditions under which the cookie header at least partially matches a cached cookie header stored in the HTTP cache, and wherein the cookie header contains an identifier of a server of the plurality of servers that previously processed at least one HTTP request from the client device; and

when a result of said determining indicates the HTTP request can be serviced by the ADC, then responding to the HTTP request, by the ADC, with an HTTP response containing the identified locally cached content.

2. The method of claim 1, further comprising when the result indicates the HTTP request cannot be serviced by the ADC, then selecting a server of the plurality of servers to service the HTTP request.

3. The method of claim 1, wherein the HTTP header specified by the vary rule is a Vary header.

4. The method of claim 1, wherein the rule specified by the vary rule is in a form of a regular expression.

5. The method of claim 1, wherein the result is based on one or more of information regarding a server of the plurality of servers that processed prior HTTP requests by the client device and field values of one or more vary fields that the server defined in connection with responding to the prior HTTP requests.

6. The method of claim 1, further comprising generating, by the ADC, the vary rule responsive to receipt by the ADC of an HTTP response from one of the plurality of servers containing an HTTP header identified within a policy defined by the administrator of the ADC.

7. The method of claim 1, further comprising automatically generating, by the ADC, the vary rule based on semantic knowledge of the ADC regarding an HTTP stream at issue.

8. The method of claim 1, wherein the HTTP header specified by the vary rule is a user-agent header.

9. The method of claim 1, wherein the HTTP header specified by the vary rule is a cookie header.

10. A non-transitory computer-readable storage medium embodying a set of instructions, which when executed by one or more processors of an Application Delivery Controller (ADC), causes the one or more processors to perform a method comprising:

providing a vary rule for execution by a cache hit determination module of the ADC, wherein the vary rule generated by the ADC or configured by an administrator of the ADC, wherein the vary rule specifies a Hypertext Transfer Protocol (HTTP) header by name and specifies a rule to be applied to the specified HTTP header in connection with determining whether a value contained within the specified HTTP header of an HTTP request at least partially matches the specified HTTP header of locally cached content within an HTTP cache of the ADC;

receiving an HTTP request from a client device for a resource associated with at least one of a plurality of servers on behalf of which the ADC is performing load balancing;

determining with reference to the HTTP cache whether the HTTP request can be serviced by the ADC by;

parsing the HTTP request to identify the specified HTTP header contained therein; and

identifying existence or non-existence of locally cached content at least partially matching the HTTP request by comparing a value of the identified header with a value of the specified HTTP header within a plurality of HTTP headers of content cached within the HTTP cache based on the rule specified in the vary rule, wherein the identified header comprises a cookie header, wherein the vary rule is configured to define conditions under which the cookie header at least partially matches a cached cookie header stored in the HTTP cache, and wherein the cookie header contains an identifier of a server of the plurality of servers that previously processed at least one HTTP request from the client device; and

when a result of said determining is affirmative, then responding to the HTTP request with an HTTP response containing the identified locally cached content.

11. The non-transitory computer-readable storage medium of claim 10, further comprising when the result is negative, then selecting a server of the plurality of servers to service the HTTP request.

12. The non-transitory computer-readable storage medium of claim 10, wherein the HTTP header specified by the vary rule is a Vary header.

13. The non-transitory computer-readable storage medium of claim 10, wherein the rule specified by the vary rule is in a form of a regular expression.

14. The non-transitory computer-readable storage medium of claim 10, wherein the result is based on one or more of information regarding a server of the plurality of servers that processed prior HTTP requests by the client device and field values of one or more vary fields that the server defined in connection with responding to the prior HTTP requests.

15. The non-transitory computer-readable storage medium of claim 10, wherein the method further comprises generating the vary rule responsive to receipt by the ADC of an HTTP response from one of the plurality of servers containing an HTTP header identified within a policy defined by the administrator of the ADC.

16. The non-transitory computer-readable storage medium of claim 10, wherein the method further comprises automatically generating the vary rule based on semantic knowledge of the ADC regarding an HTTP stream at issue.

17. The non-transitory computer-readable storage medium of claim 10, wherein the HTTP header specified by the vary rule is a user-agent header.

18. The non-transitory computer-readable storage medium of claim 10, wherein the HTTP header specified by the vary rule is a cookie header.