# US 2024/0202053 A1 · Performing api services using zone-based topics within a pub/sub messaging infrastructure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0202053 A1 - Document ID: US20240202053A1 - Status: Published application - Kind: A1 - Application number: 18/068,738 - Filed: 2022-12-20 - Published: 2024-06-20 - Earliest claimed: 2022-12-20 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Rong Nickle Chang; Kumar Bhaskaran - Web page: https://patentgrep.com/patent/US20240202053A1 ## CPC - G06F 9/547: {Remote procedure calls [RPC]; Web services} - H04L 41/5058: {Service discovery by the service manager} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method, computer program product, and computer system for performing an Application Programming Interface (API) service using zone-based topics within a publish/subscribe (pub/sub) messaging infrastructure. An API service request sent by a client entity is received and specifies an API service to be fulfilled. A selection of an API service endpoint configured to execute the API service is received. Messages are posted to respective pub/sub zone-based topics, resulting in selection of workers subscribed to the respective zone-based topics. Each zone-based topic includes tasks to be performed in a specified one or more zones. For each zone-based topic, the tasks of the zone-based topic are implemented by executing the worker selected for the zone-based topic. The tasks of the zone-based topics include invoking the API service endpoint for the requested API service and making a fulfillment result of the API service available to the client entity. ## Claims ### Claim 1 A method for performing an Application Programming Interface (API) service using zone-based topics within a publish/subscribe (pub/sub) messaging infrastructure, said method comprising: receiving, by one or more processors, an API service request sent by a client entity, said API service request specifying an API service to be fulfilled; receiving, by the one or more processors, a selection of an API service endpoint configured to execute the API service; posting, by the one or more processors, messages to respective pub/sub zone-based topics of a sequence of zone-based topics, resulting in selection, by the one or more processors, of workers who are subscribed to the respective zone-based topics, each zone-based topic comprising one or more tasks to be performed in a specified one or more zones; for each zone-based topic, implementing, by the one or more processors, the one or more tasks of the zone-based topic, said implementing the one or more tasks having been performed by executing the worker selected for the zone-based topic, wherein the tasks of the zone-based topics include invoking the API service endpoint for the API service and making a fulfillment result of the API service available to the client entity. ### Claim 2 (depends on 1) The method of claim 1, wherein for each zone-based topic, the one or more tasks of the zone-based topic include a task to update a fulfillment status indicator denoting an extent to which the API service request has been fulfilled. ### Claim 3 (depends on 1) The method of claim 1, said method further comprising: receiving, by the one or more processors, a selection of an API service invocation model supported by the selected API service endpoint, wherein said implementing the one or more tasks of the zone-based topic is in accordance with the selected API service invocation model, and wherein said invoking the API service endpoint is in accordance with the selected API service invocation model, and wherein the API service invocation model is either a synchronous invocation model or an asynchronous invocation model, with respect to interactions between the API service endpoint and the workers. ### Claim 4 (depends on 3) The method of claim 3, wherein the API service invocation model is the synchronous invocation model. ### Claim 5 (depends on 3) The method of claim 3, wherein the API service invocation model is the asynchronous invocation model. ### Claim 6 (depends on 1) The method of claim 1, wherein the sequence of zone-based topics is denoted as T1, T2, . . . , TM, wherein M is at least 3, wherein said posting the message to the zone-based topic Tm is performed by executing the worker selected for the zone-based topic Tm-1 (m=2, . . . , and M). ### Claim 7 (depends on 6) The method of claim 6, wherein a worker HEAD receives the API service request sent by the client entity, and wherein said posting the message to the zone-based topic T1 is performed by executing the worker HEAD. ### Claim 8 (depends on 1) The method of claim 1, wherein each topic is zone-based with respect to N zones, and wherein N is at least 2. ### Claim 9 (depends on 8) The method of claim 8, wherein N is constant over the zone-based topics. ### Claim 10 (depends on 8) The method of claim 8, wherein N is not constant over the zone-based topics and differs for at least two of the zone-based topics. ### Claim 11 (depends on 8) The method of claim 8, said method further comprising: in response to a zone related problem pertaining to executing one worker selected for one zone-based topic wherein the one worker is executed in one zone of the N zones, replacing, by the one or more processors, the one worker by another worker subscribed to the one zone-based topic and is executed in another zone of the N zones. ### Claim 12 (depends on 1) The method of claim 1, wherein fulfillment of the API service is asynchronous to the client entity. ### Claim 13 (depends on 1) The method of claim 1, wherein the one or more processors are general purpose processors. ### Claim 14 (depends on 1) The method of claim 1, wherein the one or more processors comprise an application specific integrated circuit (ASIC), and wherein electrical circuitry within the ASIC is hard wired to perform the method. ### Claim 15 A computer program product, comprising one or more computer readable hardware storage devices having computer readable program code stored therein, said program code containing instructions executable by one or more processors of a computer system to implement a method for performing an Application Programming Interface (API) service using zone-based topics within a publish/subscribe (pub/sub) messaging infrastructure said method comprising: receiving, by the one or more processors, an API service request sent by a client entity, said API service request specifying an API service to be fulfilled; receiving, by the one or more processors, a selection of an API service endpoint configured to execute the API service; posting, by the one or more processors, messages to respective pub/sub zone-based topics of a sequence of zone-based topics, resulting in selection, by the one or more processors, of workers who are subscribed to the respective zone-based topics, each zone-based topic comprising one or more tasks to be performed in a specified one or more zones; for each zone-based topic, implementing, by the one or more processors, the one or more tasks of the zone-based topic, said implementing the one or more tasks having been performed by executing the worker selected for the zone-based topic, wherein the tasks of the zone-based topics include invoking the API service endpoint for the API service and making a fulfillment result of the API service available to the client entity. ### Claim 16 (depends on 15) The computer program product of claim 15, wherein for each zone-based topic, the one or more tasks of the zone-based topic include a task to update a fulfillment status indicator denoting an extent to which the API service request has been fulfilled. ### Claim 17 (depends on 15) The computer program product of claim 15, said method further comprising: receiving, by the one or more processors, a selection of an API service invocation model supported by the selected API service endpoint, wherein said implementing the one or more tasks of the zone-based topic is in accordance with the selected API service invocation model, and wherein said invoking the API service endpoint is in accordance with the selected API service invocation model, and wherein the API service invocation model is either a synchronous invocation model or an asynchronous invocation model, with respect to interactions between the API service endpoint and the workers. ### Claim 18 A computer system, comprising one or more processors, one or more memories, and one or more computer readable hardware storage devices, said one or more hardware storage devices containing program code executable by the one or more processors via the one or more memories to implement a method for performing an Application Programming Interface (API) service using zone-based topics within a publish/subscribe (pub/sub) messaging infrastructure, said method comprising: receiving, by the one or more processors, an API service request sent by a client entity, said API service request specifying an API service to be fulfilled; receiving, by the one or more processors, a selection of an API service endpoint configured to execute the API service; posting, by the one or more processors, messages to respective pub/sub zone-based topics of a sequence of zone-based topics, resulting in selection, by the one or more processors, of workers who are subscribed to the respective zone-based topics, each zone-based topic comprising one or more tasks to be performed in a specified one or more zones; for each zone-based topic, implementing, by the one or more processors, the one or more tasks of the zone-based topic, said implementing the one or more tasks having been performed by executing the worker selected for the zone-based topic, wherein the tasks of the zone-based topics include invoking the API service endpoint for the API service and making a fulfillment result of the API service available to the client entity. ### Claim 19 (depends on 18) The computer system of claim 18, wherein for each zone-based topic, the one or more tasks of the zone-based topic include a task to update a fulfillment status indicator denoting an extent to which the API service request has been fulfilled. ### Claim 20 (depends on 18) The computer system of claim 18, said method further comprising: receiving, by the one or more processors, a selection of an API service invocation model supported by the selected API service endpoint, wherein said implementing the one or more tasks of the zone-based topic is in accordance with the selected API service invocation model, and wherein said invoking the API service endpoint is in accordance with the selected API service invocation model, and wherein the API service invocation model is either a synchronous invocation model or an asynchronous invocation model, with respect to interactions between the API service endpoint and the workers.