Remote procedure calling system and method

Abstract

The invention relates to the technical field of virtualization, and discloses a remote procedure calling system and method.The system comprises an interface calling party, an interface service provider and a service registration discovery platform built for a storage database based on distributed key values, and the interface service provider carries out service registration on the service registration discovery platform in advance; the interface calling party generates task data according to the business demand, and issues the task data to the service registration discovery platform; the service registration discovery platform stores the task data; the interface service provider monitors task data of the service registration discovery platform, and updates the task data after calling a corresponding processing method according to the task data; and the interface calling party processes the business demand based on the updated task data. According to the method, the service registration discovery platform is constructed, so that services can communicate with each other without an IP (Internet Protocol) and a port based on a watch mechanism and a task mechanism, and related data is recorded, so that dependence on components is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of virtualization, and in particular to a remote procedure call system and method. Background Art

[0002] At present, distributed systems and microservices are used in more and more systems, and the interface calls between service systems are also very common and frequent. The interface calls between services generally use the HTTP protocol or the RPC (Remote Procedure Call) protocol, and the communication between components within the distributed system will more often choose the RPC protocol. Currently, common RPC frameworks include Google's GRPC and Facebook's Thrift. The registration of such framework services depends on IP (Internet Protocol) and listening ports, and in addition to separate database services, service registration and discovery middleware support is also required, such as Zookeeper, Consul, etc. In addition to increasing resource consumption, this also requires the R&D team to be familiar with the operation and maintenance technologies and working principles of various components. In addition, if it is necessary to record each RPC request and trace the operation, it is generally necessary to add an additional gateway service to persist the request. Summary of the invention

[0003] In view of this, the present invention provides a remote procedure call system and method to solve the problem of multiple call-dependent components and lack of operation request records between distributed systems.

[0004] In a first aspect, the present invention provides a remote procedure call system, the system comprising: an interface caller, an interface service provider and a service registration and discovery platform, wherein the service registration and discovery platform is constructed based on a distributed key-value pair storage database, and the interface service provider pre-registers a service on the service registration and discovery platform;

[0005] The interface caller is used to generate task data for the interface service provider according to business needs and send the task data to the service registration and discovery platform;

[0006] Service registration and discovery platform, used to store task data;

[0007] The interface service provider is used to monitor the task data of the service registration and discovery platform, and update the task data after calling the corresponding processing method according to the task data;

[0008] The interface caller is also used to process business requirements based on the updated task data.

[0009] The remote procedure call system provided by the embodiment of the present invention builds a service registration and discovery platform based on a distributed key-value pair storage database, and pre-registers the interface service provider on the service registration and discovery platform. The interface service provider stores the task data between the interface caller and the interface service provider. The interface caller issues the task data according to the business requirements. The interface service provider monitors the task data and updates the task data after calling the corresponding processing method based on the task data. The interface call is then processed to process the business requirements. By building a service registration and discovery platform, the present invention can enable services to communicate with each other without using IP and ports based on the watch mechanism and the task mechanism, and record relevant data to avoid dependence on components.

[0010] In an optional implementation, the interface caller includes: an application program interface, a resource scheduling service and / or a scheduled task service.

[0011] The present invention can realize the calling of interface service providers by various interface callers.

[0012] In an optional implementation, the interface service provider pre-registers the service on the service registration and discovery platform, including: generating identification information based on the host machine corresponding to the interface service provider; obtaining resource information and configuration information of the host machine collected by the interface service provider, and storing the information; obtaining the interface type, request data structure, and response data structure of the remote procedure call defined by the interface service provider for the host machine.

[0013] The present invention can set a unique identifier for the interface service provider by registering the interface service provider on a service registration and discovery platform, thereby managing the task data between the interface caller and the interface service provider based on the identifier, thereby realizing remote procedure calls between the interface caller and the interface service provider.

[0014] In a second aspect, the present invention provides a remote procedure call method, which is applied to an interface caller, and the method comprises:

[0015] Generate task data for interface service providers based on business needs;

[0016] Send the task data to the service registration and discovery platform and monitor the task data;

[0017] If the task data is updated, the business needs are processed according to the updated task data.

[0018] The remote procedure call method applied to the interface caller provided in the embodiment of the present invention can implement the remote procedure call of the interface service provider by issuing task data on the service registration and discovery platform and monitoring the task data, thereby completing the business process of the system where the interface caller is located.

[0019] In an optional implementation, monitoring the task data includes: if the business demand is an asynchronous task, processing other business demands according to the business process, and monitoring the task data by polling; if the business demand is a synchronous task, monitoring the task data in real time.

[0020] The present invention can achieve different tasks through different monitoring modes and ensure the smooth progress of business processes.

[0021] In a third aspect, the present invention provides a remote procedure call method, which is applied to an interface service provider, and the method comprises:

[0022] Based on the registration information pre-registered on the service registration and discovery platform, monitor the task data of the service registration and discovery platform;

[0023] If task data is monitored, the corresponding processing method is called based on the task data;

[0024] Update the task data according to the processing results.

[0025] The remote procedure call method applied to the interface service provider provided in the embodiment of the present invention can respond to the remote procedure call of the interface caller in a timely manner by monitoring the task data of the service registration and discovery platform, thereby realizing communication between distributed service systems.

[0026] In an optional implementation, calling a corresponding processing method based on task data includes: parsing the task data to determine the interface type of the remote procedure call; and calling a corresponding processing method according to the interface type.

[0027] The present invention can determine the business requirements of the interface caller by parsing the task data and provide corresponding services for the interface caller.

[0028] In a fourth aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the remote procedure call method of the second aspect, the third aspect or any corresponding embodiment thereof by executing the computer instructions.

[0029] In a fifth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the remote procedure call method of the first aspect, the second aspect or any corresponding embodiment thereof.

[0030] In a sixth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the remote procedure call method of the first aspect, the second aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a structural block diagram of a remote procedure call system according to an embodiment of the present invention;

[0033] Figure 2 is a system architecture of a remote procedure call system according to an embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of a registration process of a remote procedure call system according to an embodiment of the present invention;

[0035] Figure 4 is a flowchart of a remote procedure call method according to an embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of a request process of a remote procedure call method according to an embodiment of the present invention;

[0037] Figure 6 is a schematic diagram of a response process of a remote procedure call method according to an embodiment of the present invention;

[0038] Figure 7 is a flowchart of another remote procedure call method according to an embodiment of the present invention;

[0039] Figure 8 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0041] The embodiments of the present invention are applicable to application scenarios in which distributed systems communicate with each other, such as cloud platform management and control systems, and the operation tasks of hosts / network cards, etc. are issued and executed. At present, the service registration of common RPC frameworks depends on IP and listening ports, and in addition to separate database services, service registration and discovery middleware support is also required. In addition to increasing more resource consumption, this also requires the R&D team to be familiar with the operation and maintenance technologies and working principles of various components. However, in the case of miniaturized distributed systems or scenarios where rapid demo (sample) development is required, R&D personnel may not know much about the middleware and other technologies required for various complex distributed systems. They need to focus more on the development and implementation of business logic or rapid verification of prototypes. Moreover, service registration and discovery is generally performed by recording the IP and port information of the service, and then the service provider and the service caller communicate directly point-to-point. In some scenarios with high security requirements, this is prone to point-to-point network problems due to various firewalls or IP rules, thereby affecting the overall system availability. In addition, existing RPC calls are all based on registering the service IP and Port as addressing conditions in the service discovery service; the client and the server access the RPC interface in a point-to-point manner. This approach may require additional service discovery components, and generally does not store each request and response content, and can only be traced back through logs. In addition, in scenarios where requests take a long time, the request will occupy the link for a long time, and the overall QPS / TPS of the service will be limited.

[0042] ETCD is a distributed KV storage database with strong consistency, an important component in cloud native scenarios, and can generally be used for data storage, as well as for service registration and discovery. Therefore, an embodiment of the present invention provides a remote procedure call system, which achieves the effect of remote procedure call between the interface caller and the interface service provider through a service registration and discovery platform built based on ETCD. The relevant terms involved in the embodiments of the present invention are explained as follows:

[0043] RPC: A computer software communication protocol that allows a program on one computer to call a program on another computer just like calling a local program interface. It is mainly used for inter-interface calls between distributed system services. RPC usually uses TCP or UDP as the underlying transport protocol.

[0044] KV (KEY-VALUE) database: The data in the database is stored and indexed in the form of key-value pairs. It is more suitable for data that does not have too many business relationships and generally has better read and write performance than relational databases.

[0045] ETCD: A reliable distributed KV storage database, an important component in cloud native scenarios, often used as a KV database and service registration and discovery.

[0046] JSON (JavaScript Object Notation): A lightweight data exchange format that is commonly used for data exchange between various services. It supports most languages ​​and is easy for humans to understand and read.

[0047] Libvirt: A set of tools for managing various virtualization platforms, supporting languages ​​such as C, Python, Perl, Go, etc., and supporting the management of mainstream virtualization technologies such as KVM (Kernel-based Virtual Machine), QEMU, Xen, VMWare ESX, LXC (Linux Containers), etc.

[0048] QPS / TPS: Qureies Per Second / Transactions Per Second, the number of requests / transactions processed by the system per second.

[0049] According to an embodiment of the present invention, a remote procedure call system embodiment is provided. It should be noted that, as used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0050] In this embodiment, a remote procedure call system is provided, which can be used in a mobile terminal, such as a computer. Figure 1 is a structural block diagram of a remote procedure call system according to an embodiment of the present invention. Figure 1 As shown, the system includes: an interface caller 100, an interface service provider 200 and a service registration discovery platform 300, wherein the service registration discovery platform 300 is constructed based on a distributed key-value pair storage database, and the interface service provider 200 pre-registers the service on the service registration discovery platform 300;

[0051] The interface caller 100 is used to generate task data for the interface service provider 200 according to business needs, and send the task data to the service registration and discovery platform 300; the service registration and discovery platform 300 is used to store the task data; the interface service provider 200 is used to monitor the task data of the service registration and discovery platform 300, and update the task data after calling the corresponding processing method according to the task data; the interface caller 100 is also used to process business needs based on the updated task data.

[0052] Specifically, in the embodiment of the present invention, ETCD is used as a database to store business data, and ETCD is used as a service registration and discovery platform 300. Through the watch mechanism and task mechanism, the interface caller 100 and the interface service provider 200 can communicate with each other without using IP and port. Figure 2 As shown, the interface caller 100 includes: an application programming interface (API), a resource scheduling service (Scheduler) and / or a scheduled task service (Cron), which is only used as an example and is not limited to this. Among them, the API component provides an API interface service for the entire system to the outside, generally provides an HTTP interface, and is also the entrance to the entire system. This component contains most of the business logic; the Scheduler component is a resource scheduling service, which mainly provides scheduling functions for various resources, and the source of resources is the resource data in ETCD; the Cron component is a service for processing some scheduled tasks. The above services are uniformly considered to be the interface caller 100, which is the Client of the RPC interface. The main function is to send task requests to the Agent, process business logic, and receive task responses. ETCD can be used as a business / resource database, and at the same time as the service registration and discovery middleware of the entire system, providing service registration and service discovery functions, and also as a task flow agent, connecting the entire RPC call process, and recording all task information.

[0053] In some optional implementations, the Agent is an interface service provider 200, provides RPC interface capabilities, and implements interface functions, such as calling the Libvirt interface to implement operations such as creation, deletion, startup, and shutdown of virtual machines. Figure 3In the registration process shown, the Agent will collect various resources and configuration information of the host and report them to ETCD, generate a unique ID in ETCD: host_id as the key, such as hostA, and register itself with ETCD. The corresponding / host / host_id and / task / host_id are added in ETCD, so that the interface caller 100 can find itself, and the host's resource configuration information is entered into ETCD for use by API, Scheduler, etc. In addition, the Agent needs to define a series of RPC interface types, as well as the request and response data structures of each interface. The entire interaction with ETCD and the encapsulation of tasks are encapsulated in a unified framework.

[0054] In some optional implementations, the interface caller 100 generates task data for the interface service provider 200 according to business requirements, and sends the task data to the service registration and discovery platform 300, such as Figure 2 The Task Data shown can create / task / hostA / task_id in ETCD, and the task (task) status in the form of task request Requset is Requset (request). The interface service provider 200 monitors / task / hostA / task_id of ETCD, and executes a remote procedure call when it finds that the task status has changed. In the RPC response process of the interface service provider 200, after the Agent completes the task data processing, it adds the Response to / task / hostA / task_id and updates the / task / hostA / task_id status to Response. After the interface caller 100 (API) finds that the task status has changed, it takes out the Response content and processes the subsequent business logic. In the remote procedure call between the interface caller 100 and the interface service provider 200, both the business data and the RPC communication process can be recorded in ETCD. ETCD implements the functions of service registration and discovery, provides operation record backtracking, and the request is based on the ETCD watch mechanism, driven by data, which can greatly improve the overall QPS / TPS of the service. Based on the remote procedure call system provided by the embodiment of the present invention, those skilled in the art can quickly develop distributed applications, allowing developers to focus more on business logic without paying too much attention to the underlying communication framework.

[0055] The remote procedure call system provided by the embodiment of the present invention builds a service registration and discovery platform based on a distributed key-value pair storage database, and pre-registers the interface service provider on the service registration and discovery platform. The interface service provider stores the task data between the interface caller and the interface service provider. The interface caller issues the task data according to the business requirements. The interface service provider monitors the task data and updates the task data after calling the corresponding processing method based on the task data. The interface call is then processed to process the business requirements. By building a service registration and discovery platform, the present invention can enable services to communicate with each other without using IP and ports based on the watch mechanism and the task mechanism, and record relevant data to avoid dependence on components.

[0056] According to an embodiment of the present invention, a remote procedure call method embodiment is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0057] In this embodiment, a remote procedure call method is provided, which can be used for a mobile terminal including an interface caller, such as a computer, etc. Figure 4 is a flowchart of a remote procedure call method according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps:

[0058] Step S401: Generate task data for the interface service provider according to business requirements.

[0059] Step S402: Send the task data to the service registration and discovery platform, and monitor the task data.

[0060] Step S403: If it is monitored that the task data is updated, the business demand is processed according to the updated task data.

[0061] Specifically, in the embodiment of the present invention, Figure 5As shown, the API executes the corresponding tasks according to the business process. When it is necessary to remotely call the interface service provider, a task is created according to business needs, and the interface service provider to be called is specified, such as specifying to send it to hostA. During the RPC request process, the API will send task data containing task details to ETCD, that is, create / task / hostA / task_id in ETCD. If the current task is an asynchronous task, after sending the task data, it will directly process the subsequent business process without waiting for the task status to change. The task status is updated to done after the Agent completes the execution; if it is a synchronous task, the API watches the task / task / hostA / task_id, that is, it listens to the sent task data and waits for the Agent to receive the task and reply after processing. As shown Figure 6 As shown in the figure, when the API finds that the task status has changed, it takes out the Response content for parsing and processes the subsequent business logic.

[0062] The remote procedure call method applied to the interface caller provided in the embodiment of the present invention can implement the remote procedure call of the interface service provider by issuing task data on the service registration and discovery platform and monitoring the task data, thereby completing the business process of the system where the interface caller is located.

[0063] In this embodiment, a remote procedure call method is provided, which can be used for a mobile terminal including an interface service provider, such as a computer, etc. Figure 7 is a flowchart of a remote procedure call method according to an embodiment of the present invention. Figure 7 As shown, the process includes the following steps:

[0064] Step S701: Based on the registration information pre-registered on the service registration and discovery platform, monitor the task data of the service registration and discovery platform.

[0065] Step S702: after monitoring the task data, calling the corresponding processing method based on the task data.

[0066] Step S703: update the task data according to the processing result.

[0067] Specifically, in the embodiment of the present invention, Figure 5As shown in the figure, taking hostA as an example, hostA monitors the task data in ETCD. When watching the newly added task in / task / hostA, it obtains and parses the task content, calls the corresponding processing method according to the RPC interface type in the task, and after the processing is completed, adds the Response to / task / hostA / task_id and updates the / task / hostA / task_id status to Response.

[0068] The remote procedure call method applied to the interface service provider provided in the embodiment of the present invention can respond to the remote procedure call of the interface caller in a timely manner by monitoring the task data of the service registration and discovery platform, thereby realizing communication between distributed service systems.

[0069] The embodiment of the present invention also provides a computer device having the above Figure 1 The remote procedure call system shown.

[0070] See also Figure 8 , Figure 8 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Figure 8 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 8 A processor 10 is taken as an example.

[0071] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0072] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0073] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0074] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0075] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0076] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0077] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0078] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A remote procedure call system, comprising: The interface caller and the interface service provider are characterized in that they also include: a service registration and discovery platform, wherein the service registration and discovery platform is constructed based on a distributed key-value pair storage database, and the interface service provider pre-registers the service on the service registration and discovery platform; The interface caller is used to generate task data for the interface service provider according to business requirements, and send the task data to the service registration and discovery platform; The service registration and discovery platform is used to store the task data; The interface service provider is used to monitor the task data of the service registration and discovery platform, and update the task data after calling the corresponding processing method according to the task data; The interface caller is also used to process the business demand based on the updated task data.

2. The system according to claim 1, characterized in that The interface caller includes: an application program interface, a resource scheduling service and / or a scheduled task service.

3. The system according to claim 1, characterized in that The interface service provider pre-registers the service on the service registration and discovery platform, including: Generate identification information according to the host machine corresponding to the interface service provider; Obtain resource information and configuration information of the host machine collected by the interface service provider, and store the information; The interface type, request data structure and response data structure of the remote procedure call defined by the interface service provider to the host are obtained.

4. A remote procedure call method, characterized in that: Applied to the interface caller, the methods include: Generate task data for interface service providers based on business needs; Send the task data to the service registration and discovery platform, and monitor the task data; If it is monitored that the task data is updated, the business demand is processed according to the updated task data.

5. The method according to claim 4, characterized in that The monitoring of the task data includes: If the business requirement is an asynchronous task, other business requirements are processed according to the business process, and the task data is monitored by polling; If the business requirement is a synchronous task, the task data is monitored in real time.

6. A remote procedure call method, characterized in that: Applied to the interface service provider, the method includes: Based on the registration information pre-registered on the service registration and discovery platform, monitoring the task data of the service registration and discovery platform; If the task data is monitored, a corresponding processing method is called based on the task data; The task data is updated according to the processing result.

7. The method according to claim 6, characterized in that The calling of a corresponding processing method based on the task data includes: Parsing the task data to determine the interface type of the remote procedure call; The corresponding processing method is called according to the interface type.

8. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the remote procedure call method described in any one of claims 4 to 5 or claims 6 to 7 by executing the computer instructions.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the remote procedure call method according to any one of claims 4 to 5 or claims 6 to 7.

10. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions are used to cause a computer to execute the remote procedure call method according to any one of claims 4 to 5 or claims 6 to 7.

Images