JooHyukKim commented on code in PR #20691: URL: https://github.com/apache/pulsar/pull/20691#discussion_r1251654400
########## pip/pip-280.md: ########## @@ -0,0 +1,117 @@ +# Title: Refactor CLI Argument Parsing Logic for Measurement Units using JCommander's custom converter + +## Motivation + +In the current Pulsar codebase, the logic to parse CLI arguments for measurement units like time and bytes is +scattered across various CLI classes. Each value read has its distinct parsing implementation, leading to a lack of code +reuse. + +## Goals + +This PIP is to refactor the argument parsing logic to leverage the `@Parameter.converter` +functionality provided by JCommander [link 3]. This will isolate the measurement-specific parsing logic and increase +code +reusability. + +### In Scope + +- Refactor all `Cmd` classes to utilize the converter functionality of JCommander. This will streamline the parsing + logic and simplify the codebase. +- Refer to bottom section "Concrete Example", before "Links" +- Or on-going PR with small use case in https://github.com/apache/pulsar/pull/20663 + +### Out of Scope + +- Creation of a "util" module is out of the scope of this PIP. + +## Design & Implementation Details + +- The refactoring will be carried out on a class-by-class basis or per inner-class basis. +- Target command classes for this refactoring include + - `CmdNamespaces.java` + - `CmdTopics.java`, + - `CmdTopicPolicies.java`. + +## Note + +- Additional classes may be included as the refactoring progresses. +- Respective PRs will be added here also. + +## Concrete Example + +Consider the code snippet +from [CmdNamespaces.java](https://github.com/apache/pulsar/blob/200fb562dd4437857ccaba3850bd64b0a9a50b3c/pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java#L2352-L2359) +for example. The existing code uses a local variable `maxBlockSizeStr` to temporarily store the value +of `--maxBlockSize` or `-mbs`. This is then parsed and validated in a separate section of the code. + +### BEFORE + +```java + @Parameter( + names = {"--maxBlockSize", "-mbs"}, + description = "Max block size (eg: 32M, 64M), default is 64MB s3 and google-cloud-storage requires this parameter", + required = false) +private String maxBlockSizeStr; +``` + +parsing like below .... + +```java + // parsing like.... + int maxBlockSizeInBytes=OffloadPoliciesImpl.DEFAULT_MAX_BLOCK_SIZE_IN_BYTES; + if(StringUtils.isNotEmpty(maxBlockSizeStr)){ + long maxBlockSize=validateSizeString(maxBlockSizeStr); + if(positiveCheck("MaxBlockSize",maxBlockSize) + &&maxValueCheck("MaxBlockSize",maxBlockSize,Integer.MAX_VALUE)) { + maxBlockSizeInBytes=Long.valueOf(maxBlockSize).intValue(); + } + } +``` + +### AFTER + +```java + @Parameter( + names = {"--maxBlockSize", "-mbs"}, + description = "Max block size (eg: 32M, 64M), default is 64MB s3 and google-cloud-storage requires this parameter", + required = false, converter = MemoryUnitToByteConverter.class) // <--- parsing logic "inline" easy to follow +private long maxBlockSizeStr=DEFAULT_MAX_BLOCK_SIZE_IN_BYTES; // <---- default value in line +``` + +... and actual parsing in isolation, ready for reuse like... + +```java +class MemoryUnitToByteConverter implements IStringConverter<Long> { Review Comment: Yes, if needed 👍🏻 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
