vtysh: Add JSON output support for show memory

[ton31337]

No description provided.

[greptile-apps]

Greptile Overview

Greptile Summary

This PR adds JSON output support to the show memory command in both the library and vtysh layers.

Key Changes:

• Created new qmem_walker_json() function in lib/lib_vty.c that transforms memory statistics into JSON format, mirroring the existing qmem_walker() for text output
• Added JSON handling to the show_memory command definition to accept optional json parameter
• Implemented show_memory_send() helper function in vtysh/vtysh.c to coordinate JSON output across multiple daemons
• Updated vtysh command handler to properly route JSON requests through the new code path while preserving backward compatibility for non-JSON commands

Implementation Notes:

• The JSON walker properly handles conditional compilation with HAVE_MALLOC_USABLE_SIZE guards
• Memory types with zero max allocations are filtered out (matching text output behavior)
• Variable-size memory types are represented as "size": "variable" in JSON
• JSON output wraps daemon responses in a top-level object with daemon names as keys
• Mallinfo statistics are not included in JSON output (only in text mode)

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The implementation follows established patterns in the codebase, properly handles argument parsing, maintains backward compatibility, and includes appropriate conditional compilation guards. The code is clean, well-structured, and mirrors existing JSON implementations for similar commands.
• No files require special attention

Important Files Changed

Filename	Overview
lib/lib_vty.c	Added JSON output support for memory statistics with new qmem_walker_json function that mirrors the existing text walker
vtysh/vtysh.c	Extended show memory command to support JSON output with new show_memory_send helper function following existing patterns

Sequence Diagram

sequenceDiagram
    participant User
    participant vtysh as vtysh (CLI)
    participant daemon as Daemon (bgpd, zebra, etc.)
    participant lib_vty as lib_vty.c
    
    User->>vtysh: show memory [daemon] json
    
    alt JSON output requested
        vtysh->>vtysh: argv_find("json")
        vtysh->>vtysh: show_memory_send(daemon, true)
        vtysh->>User: Output "{"
        
        loop For each connected daemon
            vtysh->>vtysh: Check if daemon matches filter
            vtysh->>vtysh: Check if daemon is connected
            vtysh->>User: Output "daemon_name":
            vtysh->>daemon: vtysh_client_execute_name("do show memory json")
            daemon->>lib_vty: show_memory with json flag
            lib_vty->>lib_vty: use_json(argc, argv) returns true
            lib_vty->>lib_vty: json_object_new_object()
            lib_vty->>lib_vty: qmem_walk(qmem_walker_json, &jarg)
            
            loop For each memory group & type
                lib_vty->>lib_vty: qmem_walker_json()
                alt Memory group
                    lib_vty->>lib_vty: Create JSON array for group
                else Memory type
                    lib_vty->>lib_vty: Add memory stats to JSON
                end
            end
            
            lib_vty->>daemon: vty_json(vty, json)
            daemon->>vtysh: Return JSON output
            vtysh->>User: Output daemon's JSON data
        end
        
        vtysh->>User: Output "}"
    else Non-JSON output
        vtysh->>vtysh: show_one_daemon() or show_per_daemon()
        Note over vtysh,User: Existing flow unchanged
    end

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[Jafaral]

Not sure why Verify Source is complaining about a line that isn't part of this PR. https://github.com/FRRouting/frr/pull/20605/files#diff-223013206495788884d7c3f9d02f603f4ea7e4fbbc15e76b10f3df66996f64b2R219

[mjstapp]

Thanks, looks good to me!

[mjstapp]

ci:rerun

[riw777]

looks good