JSON Diagnostics & Debugger Visualizers

arrp provides built-in metrics gathering and debugging visualizers to monitor resource usage and state during development and in production.

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Enabling JSON Serialization

JSON support is conditionally compiled. To enable the .to_json() methods on resource_pool<T> and resource_guard<T>, include nlohmann/json.hpp before <siddiqsoft/arrp.hpp>:

#include <nlohmann/json.hpp>
#include <siddiqsoft/arrp.hpp>
#include <iostream>

int main()
{
    siddiqsoft::arrp::resource_pool<std::string> pool {8};
    pool.seed("item-1");

    // Dump pool diagnostics to JSON
    nlohmann::json stats = pool.to_json();
    std::cout << stats.dump(2) << '\n';
}

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Pool JSON Schema & Fields

Calling pool.to_json() returns a JSON object with the following telemetry fields:

Field Name	Type	Description
_typver	string	Type identifier string (e.g. "siddiqsoft.arrp.resource_pool/0.0.0").
capacity	number	Configured initial capacity (clamped between 1 and 255).
size	number	Current number of available (idle) resources in pool.
peaksize	number	Maximum number of idle resources observed in the pool concurrently.
seeds	number	Total number of resources added via seed().
autoadds	number	Total number of resources created dynamically by the factory callback.
borrows	number	Total number of successful borrow operations (try_borrow / try_borrow_create).
returns	number	Total number of resources returned back to pool by valid guards.
abandons	number	Total number of resources discarded (invalidated or moved out).
loans	number	Currently checked-out active guards (borrows - returns - abandons).
items	array	Array representation of available items (only available for std::string and nlohmann::json pools).

Example Output

{
  "_typver": "siddiqsoft.arrp.resource_pool/0.0.0",
  "capacity": 8,
  "size": 2,
  "peaksize": 4,
  "seeds": 4,
  "autoadds": 1,
  "borrows": 3,
  "returns": 2,
  "abandons": 0,
  "loans": 1
}

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Visual Studio & VS Code Natvis Visualizer

The repository includes a custom Natvis file located at SiddiqSoft.arrp.natvis.

When debugging C++ code in Visual Studio or VS Code (with C/C++ extension), the Natvis file formats resource_pool<T> and resource_guard<T> objects cleanly in the Watch and Locals windows:

• resource_pool<T>: Displays active pool size, capacity, loan count, borrow/return metrics, and expands available queue elements cleanly.
• resource_guard<T>: Displays validity state (valid / invalid), held value reference, and underlying error code.

[!TIP] When using arrp via the NuGet package, the Natvis file is linked into MSBuild targets automatically!