Add configurable boundaries for speed parameter

[michalkulakowski]

🛠 Summary

JIRA/Issue if applicable.
Describe the changes.

🧪 Checklist

• Unit tests added.
• The documentation updated.
• Change follows security best practices.
  ``

[Copilot]

Pull request overview

This PR adds configurable validation bounds for the Text-to-Speech request speed parameter via T2sCalculatorOptions, and adds a size-cap guard for synthesized audio output to prevent oversized allocations/responses.

Changes:

• Add speed_min / speed_max options to T2sCalculatorOptions (with defaults) and enforce them during request processing.
• Add a defensive size check in prepareAudioOutput() consistent with existing decode-path size limits.
• Extend unit tests to cover default/custom speed bounds and synthesized-output size-cap behavior.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/test/audio/text2speech_test.cpp	Adds request-level tests for default speed bounds and config-level test for custom bounds.
src/test/audio/audio_utils_test.cpp	Adds tests ensuring prepareAudioOutput() enforces size caps and rejects invalid parameters.
src/audio/text_to_speech/t2s_calculator.proto	Introduces configurable speed_min / speed_max options with defaults.
src/audio/text_to_speech/t2s_calculator.cc	Enforces speed bounds when parsing TTS requests.
src/audio/audio_utils.cpp	Adds overflow/size-cap validation for synthesized WAV output buffers.

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[mzegla]

Does it propagate to the logs? I would use speed_min and speed_max to match naming in graph.pbtxt

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (3)

src/audio/text_to_speech/t2s_calculator.cc:149

• The current bounds check allows NaN (or misconfigured NaN bounds) to slip through because both (speed < speedMin) and (speed > speedMax) are false for NaN. This can bypass validation and pass an invalid speed into the GenAI pipeline. Consider rewriting the check to use a positive-range predicate and explicitly validate the configured bounds (e.g., speed_min <= speed_max).

                // Validate speed bounds regardless of whether it came from request or default
                const auto& calcOptions = cc->Options<T2sCalculatorOptions>();
                const float speedMin = calcOptions.speed_min();
                const float speedMax = calcOptions.speed_max();
                if (speed < speedMin || speed > speedMax) {

src/audio/audio_utils.cpp:264

• If drwav_write_pcm_frames() fails (framesWritten != totalSamples), the function throws without calling drwav_uninit() or freeing the partially built *ppData, which can leak memory. Since this function now has additional throw paths, it would be safer to make the whole write + post-write size validation exception-safe and free/uninit on every failure path.

    // Validate the actual WAV container size (includes RIFF/fmt/fact/data header
    // overhead that the pre-write check did not account for).
    try {
        validateAudioFileSizeAgainstMaxValue(pDataSize);
    } catch (...) {

src/test/audio/text2speech_test.cpp:389

• The new CustomSpeedBoundsConfigured test verifies that the graph config accepts speed_min / speed_max, but it doesn’t verify that these configured bounds actually affect request handling (e.g., speed=0.4 rejected when speed_min=0.5). Since the PR’s main feature is configurable bounds, it would be helpful to add an integration-style test that loads a graph/config with custom bounds and asserts both reject/accept behaviors at runtime.

TEST_F(Text2SpeechConfigTest, CustomSpeedBoundsConfigured) {
    ConstructorEnabledModelManager manager;
    std::string testPbtxt = R"(
    input_stream: "HTTP_REQUEST_PAYLOAD:input"
    output_stream: "HTTP_RESPONSE_PAYLOAD:output"

[mzegla]

1. Doesn't validateAudioFileSizeAgainstMaxValue also need a try catch?
2. What is the result of rethrowing here regarding what user - client and admin - see in the response message and logs.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (3)

src/audio/text_to_speech/t2s_calculator.cc:92

• Open() treats an invalid speed_min/speed_max configuration as an InternalError. This is a user configuration error and should use InvalidArgumentError so it is surfaced as a client/config validation issue rather than an internal server failure.

        const float speedMax = calcOptions.speed_max();
        // !(speedMin <= speedMax) is true for inverted ranges and for any NaN bound.
        if (!(speedMin <= speedMax)) {
            return absl::InternalError(
                absl::StrCat("Invalid T2sCalculatorOptions: speed_min (", speedMin, ") must be <= speed_max (", speedMax, ")"));

src/test/audio/audio_utils_test.cpp:497

• prepareAudioOutput allocates the WAV buffer via dr_wav; freeing it with free() can be incorrect if dr_wav.h is configured with custom allocators (the production path uses drwav_free). This can lead to allocator-mismatch crashes in tests under some builds.

    if (ppData) {
        free(ppData);  // drwav allocates via DRWAV_MALLOC
    }

src/audio/text_to_speech/t2s_calculator.cc:158

• The out-of-range speed error message does not include the actual invalid speed value, which makes debugging client requests harder.

                if (!(speedMin <= speed && speed <= speedMax)) {
                    return absl::InvalidArgumentError(
                        absl::StrCat("speed must be between speed_min (", speedMin, ") and speed_max (", speedMax, ")"));