fix(mtconnect): the Agent refuses count ABOVE bufferSize, not at it (#825)

Live gate against the cppagent 2.7 fixture: count=16384 with bufferSize
16384 streams; 16385 is OUT_OF_RANGE ('count' must be less than 16385).
Warn only when SampleCount > bufferSize, pin both sides of the edge
against the live Agent, and correct the #804 wording that said 'at or
above'.
This commit is contained in:
Joseph Doherty
2026-11-11 01:38:48 -05:00
parent f8f6781a24
commit 8a6f0e3c84
11 changed files with 41 additions and 29 deletions
@@ -61,7 +61,8 @@ public sealed partial class MTConnectDriver : IDriverDiagnostics
/// <summary>
/// lmxopcua#825 — the configuration warning for a <see cref="MTConnectDriverOptions.SampleCount"/> the Agent
/// will refuse. An Agent answers <c>/sample?count=N</c> with <c>OUT_OF_RANGE</c> ("'count' must be less than
/// bufferSize") when <c>N ≥ bufferSize</c>, so such a driver never streams: it re-baselines from
/// bufferSize + 1") when <c>N &gt; bufferSize</c> — live-measured on cppagent 2.7 (bufferSize 16384: 16384 is
/// accepted, 16385 refused) — so such a driver never streams: it re-baselines from
/// <c>/current</c> and reports Degraded after three of them. Shared by <see cref="MTConnectDriverProbe"/>
/// (Test Connect) and the driver's initialize (deploy), so both say the same thing.
/// </summary>
@@ -69,10 +70,10 @@ public sealed partial class MTConnectDriver : IDriverDiagnostics
/// <param name="bufferSize">The Agent's buffer size, or null when its header did not say.</param>
/// <returns>The warning text, or <see langword="null"/> when the count fits (or the buffer size is unknown).</returns>
internal static string? SampleCountBufferWarning(int sampleCount, long? bufferSize) =>
bufferSize is { } size && sampleCount >= size
? $"SampleCount {sampleCount.ToString(CultureInfo.InvariantCulture)} is at or above the Agent's bufferSize "
bufferSize is { } size && sampleCount > size
? $"SampleCount {sampleCount.ToString(CultureInfo.InvariantCulture)} is above the Agent's bufferSize "
+ $"{size.ToString(CultureInfo.InvariantCulture)}: the Agent refuses every /sample stream (OUT_OF_RANGE), so "
+ "values will only re-baseline from /current and the driver reports Degraded. Set SampleCount below "
+ "values will only re-baseline from /current and the driver reports Degraded. Set SampleCount to at most "
+ $"{size.ToString(CultureInfo.InvariantCulture)}."
: null;
@@ -2350,7 +2350,7 @@ public sealed partial class MTConnectDriver
// #804 — the backoff above PACES a stream that only ever re-baselines, but each /current
// also marked the stream delivered, so it read Healthy for ever while no /sample chunk
// arrived (a SampleCount at or above the Agent's bufferSize is refused OUT_OF_RANGE on
// arrived (a SampleCount above the Agent's bufferSize is refused OUT_OF_RANGE on
// EVERY open). After MaxRebaselinesWithoutProgress in a row it is reported Degraded, and
// stays so (holdStalled) until a chunk is delivered.
if (!outcome.DeliveredAny &&
@@ -2363,7 +2363,7 @@ public sealed partial class MTConnectDriver
_logger.LogWarning(
outcome.Error,
"MTConnect driver {DriverInstanceId}: {Count} consecutive /current re-baselines of {AgentUri} without a single /sample chunk in between; reporting the stream Degraded until one is delivered. Values are re-baselined, not streamed. An Agent answering every /sample with OUT_OF_RANGE usually means SampleCount is at or above its bufferSize.",
"MTConnect driver {DriverInstanceId}: {Count} consecutive /current re-baselines of {AgentUri} without a single /sample chunk in between; reporting the stream Degraded until one is delivered. Values are re-baselined, not streamed. An Agent answering every /sample with OUT_OF_RANGE usually means SampleCount is above its bufferSize.",
_driverInstanceId, rebaselinesWithoutProgress, AgentDisplay(options));
}
@@ -135,7 +135,7 @@ public sealed class MTConnectDriverProbe : IDriverProbe
/// <summary>
/// The <c>/sample</c> <c>count</c> (lmxopcua#825). Not needed to reach the Agent, but read so Test Connect
/// can warn when it is at or above the Agent's <c>bufferSize</c> — a config the Agent will refuse on every
/// can warn when it is above the Agent's <c>bufferSize</c> — a config the Agent will refuse on every
/// stream. Absent ⇒ the driver's own default.
/// </summary>
public int? SampleCount { get; set; }
@@ -11,7 +11,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
/// <param name="BufferSize">
/// The Agent's observation ring-buffer size (the <c>/probe</c> <c>Header</c>'s <c>bufferSize</c>), or
/// <see langword="null"/> when the header omits it or it is not a positive integer. A <c>/sample</c>
/// <c>count</c> at or above it is refused <c>OUT_OF_RANGE</c> by the Agent (lmxopcua#825).
/// <c>count</c> above it is refused <c>OUT_OF_RANGE</c> by the Agent (lmxopcua#825; live: <c>count == bufferSize</c> is accepted).
/// </param>
public sealed record MTConnectProbeModel(IReadOnlyList<MTConnectDevice> Devices, long? BufferSize = null);
@@ -76,7 +76,7 @@ internal static class MTConnectXml
/// <remarks>
/// <b>Why this exists (#804).</b> A modern Agent (cppagent 2.x, the fixture's
/// <c>mtconnect/agent:2.7</c>) does not serve its error documents under HTTP 200 the way older
/// ones did: it answers an out-of-range <c>/sample?from=</c> — and a <c>count</c> at or above its
/// ones did: it answers an out-of-range <c>/sample?from=</c> — and a <c>count</c> above its
/// buffer — with <b>HTTP 400</b>, and an unknown device with <b>404</b>, each carrying a
/// well-formed <c>MTConnectError</c> body. A status check alone turns those into an
/// <see cref="HttpRequestException"/>, which the pump treats as a transient transport loss and
@@ -14,7 +14,7 @@
{
@if (_result.Ok && WarningOf(_result.Message) is { } warning)
{
@* Reachable but misconfigured (e.g. MTConnect SampleCount >= the Agent's bufferSize, #825): a probe
@* Reachable but misconfigured (e.g. MTConnect SampleCount > the Agent's bufferSize, #825): a probe
that answers Ok with a "WARNING:" message is shown amber with the warning, never a plain green OK. *@
<span class="chip chip-warn" title="@warning">
OK with warning &middot; @_result.LatencyMs?.ToString("F0") ms