Joseph Doherty
7466a46aa7
The standalone design.md, kpi.md, operations.md, and the docs/plan/ phase tree were point-in-time planning artefacts now superseded by the topic-organized docs/ tree (Architecture/, Features/, Operations/, Reference/, Testing/). The DL260/ folder mixed a device-reference doc, a test fixture, a sample test, and a screenshot; its contents now live in their natural homes (dl205.md + mbtcp_settings.JPG under docs/Reference/, dl205.json next to its launcher in tests/sim/, sample test dropped). All cross-references in the surviving docs, README, CLAUDE.md, the config template, and source comments are repointed to the new locations. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
127 lines
6.9 KiB
Markdown
127 lines
6.9 KiB
Markdown
# mbproxy
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A .NET 10 Windows Service that sits inline as a Modbus TCP proxy in front of a fleet of AutomationDirect DirectLOGIC DL205/DL260 controllers, rewriting BCD-encoded registers bidirectionally so upstream clients can read and write them as plain integers. The proxy also offers an opt-in per-tag response cache (default OFF) for FC03/FC04 reads with bounded operator-configured staleness — see [`docs/Architecture/ResponseCache.md`](docs/Architecture/ResponseCache.md) before enabling it.
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> ⚠ **32-bit BCD wire format is "two base-10000 digits in CDAB", not standard CDAB binary Int32.** A 32-bit BCD tag at address `A` decodes as `decimal = high * 10_000 + low` where `low` is the register at `A` and `high` is the register at `A+1`. Each word independently must be 0–9999. Standard Modbus clients (NModbus, FluentModbus, Wonderware DAServer) that interpret CDAB as straight binary Int32 will silently corrupt any value > 9999 on writes and read garbage on reads. Configure your client to send/receive each register as a separate base-10000 BCD digit pair, not as a single binary Int32. Full details in [`docs/Features/BcdRewriting.md`](docs/Features/BcdRewriting.md).
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## Hard constraints / prerequisites
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- **Windows 10 / Server 2019 or later, 64-bit.** No Linux or Docker support — the service uses `Microsoft.Extensions.Hosting.WindowsServices` and the Windows Event Log.
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- **Modbus TCP backends reachable** from the proxy host on port 502 (or the port configured per PLC). The H2-ECOM100 module caps simultaneous connections at **4 per PLC** — a fifth upstream client will fail to connect.
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- **Admin rights** to install the service (`install.ps1` requires elevation).
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- **No COM dependency** — this is a pure .NET 10 socket-level proxy (unlike the `.NET Framework 4.8 / x86` siblings in this repo).
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- **Python 3.10+** on the test machine to run the pymodbus-backed E2E simulator (not needed to run the service in production).
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## Layout
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```
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src/Mbproxy/ Main C# project (net10.0, Microsoft.NET.Sdk.Worker)
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tests/Mbproxy.Tests/ xUnit v3 test project (314 unit + 48 E2E tests)
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install/ PowerShell install/uninstall scripts and config template
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docs/ Architecture, features, operations, reference, and testing docs
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```
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## Resource index
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| Task | Go to |
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| Architecture entry point — listener topology, request flow, per-PLC isolation | [`docs/Architecture/Overview.md`](docs/Architecture/Overview.md) |
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| DL205/DL260 Modbus quirks (BCD, CDAB, octal V-memory, FC limits) | [`docs/Reference/dl205.md`](docs/Reference/dl205.md) |
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| pymodbus simulator profile (register seeds for E2E tests) | [`tests/sim/dl205.json`](tests/sim/dl205.json) |
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| Agent-oriented coding guide (architecture bullets, device quirks, phase context) | [`CLAUDE.md`](CLAUDE.md) |
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## Detailed documentation
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The `docs/` tree is organized by topic. Start with [`Architecture/Overview.md`](docs/Architecture/Overview.md) for the end-to-end picture; jump to the focused pages below when you need depth on one area.
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### Architecture
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- [`Architecture/Overview.md`](docs/Architecture/Overview.md) — Listener topology, request flow, per-PLC isolation.
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- [`Architecture/ConnectionModel.md`](docs/Architecture/ConnectionModel.md) — Single backend connection per PLC, TxId multiplexing, request-timeout watchdog, disconnect cascade.
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- [`Architecture/ReadCoalescing.md`](docs/Architecture/ReadCoalescing.md) — In-flight FC03/FC04 deduplication via `InFlightByKeyMap`.
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- [`Architecture/ResponseCache.md`](docs/Architecture/ResponseCache.md) — Opt-in per-tag response cache with bounded operator-configured staleness.
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### Features
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- [`Features/BcdRewriting.md`](docs/Features/BcdRewriting.md) — BCD codec, CDAB word order, FC03/04/06/16 scope, partial-overlap policy.
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- [`Features/HotReload.md`](docs/Features/HotReload.md) — `IOptionsMonitor`-driven config reload with per-change-kind reconcile rules.
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### Operations
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- [`Operations/Configuration.md`](docs/Operations/Configuration.md) — Full `appsettings.json` reference: every `Mbproxy:*` key, default, and validation rule.
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- [`Operations/StatusPage.md`](docs/Operations/StatusPage.md) — Admin endpoint surface (`/`, `/status.json`) with every JSON field documented.
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- [`Operations/Troubleshooting.md`](docs/Operations/Troubleshooting.md) — Diagnosis playbook keyed to log events and status counters.
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### Reference
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- [`Reference/LogEvents.md`](docs/Reference/LogEvents.md) — Stable `mbproxy.*` event catalog (28 events across 7 categories).
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### Testing
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- [`Testing/Simulator.md`](docs/Testing/Simulator.md) — pymodbus DL205 fixture, skip policy, and the load-bearing pymodbus 3.13 framer quirk.
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## Build and run
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**Build (Debug, multi-file — fast for iteration):**
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```powershell
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dotnet build Mbproxy.slnx -c Debug
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```
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**Publish (Release, single-file, win-x64):**
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```powershell
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.\install\publish.ps1 -Clean
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```
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Produces both flavours under `publish-out\`:
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| Flavour | Path | Size | Target prerequisite |
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| Self-contained | `publish-out\self-contained\Mbproxy.exe` | ~100 MB | None — bundles .NET 10 + ASP.NET Core runtime |
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| Framework-dependent | `publish-out\framework-dependent\Mbproxy.exe` | ~1.5 MB | .NET 10 + ASP.NET Core preinstalled |
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Pass `-OutputDir <path>` to publish elsewhere; omit `-Clean` to skip the wipe. The script wraps `dotnet publish src/Mbproxy/Mbproxy.csproj -c Release -r win-x64 [-p:SelfContained=false]` — run those directly if you only need one flavour.
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**Run tests:**
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```powershell
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dotnet test Mbproxy.slnx -c Debug # all tests
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dotnet test Mbproxy.slnx -c Debug --filter Category=Unit # unit tests only (no Python required)
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dotnet test Mbproxy.slnx -c Debug --filter Category=E2E # E2E tests (require Python + pymodbus)
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```
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**Run interactively (without installing as a service):**
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```powershell
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cd src/Mbproxy
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dotnet run --configuration Debug
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```
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Edit `src/Mbproxy/appsettings.json` to configure PLCs before running. The admin status page will be at `http://localhost:8080/` by default.
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## Install
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The `install/` directory holds the publish, install, and uninstall scripts. Quick path:
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```powershell
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# 1. Publish (produces publish-out\self-contained\ and publish-out\framework-dependent\)
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.\install\publish.ps1 -Clean
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# 2. Install (elevated PowerShell) — point at the flavour you want to deploy
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.\install\install.ps1 -PublishOutput .\publish-out\self-contained -Start
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# 3. Edit the config that was placed at %ProgramData%\mbproxy\appsettings.json
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# 4. Verify
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Invoke-WebRequest http://localhost:8080/ -UseBasicParsing
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```
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## Maintenance
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Documentation doctrine for this repo: [`../DOCS-GUIDE.md`](../DOCS-GUIDE.md).
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- This README routes to deep docs — it does not duplicate them.
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- Design decisions and rationale live in the `docs/` tree (Architecture, Features, Operations, Reference, Testing).
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- When the service's public surface or task→tool mapping changes, update this README and the root [`../CLAUDE.md`](../CLAUDE.md) index row.
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