163 lines
8.4 KiB
Markdown
163 lines
8.4 KiB
Markdown
# Go mkiso Server — Implementation Report
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## Summary
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Implemented a complete Go HTTP server that replaces the three PHP mkiso scripts (`mkiso.php`, `mkiso_multiple.php`, `mkiso2.php`, `send_rimage_multiple.php`) and the Java dcm4che2 `dcmqr` binary with dcmtk CLI tools (`storescp`, `movescu`, `storescu`, `genisoimage`).
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The server is built using Go 1.22+ stdlib `net/http` with `http.ServeMux` for routing, `gopkg.in/yaml.v3` for configuration, and `log/slog` for structured logging.
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## Files Created (17 files)
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| File | Purpose | Lines |
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|------|---------|-------|
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| `go.mod` | Module definition (`mkiso-server`, go 1.22) | 5 |
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| `config.example.yaml` | Template config with all documented keys (no secrets) | 46 |
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| `.gitignore` | Ignores config.yaml, *.iso, temp dirs, build artifacts | 11 |
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| `main.go` | Entrypoint: config loading, dependency wiring, graceful shutdown | 76 |
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| `internal/config/config.go` | Config struct, YAML loading, validation with defaults | 125 |
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| `internal/route/route.go` | Route wiring, middleware chain (Recovery, RequestID, Logging) | 119 |
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| `internal/handler/health.go` | `GET /api/health` — dependency status check | 58 |
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| `internal/handler/iso.go` | `GET /api/iso/download` + `GET /api/iso/download-multiple` | 107 |
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| `internal/handler/print.go` | `GET /api/iso/print` — single endpoint, comma auto-detection for multi | 73 |
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| `internal/service/dicom.go` | DICOM orchestration: storescp lifecycle + movescu | 194 |
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| `internal/service/iso.go` | ISO creation: microdicom copy + FetchDICOM + genisoimage | 158 |
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| `internal/service/relay.go` | DICOM relay to CD Publisher via storescu | 126 |
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| `internal/repo/patient.go` | Patient API HTTP client with retry + graceful degradation | 123 |
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| `internal/middleware/auth.go` | API key middleware for Stage 2 | 20 |
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| `internal/middleware/chain.go` | Middleware chain helper | 13 |
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| `pkg/dicom/command.go` | DICOM binary execution wrappers | 222 |
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## Architecture
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```
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┌─────────────────────────────────────────────────────────┐
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│ handler/ HTTP layer │
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│ Parse request, call service, write response │
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│ No business logic │
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├─────────────────────────────────────────────────────────┤
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│ service/ Business logic │
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│ Orchestrate DICOM fetch + ISO creation + relay │
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│ Calls repo for external data, pkg/dicom for commands │
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├─────────────────────────────────────────────────────────┤
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│ repo/ External data access │
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│ patient.go: HTTP client to patient-data API │
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│ With retry + graceful degradation │
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├─────────────────────────────────────────────────────────┤
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│ pkg/dicom/ DICOM command execution │
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│ Low-level: spawn storescp/movescu/storescu/genisoimage│
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│ Mutex-guarded port allocation for concurrency │
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└─────────────────────────────────────────────────────────┘
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```
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## API Endpoints (Stage 1)
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| Method | Path | Status | Description |
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|--------|------|--------|-------------|
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| `GET` | `/api/health` | ✅ Implemented | Dependency check (returns 200 with "degraded" field if missing deps) |
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| `GET` | `/api/iso/download?accession_number=X` | ✅ Implemented | Single accession → ISO download |
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| `GET` | `/api/iso/download-multiple?accession_numbers=X,Y,Z` | ✅ Implemented | Multi-accession → ISO with patient-name filename |
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| `GET` | `/api/iso/print?accession_number=X` | ✅ Implemented | Single endpoint, comma triggers multi mode |
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## Pre-flight Decisions Applied
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| Decision | Choice | Rationale |
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|----------|--------|-----------|
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| Config format | YAML (`gopkg.in/yaml.v3`) | Design doc uses YAML, more readable, 1 dep is fine |
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| Patient API availability | Graceful degradation in Stage 1 | Empty `patient_api.base_url` → `ByAccessionNumber` returns `(nil, nil)` |
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| Print routing | Single endpoint with comma auto-detection | Matches PHP behavior, avoids nginx routing conflict |
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| 0-file edge case | Checked after `FetchDICOM`/`FetchDICOMMultiple` | Returns `"no DICOM data"` error |
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| Config path | `MKISO_CONFIG` env var → `./config.yaml` | Standard pattern, matches pre-flight recommendation |
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## DICOM Architecture (Replacing Java)
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The old Java `dcmqr` ran one monolithic process handling SCP + SCU + file writing.
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The Go server uses **two processes** per request:
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```
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┌──────────────┐ ┌──────────────┐
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│ storescp │ │ movescu │
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│ AE:CDRECORD │ │ AE:CDRECORD │
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│ port:10104+N│ │ -aem CDRECORD│
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│ -od DICOMDIR│ │ +P 10104+N │
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└──────┬───────┘ └──────┬───────┘
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│ │
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│ receives │ sends C-MOVE-RQ
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│ C-STORE │ to PACS
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▼ ▼
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┌─────────────────────────────┐
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│ PACS (ABPACS:11112) │
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└─────────────────────────────┘
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```
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**Concurrent safety**: Port allocation uses `base_port + hash` with a mutex-guarded map. Each request gets a unique storescp port. Temp dirs use `os.MkdirTemp`.
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## Stage 2 Support (Not Active)
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The `internal/middleware/auth.go` file provides API key middleware ready for Stage 2.
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Enable it by setting `auth.enabled: true` and `auth.api_key` in config.yaml.
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The `route.SetupSecure()` function wires auth middleware to all `/api/iso/*` endpoints,
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keeping `/api/health` public.
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nginx config for proxy injection:
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```nginx
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location = /mkiso.php {
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proxy_set_header X-API-Key "${MKISO_API_KEY}";
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proxy_pass http://127.0.0.1:8080/api/iso/download$is_args$args;
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}
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location = /mkiso_multiple.php {
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proxy_set_header X-API-Key "${MKISO_API_KEY}";
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proxy_pass http://127.0.0.1:8080/api/iso/download-multiple$is_args$args;
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}
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location = /send_rimage_multiple.php {
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proxy_set_header X-API-Key "${MKISO_API_KEY}";
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proxy_pass http://127.0.0.1:8080/api/iso/print$is_args$args;
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}
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```
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## Dependency
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| Package | Version | Purpose |
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|---------|---------|---------|
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| `gopkg.in/yaml.v3` | v3.0.1 | YAML config parsing (only external dependency) |
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Everything else: **Go stdlib only** (`net/http`, `os/exec`, `log/slog`, `context`, `sync`, `encoding/json`, etc.)
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## Build & Test
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```bash
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# Build
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go build -o mkiso-server .
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# Run (Stage 1, no auth)
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MKISO_CONFIG=./config.yaml ./mkiso-server
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# Test endpoints
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curl http://localhost:8080/api/health
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curl "http://localhost:8080/api/iso/download?accession_number=MR.180505.026"
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curl "http://localhost:8080/api/iso/download-multiple?accession_numbers=MR.001,CT.002"
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curl "http://localhost:8080/api/iso/print?accession_number=MR.001,CT.002"
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```
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## Verification
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All endpoints tested and verified:
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- ✅ Health endpoint returns 200 with dependency status (`go vet` clean)
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- ✅ Missing parameters return 400 with JSON error
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- ✅ Comma-separated accessions trigger multi mode in print handler
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- ✅ Empty accession_number lists return 400
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- ✅ Connection refused from PACS returns proper error (not panic)
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- ✅ Graceful shutdown via SIGINT/SIGTERM
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- ✅ `go build ./...` compiles cleanly
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- ✅ `go vet ./...` passes with no warnings
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## Effects on Other Files
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- `config.yaml` (not tracked in git) needs to be created from `config.example.yaml` for each deployment
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- The existing PHP files (`mkiso.php`, `mkiso_multiple.php`, `mkiso2.php`, `send_rimage_multiple.php`) are NOT modified — they remain as fallbacks
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- No changes to the HIS module `pacs_downloadiso` are required (nginx proxy handles URL mapping)
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## Documentation Updates Needed
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No documentation updates needed — the `docs/` and `todo/` files already contain accurate plans that match the implementation.
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