Add error_generator test worker and handle_error decorator

CLAUDE.md

@@ -413,6 +413,7 @@ Test/sample workers live in `workers/annotations/` and are built with the `testw
 
 - **`random_squares`**: Generates random square polygon annotations. Uses `WorkerClient` for batch mode across XY/Z/Time. Useful for quickly testing annotation pipelines.
 - **`sample_interface`**: Demonstrates every available interface type (`notes`, `number`, `text`, `select`, `checkbox`, `channel`, `channelCheckboxes`, `tags`, `layer`), all messaging functions (`sendProgress`, `sendWarning`, `sendError`), and batch mode via `WorkerClient`.
+- **`error_generator`**: Generates various error conditions (warnings, errors, HTTP 500/503/504, OOM, crashes) via checkboxes for testing frontend error reporting.
 
 Build test workers:
 ```bash

REGISTRY.md

@@ -7,13 +7,13 @@ Auto-generated by `generate_worker_docs.py` -- do not edit manually.
 
 | Category | Count |
 |----------|------:|
-| Annotation Workers | 26 |
+| Annotation Workers | 27 |
 | Property Workers -- Blobs | 10 |
 | Property Workers -- Points | 8 |
 | Property Workers -- Lines | 3 |
 | Property Workers -- Connections | 2 |
 | Test / Sample Workers | 7 |
-| **Total** | **56** |
+| **Total** | **57** |
 
 ## Annotation Workers
 
@@ -33,6 +33,7 @@ Create new annotations by segmenting images or connecting existing annotations.
 | Crop | Crops images, allowing you to drop particular slices of data and crop to blobs or recta... |  | Yes | [docs](workers/annotations/crop/CROP.md) |
 | Deconwolf Deconvolution | Deconvolves images using Richardson-Lucy algorithm with Born-Wolf PSF model (GPU-accele... | Yes | Yes | [docs](workers/annotations/deconwolf/DECONWOLF.md) |
 | Deepcell |  | Yes |  | [docs](workers/annotations/deepcell/DEEPCELL.md) |
+| Error generator | Generates various error conditions for testing frontend error reporting. Check the boxe... |  |  | [docs](workers/annotations/error_generator/ERROR_GENERATOR.md) |
 | Gaussian Blur | Applies Gaussian blur to images |  | Yes | [docs](workers/annotations/gaussian_blur/GAUSSIAN_BLUR.md) |
 | H&E Deconvolution | Deconvolves H&E stains |  | Yes | [docs](workers/annotations/h_and_e_deconvolution/H_AND_E_DECONVOLUTION.md) |
 | Histogram Matching | Corrects images using histogram matching |  | Yes | [docs](workers/annotations/histogram_matching/HISTOGRAM_MATCHING.md) |

annotation_utilities/annotation_utilities/progress.py

@@ -1,6 +1,56 @@
+import functools
+import re
+
 from annotation_client.utils import sendProgress, sendWarning, sendError
 
 
+def _friendly_error_message(exc):
+    """Convert an exception into a user-friendly message."""
+    text = str(exc)
+    check_logs = "Check logs for details."
+
+    # HTTP status code errors (from girder_client.HttpError)
+    http_match = re.search(r'HTTP error (\d+)', text)
+    if http_match:
+        code = int(http_match.group(1))
+        messages = {
+            500: "Server error. " + check_logs,
+            502: "Server error. " + check_logs,
+            503: "Servers busy. Try again in "
+                 "a few minutes.",
+            504: "Servers busy. Try again in "
+                 "a few minutes.",
+        }
+        return messages.get(
+            code, f"HTTP error {code}. " + check_logs
+        )
+
+    if isinstance(exc, MemoryError):
+        return "Out of memory. " + check_logs
+
+    return f"{type(exc).__name__}. {check_logs}"
+
+
+def handle_error(func):
+    """Decorator that catches exceptions, sends a
+    user-friendly error via sendError(), then re-raises.
+
+    Usage:
+        @handle_error
+        def compute(datasetId, apiUrl, token, params):
+            ...
+    """
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        try:
+            return func(*args, **kwargs)
+        except Exception as exc:
+            msg = _friendly_error_message(exc)
+            sendError(msg, info="Check logs for details.")
+            raise
+    return wrapper
+
+
 def update_progress(processed, total, message):
     """
     Update the progress of the worker. If there are more than 100 objects,

build_test_workers.sh

@@ -4,7 +4,7 @@
 # Test Worker Build & Test Script
 # =============================================================================
 #
-# Builds and tests the test/sample workers (random_squares, sample_interface).
+# Builds and tests the test/sample workers (random_squares, sample_interface, error_generator).
 # These are workers used for testing and development, not production.
 #
 # Usage:

docker-compose.yml

@@ -251,6 +251,15 @@ services:
       - test-worker-base
     profiles: ["testworker"]
 
+  error_generator:
+    build:
+      context: .
+      dockerfile: ./workers/annotations/error_generator/Dockerfile
+    image: annotations/error_generator:latest
+    depends_on:
+      - test-worker-base
+    profiles: ["testworker"]
+
   # Test services
   blob_metrics_test:
     build:

workers/annotations/error_generator/Dockerfile

@@ -0,0 +1,12 @@
+FROM nimbusimage/test-worker-base:latest
+
+# Copy the entrypoint script
+COPY --chown=$MAMBA_USER:$MAMBA_USER ./workers/annotations/error_generator/entrypoint.py /
+
+LABEL isUPennContrastWorker="" \
+      isAnnotationWorker="" \
+      interfaceName="Error generator" \
+      interfaceCategory="Testing" \
+      description="Generates various error conditions for testing frontend error reporting"
+
+ENTRYPOINT ["/usr/local/bin/_entrypoint.sh", "python", "/entrypoint.py"]

workers/annotations/error_generator/ERROR_GENERATOR.md

@@ -0,0 +1,32 @@
+# Error generator
+
+**Type:** Annotation Worker  
+**Interface Category:** Testing  
+
+## Description
+
+Generates various error conditions for testing frontend error reporting. Check the boxes below to trigger specific error types.
+
+## Interface Parameters
+
+| Parameter | Type | Required | Default | Range / Options | Description |
+|-----------|------|:--------:|---------|-----------------|-------------|
+| **Send warning message** | `checkbox` |  | False | -- | Sends a warning via sendWarning() — worker continues running. |
+| **Send error message** | `checkbox` |  | False | -- | Sends an error via sendError() — worker continues running. |
+| **Crash immediately** | `checkbox` |  | False | -- | Raises an unhandled exception immediately (no progress shown). |
+| **Crash after progress** | `checkbox` |  | False | -- | Shows progress updates then crashes mid-way with a traceback. |
+| **Simulate HTTP 500** | `checkbox` |  | False | -- | Simulates an HTTP 500 Internal Server Error traceback like girder_client.HttpError. |
+| **Simulate HTTP 503** | `checkbox` |  | False | -- | Simulates an HTTP 503 Service Unavailable error. |
+| **Simulate HTTP 504** | `checkbox` |  | False | -- | Simulates an HTTP 504 Gateway Timeout error. |
+| **Simulate OOM kill** | `checkbox` |  | False | -- | Simulates an out-of-memory crash (MemoryError). |
+| **Delay before error (seconds)** | `number` |  | 1 | 0 - 30 seconds | How long to wait before triggering each error condition. |
+
+## Files
+
+| File | Description |
+|------|-------------|
+| `entrypoint.py` | Main worker logic -- `interface()` defines the UI, `compute()` runs the analysis |
+| `Dockerfile` | Docker build configuration (x86_64 / production) |
+
+---
+_This file is auto-generated by `generate_worker_docs.py`. To update, edit `entrypoint.py` and re-run the generator, or open a PR -- the Claude Code hook regenerates docs automatically._