Azure Data Factory Pipeline Debugger
Step-through debugging for ADF / Synapse pipelines without leaving VS Code.
Load pipeline JSON → set breakpoints on activities → dry-run with sample data → inspect intermediate outputs at each stage.
Highlights data type mismatches, missing linked service configs, and expression errors before you deploy.
Features
| Feature |
Description |
| Load & Parse |
Open any ADF / Synapse pipeline JSON and instantly see structure & dependencies |
| Set Breakpoints |
Click the red dot on any activity or press Toggle Breakpoint inside the JSON |
| Step-Through Debug |
Start (F5) → Step Over (F10) → Step Into (F11) → Continue → Stop (Shift+F5) |
| Dry-Run Simulation |
Every activity type is simulated — Copy, Lookup, ForEach, IfCondition, Switch, Web, Notebook, SQL, and more |
| Intermediate Outputs |
Click any activity to inspect its output JSON after execution |
| Expression Evaluator |
Full ADF expression language support — @pipeline(), @activity(), @concat(), @if(), 60+ functions |
| Diagnostics |
Linked service validation, dataset existence checks, schema compatibility, expression errors, policy warnings |
| Variable Inspector |
Watch pipeline variables and parameters change in real time |
| Sample Data |
Feed sample JSON into any activity to control simulation output |
Getting Started
- Install the extension (VSIX or Marketplace)
- Open a folder containing your ADF / Synapse pipeline JSON files
- Right-click a pipeline JSON → ADF Debugger: Load Pipeline
- The debug panel opens with your activities listed
- Click activities to set breakpoints → press ▶ Start
Commands
| Command |
Keybinding |
Description |
ADF Debugger: Load Pipeline |
— |
Load a pipeline JSON into the debugger |
ADF Debugger: Start / Resume |
F5 |
Start or continue debug execution |
ADF Debugger: Step Over |
F10 |
Execute the next activity |
ADF Debugger: Step Into |
F11 |
Step into container activities |
ADF Debugger: Continue |
F5 |
Run until next breakpoint or end |
ADF Debugger: Stop |
Shift+F5 |
Stop the current debug session |
ADF Debugger: Toggle Breakpoint |
— |
Set/remove breakpoint on activity at cursor |
ADF Debugger: Validate Pipeline |
— |
Run full diagnostics without debugging |
ADF Debugger: Set Sample Data |
— |
Provide sample output JSON for an activity |
Diagnostic Categories
The debugger checks for:
- Expression errors — invalid syntax, unknown functions, wrong argument counts
- Type mismatches — incompatible column types between Copy source and sink
- Missing linked services — referenced services not found in workspace
- Missing datasets — referenced datasets not found in workspace
- Missing dependencies —
dependsOn references to non-existent activities
- Circular dependencies — cycles in the activity dependency graph
- Unreachable activities — activities that can never execute due to graph structure
- Schema mismatches — source/sink column type incompatibilities in Copy activities
- Policy warnings — excessive retry counts or invalid timeout formats
- Variable/parameter errors — references to undefined variables or parameters
Pipeline JSON Structure
The debugger expects standard ADF / Synapse pipeline JSON:
{
"name": "MyPipeline",
"properties": {
"activities": [
{
"name": "CopyData",
"type": "Copy",
"dependsOn": [],
"typeProperties": {
"source": { "type": "AzureSqlSource" },
"sink": { "type": "AzureBlobSink" }
},
"inputs": [{ "referenceName": "SqlDataset", "type": "DatasetReference" }],
"outputs": [{ "referenceName": "BlobDataset", "type": "DatasetReference" }]
},
{
"name": "LogResult",
"type": "WebActivity",
"dependsOn": [
{ "activity": "CopyData", "dependencyConditions": ["Succeeded"] }
],
"typeProperties": {
"url": "@concat('https://api.example.com/log/', pipeline().RunId)",
"method": "POST"
}
}
],
"parameters": {
"env": { "type": "String", "defaultValue": "dev" }
},
"variables": {
"counter": { "type": "Integer", "defaultValue": 0 }
}
}
}
Settings
| Setting |
Default |
Description |
adfDebugger.linkedServiceFolder |
linkedService |
Folder name for linked service JSON files |
adfDebugger.datasetFolder |
dataset |
Folder name for dataset JSON files |
adfDebugger.sampleDataFolder |
.adf-debug/samples |
Folder for sample data files |
adfDebugger.maxExpressionDepth |
20 |
Max recursion depth for expression evaluation |
adfDebugger.showWarnings |
true |
Show warnings in Problems panel |
Supported Activity Types
Copy, Lookup, GetMetadata, Filter, ForEach, IfCondition, Switch, Until, Wait, SetVariable, AppendVariable, WebActivity, WebHook, ExecutePipeline, Notebook, SparkJob, SqlServerStoredProcedure, Script, Delete, Validation, Fail, Custom, ExecuteDataFlow, ExecuteSSISPackage.
License
MIT
