Troubleshooting Guide

This guide helps you diagnose and resolve common issues when using datagen commands.

Table of Contents

• Transpilation Errors
• Generation Errors
• Execution Errors
• Common File Issues

Transpilation Errors

Transpilation errors occur when datagen converts your .dg files to Go code.

1. “Model X should be in file named X.dg”

Problem: Model name doesn’t match filename.

Solution: Rename file or change model name to match.

users.dg

model users {  // ✓ Correct - matches filename
  // ...
}

// File: User.dg
model User {   // ✓ Correct - matches filename
  // ...
}

2. “Field X has no corresponding generation function”

Problem: You defined a field but forgot to create its generation function.

Solution: Add the missing generation function.

fields {
  name() string
  age() int
}

gens {
  func name() {
    return Name()
  }
  // Missing: func age() { ... }
}

3. “Generation function X has no corresponding field”

Problem: You created a generation function but forgot to define the field.

Solution: Add the missing field definition.

fields {
  name() string
  // Missing: age() int
}

gens {
  func name() {
    return Name()
  }
  func age() {  // No corresponding field
    return IntBetween(18, 65)
  }
}

4. “Parameterized field X requires calls section”

Problem: You have a parameterized field but no calls section.

Solution: Add the calls section with arguments.

fields {
  created_at(start time.Time, end time.Time) time.Time
}

gens {
  func created_at(start time.Time, end time.Time) {
    return DateBetween(start, end)
  }
}

// Missing calls section - add this:
calls {
  created_at(time.Now().AddDate(-1, 0, 0), time.Now())
}

5. “Syntax error in model file”

Problem: Invalid syntax in your .dg file.

Common issues:

• Missing braces {}
• Incorrect field syntax
• Invalid Go syntax in generation functions

Solution: Check your syntax carefully.

// Wrong
fields {
  name string  // Missing parentheses and type
}

// Correct
fields {
  name() string
}

Generation Errors

Generation errors occur when running datagen gen command.

1. “No .dg files found”

Problem: No model files found in the specified directory.

Solutions:

# Check current directory
pwd

# List .dg files
ls -la *.dg

# Use correct path
datagen gen ./models/*.dg
datagen gen .  # Current directory

2. “Build failed: Go compilation error”

Problem: Generated Go code has compilation errors.

Common causes:

• Invalid Go syntax in generation functions
• Missing imports
• Type mismatches

Solution: Check your generation functions for Go syntax errors.

// Wrong - invalid Go syntax
func name() {
  return Name(  // Missing closing parenthesis
}

// Correct
func name() {
  return Name()
}

3. “Permission denied” or “Access denied”

Problem: Cannot write to output directory.

Solutions:

# Check directory permissions
ls -la output/

# Create directory if it doesn't exist
mkdir -p output/

# Use different output directory
datagen gen users.dg -o /tmp/output

4. “Invalid output format”

Problem: Unsupported output format specified.

Solution: Use supported formats.

# Supported formats
datagen gen users.dg -f csv
datagen gen users.dg -f json
datagen gen users.dg -f xml
datagen gen users.dg -f stdout

Execution Errors

Execution errors occur when running datagen exec command.

1. “Config file not found”

Problem: Configuration file doesn’t exist.

Solution: Create or specify correct config file.

# Create config.json
{
  "models": [...],
  "sinks": [...]
}

# Use config file
datagen exec users.dg --config config.json

2. “Database connection failed”

Problem: Cannot connect to database sink.

Common causes:

• Wrong connection details
• Database not running
• Network issues
• Authentication problems

Solution: Check your database configuration.

{
  "sinks": [
    {
      "sink_name": "mysql_sink",
      "sink_type": "mysql",
      "config": {
        "host": "localhost",
        "port": "3306",
        "user": "root",
        "password": "password",
        "database": "testdb"
      }
    }
  ]
}

3. “Model not found in config”

Problem: Model referenced in config doesn’t exist.

Solution: Ensure model name matches exactly.

{
  "models": [
    {
      "model_name": "users",
      "target_sinks": ["mysql_sink"],
      "count": 1000
    }
  ]
}

4. “Sink not found”

Problem: Model references a sink that doesn’t exist in config.

Solution: Define the sink in your config file.

{
  "models": [
    {
      "model_name": "users",
      "target_sinks": ["mysql_sink"]
    }
  ],
  "sinks": [
    {
      "sink_name": "mysql_sink",
      "sink_type": "mysql",
      "config": {...}
    }
  ]
}

Common File Issues

1. “File not found”

Problem: Specified file doesn’t exist.

Solutions:

# Check if file exists
ls -la users.dg

# Use absolute path
datagen gen /full/path/to/users.dg

# Use relative path
datagen gen ./models/users.dg

2. “Invalid file extension”

Problem: File doesn’t have .dg extension.

Solution: Rename file with correct extension.

# Rename file
mv users.txt users.dg
mv users users.dg

3. “Empty model file”

Problem: Model file is empty or has no content.

Solution: Add model content.

// Minimum valid model
model users {
  fields {
    name() string
  }

  gens {
    func name() {
      return Name()
    }
  }
}