Reusable Subflow Library

Reusable Subflow Library

Overview

The Subflow Library provides pre-built, production-ready subflows that accelerate flow development and enforce best practices. Instead of recreating common patterns, use these standardized components to build flows faster while maintaining consistency.

Benefits:

• ⚡ Faster Development: Pre-built patterns save 30-50% development time
• 🔒 Built-in Error Handling: Fault paths and logging included
• ✅ Best Practices: Bulkified, tested, and validated
• 🔄 Reusable: One subflow, many parent flows
• 📊 Maintainable: Update once, improve everywhere

Available Subflows

1. Sub_LogError

Purpose: Structured error logging for fault paths File: assets/subflows/subflow-error-logger.xml

When to Use:

• In fault paths of DML operations
• When you need to capture and track flow failures
• For production observability and debugging

Input Variables:

• varFlowName (String): Name of the calling flow
• varRecordId (String): ID of the record being processed
• varErrorMessage (String): Error message (typically $Flow.FaultMessage)

Output Variables: None

Example:

<subflows>
    <name>Log_Update_Error</name>
    <flowName>Sub_LogError</flowName>
    <inputAssignments>
        <name>varFlowName</name>
        <value>
            <stringValue>RTF_Account_UpdateIndustry</stringValue>
        </value>
    </inputAssignments>
    <inputAssignments>
        <name>varRecordId</name>
        <value>
            <elementReference>$Record.Id</elementReference>
        </value>
    </inputAssignments>
    <inputAssignments>
        <name>varErrorMessage</name>
        <value>
            <elementReference>$Flow.FaultMessage</elementReference>
        </value>
    </inputAssignments>
</subflows>

Prerequisites: Create Flow_Error_Log__c custom object with fields:

• Flow_Name__c (Text, 255)
• Record_Id__c (Text, 18)
• Error_Message__c (Long Text Area, 32,768)

Related: Error Logging Example

2. Sub_SendEmailAlert

Purpose: Standard email notifications File: assets/subflows/subflow-email-alert.xml

When to Use:

• Send notifications when certain conditions are met
• Alert users about flow completion or errors
• Standardize email formatting across flows

Input Variables:

• varEmailAddresses (String): Comma-separated email addresses
• varEmailSubject (String): Email subject line
• varEmailBody (String): Email body content

Output Variables: None

Example:

<subflows>
    <name>Notify_Manager</name>
    <flowName>Sub_SendEmailAlert</flowName>
    <inputAssignments>
        <name>varEmailAddresses</name>
        <value>
            <elementReference>$Record.Manager.Email</elementReference>
        </value>
    </inputAssignments>
    <inputAssignments>
        <name>varEmailSubject</name>
        <value>
            <stringValue>High-Value Opportunity Created</stringValue>
        </value>
    </inputAssignments>
    <inputAssignments>
        <name>varEmailBody</name>
        <value>
            <stringValue>A new opportunity worth {!$Record.Amount} has been created.</stringValue>
        </value>
    </inputAssignments>
</subflows>

Best Practices:

• Use formula fields or text templates to build dynamic email bodies
• Consider using email templates instead for complex HTML emails
• Validate email addresses before passing to subflow

3. Sub_ValidateRecord

Purpose: Common validation patterns File: assets/subflows/subflow-record-validator.xml

When to Use:

• Validate required fields before DML operations
• Check business rules before proceeding
• Return validation status to parent flow

Input Variables:

• varFieldValue (String): Field value to validate

Output Variables:

• varIsValid (Boolean): true if validation passed, false otherwise
• varValidationMessage (String): Validation result message

Example:

<subflows>
    <name>Validate_Industry</name>
    <flowName>Sub_ValidateRecord</flowName>
    <inputAssignments>
        <name>varFieldValue</name>
        <value>
            <elementReference>$Record.Industry</elementReference>
        </value>
    </inputAssignments>
    <storeOutputAutomatically>true</storeOutputAutomatically>
</subflows>

<!-- Decision based on validation result -->
<decisions>
    <name>Check_Validation</name>
    <rules>
        <name>Valid</name>
        <conditions>
            <leftValueReference>Validate_Industry.varIsValid</leftValueReference>
            <operator>EqualTo</operator>
            <rightValue>
                <booleanValue>true</booleanValue>
            </rightValue>
        </conditions>
        <connector>
            <targetReference>Proceed_With_Update</targetReference>
        </connector>
    </rules>
    <defaultConnector>
        <targetReference>Show_Error_Screen</targetReference>
    </defaultConnector>
</decisions>

Extension: Customize the validation logic in the subflow for your specific needs:

• Add more complex rules (regex, format checks)
• Validate multiple fields
• Check against external systems

4. Sub_UpdateRelatedRecords

Purpose: Bulk update pattern with error handling File: assets/subflows/subflow-bulk-updater.xml

When to Use:

• Update collections of related records
• Maintain bulkification best practices
• Centralize common update logic

Input Variables:

• colRecordsToUpdate (SObject Collection): Collection of records to update
• varNewValue (String): New value to assign (customize for your field type)

Output Variables: None

Example:

<!-- First, collect records in a loop -->
<loops>
    <name>Loop_Through_Contacts</name>
    <collectionReference>Get_Related_Contacts</collectionReference>
    <iterationOrder>Asc</iterationOrder>
    <nextValueConnector>
        <targetReference>Add_To_Collection</targetReference>
    </nextValueConnector>
    <noMoreValuesConnector>
        <targetReference>Call_Bulk_Updater</targetReference>
    </noMoreValuesConnector>
</loops>

<assignments>
    <name>Add_To_Collection</name>
    <assignmentItems>
        <assignToReference>colContactsToUpdate</assignToReference>
        <operator>Add</operator>
        <value>
            <elementReference>Loop_Through_Contacts</elementReference>
        </value>
    </assignmentItems>
    <connector>
        <targetReference>Loop_Through_Contacts</targetReference>
    </connector>
</assignments>

<!-- Then, call subflow OUTSIDE the loop -->
<subflows>
    <name>Call_Bulk_Updater</name>
    <flowName>Sub_UpdateRelatedRecords</flowName>
    <inputAssignments>
        <name>colRecordsToUpdate</name>
        <value>
            <elementReference>colContactsToUpdate</elementReference>
        </value>
    </inputAssignments>
    <inputAssignments>
        <name>varNewValue</name>
        <value>
            <elementReference>$Record.Industry</elementReference>
        </value>
    </inputAssignments>
</subflows>

Key Pattern: ✅ Correct: Loop → Add to Collection → (Outside Loop) → Call Subflow with Collection ❌ Incorrect: Loop → Call Subflow → (DML in loop!)

5. Sub_QueryRecordsWithRetry

Purpose: Query with built-in error handling File: assets/subflows/subflow-query-with-retry.xml

When to Use:

• Query related records with fault handling
• Standardize query patterns
• Log query failures for troubleshooting

Input Variables:

• varAccountId (String): Filter criteria (customize for your query)

Output Variables:

• Automatically stores query results (use storeOutputAutomatically="true")

Example:

<subflows>
    <name>Get_Related_Contacts</name>
    <flowName>Sub_QueryRecordsWithRetry</flowName>
    <inputAssignments>
        <name>varAccountId</name>
        <value>
            <elementReference>$Record.Id</elementReference>
        </value>
    </inputAssignments>
    <storeOutputAutomatically>true</storeOutputAutomatically>
</subflows>

<!-- Access query results -->
<decisions>
    <name>Check_Results</name>
    <rules>
        <name>Contacts_Found</name>
        <conditions>
            <leftValueReference>Get_Related_Contacts</leftValueReference>
            <operator>IsNull</operator>
            <rightValue>
                <booleanValue>false</booleanValue>
            </rightValue>
        </conditions>
        <connector>
            <targetReference>Process_Contacts</targetReference>
        </connector>
    </rules>
    <defaultConnector>
        <targetReference>No_Contacts_Path</targetReference>
    </defaultConnector>
</decisions>

Customization: Modify the query filters in the template for your specific object and criteria.

Deployment Guide

Step 1: Deploy Subflows to Your Org

# Deploy all subflows at once
sf project deploy start \
  --source-dir assets/subflows/ \
  --target-org myorg

# Or deploy individually
sf project deploy start \
  --source-dir assets/subflows/subflow-error-logger.xml \
  --target-org myorg

Step 2: Activate Subflows

1. Navigate to Setup → Flows
2. Find each subflow (Sub_LogError, Sub_SendEmailAlert, etc.)
3. Click Activate

⚠️ Important: Deploy Sub_LogError first if other subflows use it for error handling.

Step 3: Create Required Custom Objects

For Sub_LogError, create the Flow_Error_Log__c object:

# Using Salesforce CLI
sf data create record \
  --sobject CustomObject \
  --values "FullName=Flow_Error_Log__c Label='Flow Error Log' PluralLabel='Flow Error Logs'"

Or manually in Setup → Object Manager → Create → Custom Object.

Usage Patterns

Pattern 1: Orchestrated Error Handling

Use Sub_LogError consistently across all flows:

Parent Flow
├── DML Operation 1 → [Fault] → Sub_LogError
├── DML Operation 2 → [Fault] → Sub_LogError
└── Subflow Call → [Fault] → Sub_LogError

Pattern 2: Modular Notifications

Centralize all email logic in Sub_SendEmailAlert:

Record-Triggered Flow
├── Decision: High Value?
│   ├── Yes → Sub_SendEmailAlert(Manager)
│   └── No → End
└── Decision: Overdue?
    ├── Yes → Sub_SendEmailAlert(Owner)
    └── No → End

Pattern 3: Validation Pipeline

Chain validation subflows before DML:

Screen Flow
├── Sub_ValidateRecord(Required Fields)
│   └── Invalid? → Show Error
├── Sub_ValidateRecord(Business Rules)
│   └── Invalid? → Show Error
└── All Valid → Create Record

Best Practices

✅ DO:

1. Deploy Once, Reference Everywhere: Activate subflows in your org, then reference them in multiple parent flows
2. Use Naming Conventions: Start subflow names with Sub_ for easy identification
3. Add Fault Paths: Connect all DML operations in subflows to error handlers
4. Document Inputs/Outputs: Use clear variable names (varFieldName, colRecordCollection)
5. Version Control: Track subflow changes and test before updating active versions

❌ DON'T:

1. Don't Copy-Paste Subflows: Reference the deployed subflow instead of duplicating logic
2. Don't Skip Error Handling: All subflows should handle their own errors gracefully
3. Don't Hardcode Values: Use input variables for flexibility
4. Don't Create DML in Loops: Use Sub_UpdateRelatedRecords pattern for bulk operations
5. Don't Forget Testing: Test subflows independently before using in parent flows

Testing Your Subflows

Unit Testing Individual Subflows

1. Create a test flow that calls the subflow
2. Pass various input combinations (valid, invalid, null)
3. Verify output variables and behavior
4. Check error logs if using Sub_LogError

# Example: Test Sub_LogError
sf data query \
  --query "SELECT Flow_Name__c, Error_Message__c FROM Flow_Error_Log__c ORDER BY CreatedDate DESC LIMIT 5" \
  --target-org myorg

Integration Testing in Parent Flows

1. Use subflows in record-triggered flows
2. Test with bulk data (200+ records)
3. Verify subflow doesn't cause governor limit errors
4. Check execution time in debug logs

Customization Guide

Extending Subflows

All subflows are templates—customize for your needs:

1. Clone the subflow: Create a copy (e.g., Sub_LogError_WithEmail)
2. Add custom logic: Extend functionality while keeping core pattern
3. Maintain naming convention: Keep Sub_ prefix for discoverability

Example: Enhanced Error Logger

Extend Sub_LogError to send Platform Events:

<!-- Add to subflow after Create_Error_Log -->
<recordCreates>
    <name>Publish_Error_Event</name>
    <object>Flow_Error__e</object>
    <inputAssignments>
        <field>Flow_Name__c</field>
        <value>
            <elementReference>varFlowName</elementReference>
        </value>
    </inputAssignments>
    <!-- Real-time error monitoring -->
</recordCreates>

Performance Considerations

Governor Limits

• Subflow Depth: Maximum 50 levels of nested subflows (avoid deep nesting)
• DML Statements: Each subflow DML counts toward 150 limit
• SOQL Queries: Each subflow query counts toward 100 limit

Optimization Tips

1. Batch Operations: Use Sub_UpdateRelatedRecords for bulk updates
2. Minimize Subflow Calls: Call once with collections vs. multiple times with single records
3. Cache Results: Store subflow outputs in variables to avoid repeated calls

Troubleshooting

"Subflow not found" Error

• ✅ Verify subflow is activated in target org
• ✅ Check API name matches exactly (Sub_LogError, not Sub_Log_Error)
• ✅ Deploy subflow before deploying parent flow

"Input variable not found" Error

• ✅ Verify variable names match subflow definition
• ✅ Check variable data types (String vs. SObject Collection)
• ✅ Ensure required inputs are provided

Performance Issues

• ✅ Check debug logs for subflow execution time
• ✅ Avoid calling subflows inside loops
• ✅ Use bulk operations with collections

Version History

Related Documentation

• Error Logging Example - Detailed Sub_LogError usage
• Orchestration Guide - Parent-child flow patterns
• Flow Best Practices - Flow guidelines and security

Support

For issues or questions:

1. Check subflow XML for correct variable names and types
2. Test subflow independently before using in parent flow
3. Review error logs in Flow_Error_Log__c (if using Sub_LogError)
4. Check debug logs for detailed execution information

Happy flow building! 🚀