feat(DATAGO-114389): PR 2: Workflow Definition Models

[efunneko]

PR 2: Workflow Definition Models

Overview

This PR introduces the Pydantic models that define the YAML schema for workflow definitions. These models provide Argo Workflows-compatible syntax with SAM extensions, enabling users to define deterministic, structured workflow DAGs.

Branch Information

• Branch Name: pr/workflows-2-models
• Target: pr/workflows-1-foundation

Files Changed

src/solace_agent_mesh/workflow/app.py

Complete workflow definition model hierarchy:

Retry & Exit Handlers

Model	Purpose
BackoffStrategy	Exponential backoff configuration for retries
RetryStrategy	Retry configuration (limit, policy, backoff)
ExitHandler	Cleanup/notification on workflow completion

Node Types

Model	Purpose
WorkflowNode	Base node class with id, type, depends_on
AgentNode	Invoke an agent with input/output schemas
ConditionalNode	Binary if/else branching
SwitchNode	Multi-way branching (first match wins)
SwitchCase	Individual case in switch node
LoopNode	While-loop iteration until condition false
MapNode	Parallel for-each iteration over items

Workflow Definition & Configuration

Model	Purpose
WorkflowDefinition	Complete workflow DAG with nodes, schemas, exit handlers
WorkflowAppConfig	App configuration extending SamAgentAppConfig
WorkflowApp	Custom App class for workflow orchestration

src/solace_agent_mesh/workflow/__init__.py

Package initialization and exports.

Key Concepts

Argo Workflows Compatibility

The models support Argo-style field names via aliases:

# Both syntaxes work:
depends_on: [step1]      # SAM style
dependencies: [step1]     # Argo style

true_branch: step2        # SAM style
trueBranch: step2         # Argo style

Node Type Summary

Type	Use Case	Key Fields
agent	Call an agent	agent_name, input, when, retry_strategy
conditional	Binary branch	condition, true_branch, false_branch
switch	Multi-way branch	cases[], default
loop	While iteration	node, condition, max_iterations
map	For-each parallel	items, node, concurrency_limit

DAG Validation

WorkflowDefinition.validate_dag_structure() ensures:

• All node references are valid
• Branch targets depend on their parent node
• Exit handler references exist
• No configuration contradictions

Template Expression Syntax

Input mappings use template expressions:

input:
  query: "{{workflow.input.search_term}}"
  data: "{{previous_node.output.results}}"

[efunneko]

Closing as part of stacked PR cleanup. This PR has been reviewed and approved. Any follow-up items have been tracked in Jira.