Migrate Workflow Metrics to Prometheus Histograms #82

Parent Issue

Part of #80 - Epic: Consolidate All Monitoring Systems into Prometheus + Grafana

Current State

src/metrics/workflow_metrics.py collects:

• Workflow execution duration
• Step-by-step timings
• Success/failure rates per complexity
• Agent usage counts
• Error tracking per workflow
• Resource usage snapshots
• Approval wait times

Data stored in-memory with max 10,000 metrics history.

Goal

Export workflow metrics to Prometheus using histograms and counters for percentile calculations and trend analysis.

Implementation

1. Add Prometheus Metrics

# Workflow execution metrics
autobot_workflow_duration_seconds = Histogram(
    'autobot_workflow_duration_seconds',
    'Workflow execution duration',
    ['workflow_type', 'complexity'],
    buckets=[0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 30.0, 60.0, 120.0]
)

autobot_workflow_total = Counter(
    'autobot_workflow_total',
    'Total workflows executed',
    ['workflow_type', 'status']  # status: success, failure, timeout
)

autobot_workflow_steps_total = Counter(
    'autobot_workflow_steps_total',
    'Total workflow steps executed',
    ['step_type']
)

# Agent usage
autobot_agent_usage_total = Counter(
    'autobot_agent_usage_total',
    'Agent usage count',
    ['agent_type']
)

# Approval metrics
autobot_approval_wait_seconds = Histogram(
    'autobot_approval_wait_seconds',
    'Time waiting for approvals',
    buckets=[1, 5, 10, 30, 60, 120, 300]
)

2. Integration Points

• Hook into WorkflowMetricsCollector.record_workflow_completion()
• Update Prometheus metrics in real-time
• Maintain in-memory buffer for backward compatibility

3. Benefits

• Automatic percentile calculations (p50, p95, p99)
• Long-term trend analysis
• Alerting on slow workflows via AlertManager

Acceptance Criteria

• Workflow duration tracked as histogram
• Success/failure rates as counters with labels
• Agent usage tracked per agent type
• Step timings aggregated properly
• Grafana can show workflow performance trends
• Alerting possible on workflow duration thresholds

Files to Modify

• src/monitoring/prometheus_metrics.py - Add workflow metric definitions
• src/metrics/workflow_metrics.py - Integrate Prometheus export
• src/core/workflow_engine.py - Ensure metrics are emitted

Labels: enhancement, monitoring, metrics