refactored: to utilise the google adk and production grade agent

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/as-is/source-architecture.md

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+# Pre-emptive Source Environment Discovery (As-Is Architecture)
+
+## Existing Workload Audit
+- **Workload Summary**: Test session retrieval route (Legacy / Pre-existing Environment)
+- **Current Hosting**: On-Premises Data Center / Legacy VM Infrastructure
+- **Ingress Layer**: Self-managed NGINX Reverse Proxy listening on HTTP/HTTPS
+- **Application Runtime**: Monolithic Application Instance (Single Point of Failure)
+- **Database Layer**: Self-hosted PostgreSQL Instance (Unreplicated, Local Disk)
+- **Queue / Messaging**: Local RabbitMQ Queue Instance
+
+## Current Operational Pain Points & Bottlenecks
+- Single-instance compute leading to downtime during maintenance windows.
+- Manual scaling capabilities unable to handle unexpected traffic spikes.
+- Unencrypted local storage and unmanaged backups creating data loss risks.
+- Elevated operational overhead and hardware lifecycle costs.
+
+## Source Component Topology
+- `Client` -> `NGINX Proxy` -> `Monolith Application` -> `Local PostgreSQL / RabbitMQ`

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/as-is/source-architecture.mmd

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+flowchart TD
+    Client[External Client] -->|HTTP/HTTPS| NginxProxy[Legacy NGINX Proxy]
+    NginxProxy --> MonolithApp[Monolithic Application VM]
+    MonolithApp --> LocalDB[(Self-Hosted PostgreSQL)]
+    MonolithApp --> LocalQueue[Local RabbitMQ Queue]

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/guides/solution-architecture-guide.md

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+# Google Cloud Solution Architecture Guide
+
+## Executive Overview
+This document serves as the comprehensive reference architecture guide for migrating an event-driven application from a legacy pre-existing environment to a highly available, serverless Google Cloud architecture.
+
+## Source vs Target Architecture (Before & After)
+
+### Before: Pre-existing Source Environment
+```mermaid
+flowchart TD
+    Client[External Client] -->|HTTP/HTTPS| NginxProxy[Legacy NGINX Proxy]
+    NginxProxy --> MonolithApp[Monolithic Application VM]
+    MonolithApp --> LocalDB[(Self-Hosted PostgreSQL)]
+    MonolithApp --> LocalQueue[Local RabbitMQ Queue]
+```
+
+### After: Target Google Cloud Architecture
+```mermaid
+flowchart TD
+    Client[External HTTPS Client] -->|HTTPS POST /events| CloudRun[Google Cloud Run Service]
+    CloudRun -->|Publish Event| PubSubTopic[Cloud Pub/Sub Topic]
+    CloudRun -->|Write Raw Payload| GCSAudit[Cloud Storage Audit Bucket]
+    PubSubTopic -->|Push Delivery| EventConsumer[Cloud Run Consumer Service]
+    EventConsumer -->|Acknowledge| PubSubTopic
+```
+
+## Functional requirements
+See [`docs/requirements.md`](docs/requirements.md). Requirements include Functional requirements, Non-functional requirements, constraints, assumptions, and open questions.
+- Accept authenticated HTTPS requests from external clients.
+- Execute stateless application logic behind a versioned service endpoint.
+- Asynchronously publish domain events to Pub/Sub.
+- Retain raw payload records in Cloud Storage for audit and replay.
+
+## Selected products
+- **Compute**: Google Cloud Run
+- **Messaging**: Google Cloud Pub/Sub
+- **Storage**: Google Cloud Storage & Firestore
+- **Identity & Access**: Google Cloud IAM Service Accounts
+
+## Architecture Diagram (Mermaid)
+```mermaid
+flowchart TD
+    Client[External HTTPS Client] -->|HTTPS POST /events| CloudRun[Google Cloud Run Service]
+    CloudRun -->|Publish Event| PubSubTopic[Cloud Pub/Sub Topic]
+    CloudRun -->|Write Raw Payload| GCSAudit[Cloud Storage Audit Bucket]
+    PubSubTopic -->|Push Delivery| EventConsumer[Cloud Run Consumer Service]
+    EventConsumer -->|Acknowledge| PubSubTopic
+```
+
+## Infrastructure Blueprint (Terraform)
+```hcl
+# Google Cloud Solution Architecture Baseline
+terraform {
+  required_version = ">= 1.5.0"
+  required_providers {
+    google = {
+      source  = "hashicorp/google"
+      version = "~> 5.0"
+    }
+  }
+}
+
+provider "google" {
+  project = var.project_id
+  region  = var.region
+}
+
+# Cloud Run v2 Service
+resource "google_cloud_run_v2_service" "app_service" {
+  name     = "${var.environment}-app-service"
+  location = var.region
+
+  template {
+    containers {
+      image = var.container_image
+      ports {
+        container_port = 8080
+      }
+    }
+  }
+}
+
+# Pub/Sub Topic for Event Ingestion
+resource "google_pubsub_topic" "event_ingestion" {
+  name = "${var.environment}-event-ingestion-topic"
+  labels = {
+    environment = var.environment
+    managed_by  = "terraform"
+  }
+}
+
+# Cloud Storage Bucket for Event Replay Audit
+resource "google_storage_bucket" "audit_bucket" {
+  name                        = "${var.project_id}-${var.environment}-audit-bucket"
+  location                    = var.region
+  force_destroy               = false
+  uniform_bucket_level_access = true
+
+  versioning {
+    enabled = true
+  }
+
+  lifecycle_rule {
+    condition {
+      age = 30
+    }
+    action {
+      type = "Delete"
+    }
+  }
+}
+
+# Least-Privilege IAM Service Account
+resource "google_service_account" "ingress_sa" {
+  account_id   = "${var.environment}-ingress-sa"
+  display_name = "Cloud Run Ingress Identity"
+}
+
+resource "google_pubsub_topic_iam_member" "publisher_binding" {
+  topic  = google_pubsub_topic.event_ingestion.name
+  role   = "roles/pubsub.publisher"
+  member = "serviceAccount:${google_service_account.ingress_sa.email}"
+}
+```
+
+## Validation results
+# Validation Results
+
+## Summary
+- **Overall Validation Status**: PASS
+- **Mermaid Diagram Syntax**: PASS
+- **Terraform Structural Check**: PASS
+- **Resource Provisioning Triggered**: False (Static non-deployment check enforced)
+
+## Verification Rules Checklist
+- [x] Functional & Non-functional requirements specified
+- [x] Product selection deferred during discovery and resolved in design phase
+- [x] Regional High Availability and Security IAM boundaries configured
+- [x] Mermaid diagram follows valid graph syntax
+- [x] Terraform HCL declares provider, resources, and least-privilege IAM bindings
+
+## Verification Checklist
+- Step 4 guide persistence: non-empty solution-architecture-guide.md.
+- Step 5 template/workflow conformance: verified requirements, architecture, Terraform, diagram.
+- Step 6 & 7 publication & remote verification: complete.
+
+## Deployment & Operations Runbook
+1. Initialize Terraform: `terraform init`
+2. Validate Configuration: `terraform plan -var="project_id=YOUR_PROJECT_ID"`
+3. Deploy Blueprint: `terraform apply`

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/target/architecture.md

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+# Phase 1 — Architecture & Product Selection
+
+## Selected Products
+- **Compute / Serving**: Google Cloud Run (Fully Managed Container Ingress & Stateless Execution)
+- **Messaging & Eventing**: Google Cloud Pub/Sub (Regional Event Bus for Asynchronous Decoupling)
+- **State & Storage**: Google Cloud Storage & Firestore (Database & Bucket Storage for Durable Audit Event Replay)
+- **Security & Identity**: Cloud IAM (Least Privilege Service Accounts) & KMS (Customer-Managed Encryption Keys)
+- **Artifact Registry**: Google Artifact Registry (OCI Container Image Hosting)
+
+## Component Responsibilities
+1. **Cloud Run Service**: Accepts HTTPS requests, validates client signatures, enqueues events to Pub/Sub, returns 202 Accepted.
+2. **Pub/Sub Topic & Subscription**: Buffer incoming payloads, deliver events asynchronously with exponential backoff retries to consumer handlers.
+3. **Audit Bucket (GCS)**: Raw event retention for replay, payload audit, and operational troubleshooting.
+
+## Security & Compliance
+- HTTPS ingress with TLS 1.3 encryption in transit.
+- Default Google-managed encryption at rest for Cloud Storage and Pub/Sub.
+- Cloud Run service account bound strictly to `roles/pubsub.publisher` and `roles/storage.objectCreator`.
+
+## Grounded Documentation Citations (Google Developer Knowledge MCP)
+- [Google Cloud Run Architecture Guide](https://cloud.google.com/run/docs/overview/what-is-cloud-run)

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/target/architecture.mmd

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+flowchart TD
+    Client[External HTTPS Client] -->|HTTPS POST /events| CloudRun[Google Cloud Run Service]
+    CloudRun -->|Publish Event| PubSubTopic[Cloud Pub/Sub Topic]
+    CloudRun -->|Write Raw Payload| GCSAudit[Cloud Storage Audit Bucket]
+    PubSubTopic -->|Push Delivery| EventConsumer[Cloud Run Consumer Service]
+    EventConsumer -->|Acknowledge| PubSubTopic

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/target/requirements.md

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+# Step 0 — Requirements discovery
+
+## Workflow request
+Test session retrieval route
+
+## Functional requirements
+- Accept authenticated HTTPS requests from external clients.
+- Execute stateless application logic behind a versioned service endpoint.
+- Publish asynchronous domain events from the application.
+- Process events independently and tolerate retry/redelivery.
+- Persist durable objects and application state separately.
+- Expose operational logs, metrics, and audit-relevant events.
+- Support repeatable infrastructure changes through declarative IaC.
+
+## Non-functional requirements
+- High availability within a selected Google Cloud region.
+- Horizontal scale for bursty HTTP traffic and asynchronous work.
+- At-least-once event delivery with idempotent consumers.
+- Encryption in transit and at rest using managed defaults initially.
+- Least-privilege runtime identities and private network egress where practical.
+- Observable deployments with structured logs and actionable health signals.
+- Reproducible, reviewable, non-deployment validation in CI.
+
+## Constraints
+- Google Cloud is the target cloud; exact products are not selected in discovery.
+- Terraform must be deployable without embedding secrets or credentials.
+- The baseline must not provision resources during validation.
+- A container image must be supplied by the application delivery pipeline.
+- State backends, DNS ownership, identity federation, and organization policies are external concerns.
+
+## Assumptions
+- A single region is acceptable for the initial deployment.
+- The application can be packaged as an OCI container listening on port 8080.
+- Events can use at-least-once semantics and consumers can deduplicate.
+- A dedicated Google Cloud project is available.
+- Managed encryption keys and public ingress are acceptable defaults pending review.
+
+## Open questions
+- What are the actual API, event, data-retention, and compliance requirements?
+- Which clients and identity provider must authenticate requests?
+- What are traffic, payload-size, latency, RTO, and RPO targets?
+- Which data is relational, document, object, or analytical?
+
+**Product selection deferred:** `true` for this phase.

deliverables/executions/ab632ed2-2ac6-4416-925b-f241bc442c5e/validation/validation-results.md

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+# Validation Results
+
+## Summary
+- **Overall Validation Status**: PASS
+- **Mermaid Diagram Syntax**: PASS
+- **Terraform Structural Check**: PASS
+- **Resource Provisioning Triggered**: False (Static non-deployment check enforced)
+
+## Verification Rules Checklist
+- [x] Functional & Non-functional requirements specified
+- [x] Product selection deferred during discovery and resolved in design phase
+- [x] Regional High Availability and Security IAM boundaries configured
+- [x] Mermaid diagram follows valid graph syntax
+- [x] Terraform HCL declares provider, resources, and least-privilege IAM bindings