Google App Engine to Azure App Service Migration
Detailed guidance for migrating Google App Engine applications to Azure App Service.
Service Mapping
| GCP Service | Azure Equivalent |
|---|---|
| App Engine (Standard) | Azure App Service (Standard/Premium plan) |
| App Engine (Flex) | Azure App Service (Premium v3) or Container Apps |
| App Engine Services | App Service apps (one per service) |
app.yaml | azure.yaml + Bicep |
| Datastore / Firestore | Azure Cosmos DB |
| Cloud SQL (PostgreSQL) | Azure Database for PostgreSQL Flexible Server |
| Cloud SQL (MySQL) | Azure Database for MySQL Flexible Server |
| Cloud Storage | Azure Blob Storage |
| Cloud Tasks | Azure Service Bus / Durable Functions |
| Cloud Pub/Sub | Azure Service Bus / Event Grid |
| Memcache / Memorystore | Azure Cache for Redis |
| Cloud Scheduler | Azure Functions Timer trigger |
| Cloud CDN | Azure Front Door / Azure CDN |
| Cloud DNS | Azure DNS |
| Cloud Logging | Application Insights / Azure Monitor |
| Cloud Monitoring | Azure Monitor Metrics |
| Cloud Trace | Application Insights (distributed tracing) |
| Cloud IAM | Managed Identity + Azure RBAC |
| Cloud Build | GitHub Actions / Azure DevOps |
| Traffic Splitting | Deployment Slots (weighted routing) |
| Service Versions | Deployment Slots |
| Cloud KMS | Azure Key Vault |
| Secret Manager | Azure Key Vault |
| Cloud Endpoints | Azure API Management |
| Identity-Aware Proxy | Azure Front Door + Entra ID auth |
| VPC Connector | VNet Integration |
Standard vs Flex → App Service Plan Mapping
| App Engine Tier | App Service Equivalent | Notes |
|---|---|---|
| Standard (F1 instance) | Free (F1) | Dev/test only |
| Standard (B1/B2) | Basic (B1/B2) | Low-traffic apps |
| Standard (auto-scaling) | Standard (S1-S3) | Auto-scale, slots |
| Flex (custom runtime) | Premium v3 (P1v3-P3v3) | Custom containers |
| Flex (high-memory) | Premium v3 (P3v3) | Up to 32 GB RAM |
app.yaml → azure.yaml + Bicep
App Engine Configuration Mapping
app.yaml Field | Azure Equivalent | Implementation |
|---|---|---|
runtime: python312 | Runtime stack: Python 3.12 | Bicep siteConfig.linuxFxVersion |
instance_class: F2 | App Service Plan SKU | Bicep sku.name |
automatic_scaling | Autoscale settings | Bicep Microsoft.Insights/autoscalesettings |
env_variables | App Settings | Bicep siteConfig.appSettings |
handlers (URL routing) | App Service path mappings / Front Door | Route rules |
entrypoint | Startup command | az webapp config set --startup-file |
vpc_access_connector | VNet Integration | Bicep virtualNetworkSubnetId |
inbound_services: [warmup] | Always On | Bicep siteConfig.alwaysOn: true |
Example: app.yaml → Bicep
# app.yaml (GCP)
runtime: python312
instance_class: F2
automatic_scaling:
min_instances: 1
max_instances: 10
env_variables:
DATABASE_URL: "postgres://..."// Bicep equivalent
resource appServicePlan 'Microsoft.Web/serverfarms@2023-12-01' = {
sku: { name: 'S2', capacity: 1 }
properties: { reserved: true }
}
resource webApp 'Microsoft.Web/sites@2023-12-01' = {
properties: {
siteConfig: {
linuxFxVersion: 'PYTHON|3.12'
alwaysOn: true
appSettings: [
{ name: 'PGHOST', value: postgresServer.properties.fullyQualifiedDomainName }
]
}
}
}Datastore / Firestore → Cosmos DB
| Datastore Feature | Cosmos DB Equivalent |
|---|---|
| Entity / Document | Item |
| Kind / Collection | Container |
| Namespace | Database |
| Key / ID | Partition key + ID |
| Ancestor queries | Hierarchical partition keys |
| Eventual consistency | Session or Eventual consistency |
| Strong consistency | Strong consistency |
ndb / google.cloud.datastore | @azure/cosmos SDK |
💡 Tip: Use Cosmos DB for NoSQL API for the closest mapping from Datastore. Use Cosmos DB for MongoDB API if the app already uses MongoDB-compatible patterns.
Cloud Tasks → Service Bus / Durable Functions
| Cloud Tasks Feature | Azure Equivalent |
|---|---|
| HTTP target tasks | Service Bus + Azure Functions |
| App Engine target tasks | Service Bus + WebJobs |
| Task scheduling (delayed) | Service Bus scheduled messages |
| Task retry / dead-letter | Service Bus retry + dead-letter queue |
| Rate limiting | Service Bus message throttling |
| Task orchestration | Durable Functions (fan-out/fan-in) |
Traffic Splitting → Deployment Slots
| App Engine Feature | Azure Equivalent |
|---|---|
| Version traffic splitting (%) | Slot traffic routing (%) |
| Canary deployment | Slot with low traffic % |
| A/B testing | Slot traffic routing |
| Version rollback | Slot swap (revert) |
| Gradual rollout | Increase slot traffic % incrementally |
| Warmup requests | Slot warm-up (pre-swap) |
// Configure traffic routing: 90% production, 10% staging
resource siteConfig 'Microsoft.Web/sites/config@2023-12-01' = {
name: 'web'
properties: {
experiments: {
rampUpRules: [{
actionHostName: '${webApp.name}-staging.azurewebsites.net'
reroutePercentage: 10
name: 'staging'
}]
}
}
}Memcache → Azure Cache for Redis
| Memcache Feature | Azure Cache for Redis |
|---|---|
memcache.get() / set() | redis.get() / redis.set() |
| Shared memcache | Azure Cache for Redis (Basic) |
| Dedicated memcache | Azure Cache for Redis (Standard/Premium) |
| Session store | Redis session store |
| Cache expiry | Redis TTL |
Environment Variables Migration
| Source | Target | Notes |
|---|---|---|
app.yaml env_variables | App Settings | Non-sensitive config |
| Secret Manager refs | Key Vault references | @Microsoft.KeyVault(SecretUri=...) |
| Runtime env (auto-injected) | App Settings | Map GAE-specific vars |
GAE_APPLICATION | WEBSITE_SITE_NAME | Auto-injected by App Service |
PORT | PORT | Auto-injected by App Service |
GOOGLE_CLOUD_PROJECT | (no equivalent) | GCP project IDs identify a runtime environment; Azure subscription IDs are a tooling/billing context, not a runtime equivalent. Use App Service WEBSITE_RESOURCE_GROUP or rely on DefaultAzureCredential to discover the subscription at runtime if needed. |
CI/CD Migration
| Cloud Build / gcloud | Azure Equivalent |
|---|---|
gcloud app deploy | az webapp deploy or azd deploy |
cloudbuild.yaml | .github/workflows/deploy.yml |
| Cloud Build triggers | GitHub Actions triggers |
| Artifact Registry | Azure Container Registry |
gcloud app versions | Deployment slots |