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Bilko HR e-Račun Archive — GCS→Azure Blob Migration (2026-06-22)

Bilko HR e-Račun Archive — GCS→Azure Blob Migration (2026-06-22)

Overview

MC: #104172 T3 (build) + T4b (deploy) + T5 (verify) + T6 (docs, this page)

Date: 2026-06-22

Status: Deployed to stage, live verified with real sveRačun TEST API

Root cause: Bilko's HR e-invoice archive used Google Cloud Storage (GCS) in project tribal-sign-487920-k0. That GCP project billing was killed 2026-06-14, making all GCS writes fail with HTTP 401. The archive write happens before the sveRačun API call, so HR e-invoice submit flow was completely blocked.

Solution: Migrate the archive from GCS to Azure Blob Storage (swedencentral, same region as Bilko API). Keep the same GcsArchiveClient interface for backwards compatibility, implement RealAzureBlobArchiveClient.

Architecture

Interface Contract (GcsArchiveClient)

The interface remains GcsArchiveClient (name is historical). Two implementations:

  • InMemoryGcsArchiveClient (existing) — ConcurrentHashMap, write-once, no cloud dependency. Used when DEMO_MODE=true and ARCHIVE_BACKEND is not explicitly set.
  • RealAzureBlobArchiveClient (new, MC #104172) — Azure Blob write-once via If-None-Match: * → HTTP 412 if blob exists. SHA-256 integrity check. Never logs XML bytes.

Write-Once Mechanism

The archive must be immutable. Both implementations enforce write-once:

  • InMemory: ConcurrentHashMap.putIfAbsent() — atomic write-once in memory
  • Azure Blob: BlobClient.uploadWithResponse(..., If-None-Match: *) → HTTP 201 if new, 412 if exists. Any 412 is treated as success (idempotent).

Authentication (Managed Identity)

Azure Blob uses Azure Managed Identity (user-assigned MI) for authentication:

  • MI name: mi-bilko-demo
  • Client ID: e569c4e7-59e5-40a1-9aa3-a0dba9ceb738
  • Role: Storage Blob Data Contributor on storage account stbilkohreinvoicedemo
  • The MI is attached to ACA app bilko-api-stage (and bilko-api-demo when promoted)
  • Runtime: DefaultAzureCredential binds to the MI via env var AZURE_CLIENT_ID

Environment Contract

The following env vars control archive behavior:

Env VarExampleNotes
ARCHIVE_BACKENDazure-blobSet to azure-blob to use Azure Blob. If unset, falls back to DEMO_MODE logic.
AZURE_EINVOICE_BLOB_ENDPOINThttps://stbilkohreinvoicedemo.blob.core.windows.netAzure Blob endpoint (required if ARCHIVE_BACKEND=azure-blob)
AZURE_EINVOICE_CONTAINERhr-einvoice-archiveBlob container name
AZURE_CLIENT_IDe569c4e7-59e5-40a1-9aa3-a0dba9ceb738User-assigned MI client ID (for DefaultAzureCredential)
DEMO_MODEtrueIf true and ARCHIVE_BACKEND is not set → InMemoryGcsArchiveClient

Precedence Rule (CRITICAL)

ARCHIVE_BACKEND takes precedence over DEMO_MODE.

DI binding (DI.kt lines 217-233):

val archiveBackend = System.getenv("ARCHIVE_BACKEND")
val archiveClient = when {
    archiveBackend == "azure-blob" -> RealAzureBlobArchiveClient(...)
    isDemoMode -> InMemoryGcsArchiveClient()
    else -> error("...")
}

This means: if ARCHIVE_BACKEND=azure-blob is set on stage (where DEMO_MODE=true), the Azure Blob client is selected, NOT the in-memory client.

Azure Infrastructure

Storage Account

  • Name: stbilkohreinvoicedemo
  • Resource Group: rg-bilko-demo
  • Location: swedencentral (same as ACA apps)
  • Replication: Standard_LRS
  • Container: hr-einvoice-archive
  • Blob versioning: Enabled (provides audit trail without app-level code changes)

Managed Identity

  • Name: mi-bilko-demo
  • Client ID: e569c4e7-59e5-40a1-9aa3-a0dba9ceb738
  • Role assignment: Storage Blob Data Contributor on stbilkohreinvoicedemo
  • Attached to both bilko-api-stage and bilko-api-demo

Deployment Procedure (Direct Deploy)

Context: The Azure DevOps pipeline branch policy "Bilko-CI-CD PR Validation" blocks merges to main due to flaky E2E UAT debt (MC #103954). The bypassPolicy permission is denied. Therefore, the fix was deployed DIRECTLY to stage using Azure CLI (az acr build + az containerapp update).

Steps

  1. ACR build: az acr build -r bilkodemo -t bilko-api:stage-{SHA} --platform linux/amd64 -f apps/api/Dockerfile.web apps/api/
  2. ACA update: az containerapp update -n bilko-api-stage -g rg-bilko-demo --image bilkodemo.azurecr.io/bilko-api:stage-{SHA} + 4 new env vars (ARCHIVE_BACKEND, AZURE_EINVOICE_BLOB_ENDPOINT, AZURE_EINVOICE_CONTAINER, AZURE_CLIENT_ID)
  3. Revision: New revision bilko-api-stage--0000026 created, serving 100% traffic
  4. Health check: curl -s https://bilko-api-stage.purplebeach-f004d490.swedencentral.azurecontainerapps.io/api/v1/health → HTTP 200

Branch: feat/azure-blob-archive-104172 on azdo remote (PR #16 remains open for future merge when CI gate is resolved)

Commit: e6100cf1223c345678856e5cf89512704528c3f6

Image: bilkodemo.azurecr.io/bilko-api:stage-e6100cf1 (digest: sha256:03aeda482ed311ebf15b54a27c4afaee749b556bc13b5cf1f10ff28b851d19b8)

Flyway Migration GOTCHA

Bilko API does NOT auto-apply Flyway migrations on startup.

Flyway's filesystem scanner detects 0 migrations at app boot (known issue: 98 SQL files detected but not resolved by the classpath resolver → "no migration could be resolved" → app continues without applying migrations).

The migration V99 (issuer config seed) was applied manually via direct psql connection to bilko-demo-pg.postgres.database.azure.com:

psql "host=bilko-demo-pg.postgres.database.azure.com port=5432 dbname=bilko user=bilko_admin sslmode=require" -f apps/api/src/main/resources/db/migration/V99__seed_hr_einvoice_issuer_config_demo.sql

V99 registered in flyway_schema_history with success=true. Two rows seeded:

  • HR demo org (00000000-0000-0029-c000-000000000001): enabled=false, DIRECT, test.sveracun.hr
  • E2E test org (1f9811d2-af38-482d-91d9-229e1acbb37e): enabled=false, DIRECT, test.sveracun.hr

In CI/CD pipeline context: The Azure DevOps pipeline has a dedicated Flyway_Migrate stage that applies migrations. For direct deploys (bypassing CI), migrations must be applied manually.

Live Proof (T5 Verification)

Test: Submit a real HR e-invoice to sveRačun TEST API via stage.

  1. Issuer config enabled: UPDATE hr_einvoice_issuer_config SET enabled = TRUE WHERE org_id = '00000000-0000-0029-c000-000000000001' (HR demo org only, not all orgs)
  2. Submit: POST /api/v1/invoices/{invoice_id}/submit-to-sveracun (invoice INV-HR-2026-001, EUR 3000.00)
  3. Result: HTTP 200, submissionId: a3b0234b-9a6e-4c60-8368-b51da030a0f2, documentId: 6a390b5faf982834ab4306fb (real sveRačun TEST document ID, not mock)
  4. Azure Blob written: az storage blob list --account-name stbilkohreinvoicedemo --container-name hr-einvoice-archive → blob 00000000-0000-0029-c000-000000000001/2026/2026-000001/a3b0234b-9a6e-4c60-8368-b51da030a0f2.xml (5960 bytes, contentType=application/xml)

SVERACUN_HR_LIVE stayed false (confirmed via az containerapp show env check). The sveRačun call was made to TEST API (https://test.sveracun.hr/api), not live production.

PROD 11-Year WORM/Immutable Retention (Future)

Croatian law requires e-invoice archives to be retained for 11 years with immutable (WORM) protection. The current Azure Blob configuration has versioning enabled, but does NOT have time-based retention policy or legal hold.

This is a separate follow-on task (not in MC #104172 scope). Before Bilko HR goes live to paying customers:

  • Create a separate storage account for production HR archive (e.g., stbilkohrinvoiceprod)
  • Enable immutability policy: time-based retention 11 years + legal hold
  • Wire production API (bilko-api-demo when promoted to prod) to the new account
  • Document the retention policy in Bilko compliance docs

Evidence Bundle

  • Verification report: /tmp/evidence-104172/verification.md
  • T4b direct deploy: /tmp/evidence-104172/t4b-direct-deploy.md
  • T5 live proof: /tmp/evidence-104172/t5-proveo-live.md
  • GOTCHA doc: /tmp/evidence-104172/GOTCHA-104172.md

References

  • MC #104172: Parent task (Bilko HR e-invoice GCS→Azure Blob migration)
  • ADR-020: Kotlin/Ktor backend canonical
  • DI.kt: apps/api/src/main/kotlin/no/alai/bilko/plugins/DI.kt (lines 217-233: archive client binding)
  • RealAzureBlobArchiveClient: apps/api/src/main/kotlin/no/alai/bilko/country/hr/GcsArchiveClient.kt (lines 135-203)
  • V99 migration: apps/api/src/main/resources/db/migration/V99__seed_hr_einvoice_issuer_config_demo.sql
  • BookStack (DEPLOY-MAP): Bilko Deploy Map

Authored by: Skillforge (ALAI Holding AS documentation team)
Date: 2026-06-22
MC: #104172 T6

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