dbt Mesh PoC — Microsoft Fabric (dbt Cloud variant)

A multi-country dbt Mesh implementation on Microsoft Fabric, demonstrating cross-project, multi-domain data governance. Three dbt projects — Italy, Switzerland, and a Global aggregation layer — form a mesh where the Global project consumes the public gold models of each country project.

Two implementation variants

This project is maintained in two parallel variants, one per branch, so the same data model can be run on either runtime:

Branch	Runtime	Cross-project mechanism	Italy adapter
main-core	dbt-core (open-source CLI)	dbt-loom resolves cross-project refs from local manifests	dbt-fabricspark (Spark/Livy on Lakehouses)
main-cloud (this branch)	dbt Cloud	native dbt Mesh — dependencies.yml + ref('project','model')	dbt-fabric (T-SQL on Warehouses)

Why Italy was refactored: dbt Cloud does not yet support the dbt-fabricspark adapter. To run the full mesh on dbt Cloud, the Italy project (dbt_poc_ita) was refactored from Spark SQL on Lakehouses to T-SQL on Fabric Warehouses using the dbt-fabric adapter — so all three projects now use a single, dbt-Cloud-supported adapter.

Overview

This branch uses native dbt Mesh: the Global project declares its upstream projects in dependencies.yml and references their public models with {{ ref('dbt_poc_ita', '...') }} / {{ ref('dbt_poc_che', '...') }}. dbt Cloud resolves these cross-project references automatically — no dbt-loom and no OneLake shortcuts are required.

Project	Country	Adapter	Storage	Domains
dbt_poc_ita	Italy	dbt-fabric (T-SQL/TDS)	Warehouses silver_wh_ita / gold_wh_ita (Bronze stays Lakehouse bronze_lh_ita)	Sales, Finance
dbt_poc_che	Switzerland	dbt-fabric (T-SQL/TDS)	Warehouses (Bronze/Silver/Gold)	Sales, Finance
dbt_poc_glb	Global	dbt-fabric (T-SQL/TDS)	Warehouses (Gold Sales, Gold Finance)	Sales, Finance

Architecture

dbt_poc_ita (Italy)          dbt_poc_che (Switzerland)
  Bronze LH                    Bronze WH
      ↓                            ↓
  Silver WH                    Silver WH
      ↓                            ↓
  Gold WH ──────────────────── Gold WH
      │   (native dbt Mesh ref())   │
      └────────────┬───────────────┘
                   ↓
           dbt_poc_glb (Global)
              Gold WH (Sales)
              Gold WH (Finance)

Cross-project integration (dbt Mesh + Fabric Shortcuts)

• dbt_poc_glb/dependencies.yml declares the upstream projects dbt_poc_ita and dbt_poc_che for dbt Cloud Mesh governance.
• Upstream gold models are exposed with access: public and contract: { enforced: true }.
• Fabric cross-workspace constraint: Fabric Warehouse does not support direct cross-workspace SQL queries. Native dbt Mesh ref('dbt_poc_ita', '...') would generate SQL like gold_wh_ita.dbo_finance.dim_account which Fabric rejects (different workspace). The GLB models therefore use source() routing through Fabric Shortcuts in the GLB workspace (stg_lh_glb_sales, stg_lh_glb_finance) that point to the upstream ITA/CHE gold schemas. dependencies.yml is kept for project-level Mesh governance and dbt Cloud's project registry.
• This pattern ("Fabric-compatible dbt Mesh") is the recommended approach for multi-workspace Fabric + dbt Cloud setups until Fabric supports cross-workspace SQL natively.

Repository structure

dbt-mesh-poc/
├── dbt_poc_ita/           # Italy — dbt-fabric (Warehouse / T-SQL)
│   ├── models/
│   │   ├── silver/        # Staging layer (sales, finance)
│   │   └── gold/          # Gold layer (sales, finance) — access: public, contract: enforced
│   └── profiles.yml
├── dbt_poc_che/           # Switzerland — dbt-fabric (Warehouse / T-SQL)
│   ├── models/
│   │   ├── silver/
│   │   └── gold/          # access: public, contract: enforced
│   └── profiles.yml
├── dbt_poc_glb/           # Global — dbt-fabric (Warehouse / T-SQL)
│   ├── models/gold/       # Global gold layer (union of all countries via ref())
│   ├── dependencies.yml   # Native dbt Mesh: upstream projects
│   └── profiles.yml
├── scripts/               # Bronze seed scripts
│   ├── seed_bronze_che.sql
│   └── seed_bronze_ita.ipynb
├── .env.example
└── .gitignore

Running on dbt Cloud

Each project is configured as its own dbt Cloud project pointing at its subfolder in this monorepo, all on the main-cloud branch.

1. In each dbt Cloud project, set the Git branch to main-cloud and the project subdirectory to the matching folder (dbt_poc_ita, dbt_poc_che, dbt_poc_glb).
2. Configure each connection against the corresponding Fabric Warehouse with Service Principal authentication.
3. Run order: country projects first (Italy, Switzerland), then Global.

dbt build       # in dbt_poc_ita
dbt build       # in dbt_poc_che
dbt build       # in dbt_poc_glb   (resolves cross-project refs via dbt Mesh)

Fabric / T-SQL conventions

• No bare datetime — use datetime2(6).
• current_timestamp() (Spark) → CAST(SYSUTCDATETIME() AS datetime2(6)).
• trim() → ltrim(rtrim()); cast(... as boolean) → cast(... as bit); cast(... as timestamp) → cast(... as datetime2(6)).
• Enforced contracts must declare T-SQL types (varchar(n), bit, datetime2(6), decimal(18,2)), not Spark types.

Data domains

• Sales: dim_client, dim_branch, fct_sales_order
• Finance: dim_account, dim_cost_center, fct_journal_entry

Global models union both countries: *_global (e.g. dim_account_global, fct_sales_order_global).

Notes

• All credentials are injected via environment variables / dbt Cloud connection settings; no secrets are stored in version-controlled files.
• The documentation/, target/, dbt_packages/, and logs/ directories are excluded from version control.