ThinIce - Standalone Iceberg REST Catalog Proxy

Apache Iceberg is a big data system which is effectively a set of columnar data files and a metadata catalog of what data's in those files. You can get one off the shelf from many vendors and providers, but for local dev that can be annoying.

So this is a simple local mock/proxy for multitenanted Iceberg. This means the user gets a token, and sees an Iceberg limited only to the tenant they're using (eg, MyCompany). However under the covers, we can use flat file storage or service role IAM to S3 etc without having to link the user identity to the upstream provider directly.

This is a service layer using bearer tokens, it is not a browser based webapp.

API (Complete Core Iceberg REST Catalog)

Configuration

Method	Path	Status
GET	/v1/config	✓ Implemented

Namespaces

Method	Path	Status
GET	/v1/namespaces	✓ Implemented
POST	/v1/namespaces	✓ Implemented
GET	/v1/namespaces/{ns}	✓ Implemented
HEAD	/v1/namespaces/{ns}	✓ Implemented
POST	/v1/namespaces/{ns}/properties	✓ Implemented
DELETE	/v1/namespaces/{ns}	✓ Implemented
POST	/v1/namespaces/{ns}/register	✓ Implemented

Tables

Method	Path	Status
GET	/v1/namespaces/{ns}/tables	✓ Implemented
POST	/v1/namespaces/{ns}/tables	✓ Implemented
GET	/v1/namespaces/{ns}/tables/{table}	✓ Implemented
POST	/v1/namespaces/{ns}/tables/{table}	✓ Implemented (commit updates)
HEAD	/v1/namespaces/{ns}/tables/{table}	✓ Implemented
DELETE	/v1/namespaces/{ns}/tables/{table}	✓ Implemented
POST	/v1/tables/rename	✓ Implemented

Data Storage

Method	Path	Status
GET	/v1/data/{path}	✓ Implemented (streaming blob read)
PUT	/v1/data/{path}	✓ Implemented (streaming blob write)

Note: Advanced features like views, transactions, scan planning, metrics, and vended credentials are not implemented. This implementation provides a complete core REST catalog suitable for local development and testing.

Usage

Running the app

dotnet run --project src/Meeze.ThinIce.App

The app starts on http://localhost:5000 by default.

Running tests

dotnet test ThinIce.sln

Publishing (AOT native binary)

dotnet publish src/Meeze.ThinIce.App -c Release

API examples

The development config (appsettings.Development.json) ships with two tokens:

• freeze-ray-token-001 → tenant SnowyConesIceCream, user mrfreeze@example.com
• ice-age-token-002 → tenant WayneEnterprises, user batman@example.org

Get catalog config:

curl http://localhost:5000/v1/config

Create a namespace:

curl -X POST http://localhost:5000/v1/namespaces \
  -H "Authorization: Bearer <access_token>" \
  -H "Content-Type: application/json" \
  -d '{"namespace": ["analytics"], "properties": {"owner": "data-team"}}'

List namespaces:

curl http://localhost:5000/v1/namespaces \
  -H "Authorization: Bearer <access_token>"

Create a table:

curl -X POST http://localhost:5000/v1/namespaces/analytics/tables \
  -H "Authorization: Bearer <access_token>" \
  -H "Content-Type: application/json" \
  -d '{"name": "events", "schema": {"type": "struct", "fields": [{"id": 1, "name": "ts", "type": "timestamp", "required": true}]}}'

Write data (blob):

curl -X PUT http://localhost:5000/v1/data/warehouse/events/data.parquet \
  -H "Authorization: Bearer <access_token>" \
  -H "Content-Type: application/octet-stream" \
  --data-binary @data.parquet

Read data (blob):

curl http://localhost:5000/v1/data/warehouse/events/data.parquet \
  -H "Authorization: Bearer <access_token>" \
  -o data.parquet