Load Dagger data to DuckDB
Build a Dagger to DuckDB pipeline with your coding agent. One prompt scaffolds it with the dltHub AI harness, plus the Dagger API base URL, auth, endpoints, and incremental loading.
Dagger is a development engine that exposes its build/run/test capabilities as a local GraphQL HTTP API. Everything needed to build a working Dagger → DuckDB pipeline is on this page: the API's base URL, authentication, endpoints, pagination and incremental field — plus a prompt that hands the whole job to your coding agent.
Build your Dagger to DuckDB pipeline
Paste this prompt into Claude, Codex, or Cursor. The agent does the rest.
PromptRunuvx dlthub-init@latestto build a pipeline from Dagger to DuckDB and run it on dltHub
That scaffolds a dltHub workspace and installs the dltHub AI harness — the project rules, the secrets-management skill, and the dlt MCP server your agent needs to work safely. From there it reads the Dagger API, proposes the endpoints to load, then writes, runs and validates the pipeline while you review rather than type. Credentials are inspected through MCP tools, so your agent never reads secrets.toml itself. How the LLM-native workflow works →
Prefer to write it yourself? Every fact the agent uses is below.
Dagger API at a glance
| Base URL | http://127.0.0.1:$DAGGER_SESSION_PORT/query |
| Example endpoint | POST query |
| Records found at | data.container |
| Authentication | HTTP Basic authentication using the session token as the username and an empty password — sent in the Authorization header, prefixed Basic |
| Pagination | Not paginated |
| API reference | https://docs.dagger.io/getting-started/api/http/ |
These values come from the Dagger API reference — the authoritative source if anything here looks out of date.
How do I authenticate with the Dagger API?
The Dagger API uses HTTP Basic authentication. The username is the value of the DAGGER_SESSION_TOKEN environment variable and the password must be empty.
1. Get your credentials
To obtain a Dagger Cloud token, follow these steps: 1. Log in to your Dagger Cloud account at https://dagger.cloud. 2. Click the cogwheel icon in the top navigation bar to access the settings page. 3. Navigate to the Tokens sub-menu. 4. Click the eye icon to reveal and copy your token. Alternatively, you can use the URL pattern: https://dagger.cloud/{Your_Org_Name}/settings?tab=Tokens.
2. Add them to .dlt/secrets.toml
[sources.dagger_source] DAGGER_CLOUD_TOKEN = "your_token_here"
dlt reads this file automatically at runtime. With the harness, the setup-secrets skill prompts you for the values and never handles the raw credential in chat. For production, see setting up credentials with dlt.
What Dagger data can I load into DuckDB?
These are the Dagger endpoints dlt can load into DuckDB:
| Resource | Endpoint | Method | Data selector | Description |
|---|---|---|---|---|
| container | query | POST | data.container | Operations to create, load, or execute commands in containers |
| http | query | POST | data.http | Fetches content from a remote HTTP URL |
| secret | query | POST | data.secret | Accesses secret objects within the Dagger engine |
| service | query | POST | data.service | Manages service-related lifecycles and endpoints |
| cache_volume | query | POST | data.cacheVolume | Manages persistent cache volumes in the engine |
How do I load only new Dagger records?
The Dagger API reference does not document a timestamp or sequence field for these endpoints, so there is nothing to advertise here as verified. Pick a field from the endpoints table above that increases with every write, then set it as the cursor_path.
{"name": "container", "endpoint": { "path": "query", # Replace with a field that increases on every write. "incremental": {"cursor_path": "REPLACE_ME", "initial_value": "2024-01-01T00:00:00Z"}, }}
On the first run dlt loads everything from initial_value; on every run after that it requests only what changed and appends with write_disposition="merge" if you set a primary key. See incremental loading.
What does the generated Dagger pipeline look like?
A standard dlt REST API pipeline — the same code you would write by hand, loading /query and / (for the GraphQL engine session) from the Dagger API into DuckDB:
import dlt from dlt.sources.rest_api import RESTAPIConfig, rest_api_resources @dlt.source def dagger_source(session_token=dlt.secrets.value): config: RESTAPIConfig = { "client": { "base_url": "http://127.0.0.1:$DAGGER_SESSION_PORT/query", "auth": {"type": "http_basic", "username": "REPLACE_ME", "password": session_token}, }, "resources": [ {"name": "container", "endpoint": {"path": "query", "data_selector": "data.container"}}, {"name": "http", "endpoint": {"path": "query", "data_selector": "data.http"}} ], } yield from rest_api_resources(config) def load_dagger_to_duckdb() -> None: pipeline = dlt.pipeline( pipeline_name="dagger_pipeline", destination="duckdb", dataset_name="dagger_data", ) load_info = pipeline.run(dagger_source()) print(load_info) if __name__ == "__main__": load_dagger_to_duckdb()
Run it with python dagger_pipeline.py. The agent iterates on this until it loads cleanly — you review and approve, rather than write it from scratch.
How do I query Dagger data in DuckDB?
dlt creates one table per resource. Query the loaded data with Python or SQL — or ask your agent to, through the MCP server's execute_sql_query tool.
Python (pandas DataFrame):
import dlt data = dlt.pipeline("dagger_pipeline").dataset() df = data.query.df() print(df.head())
SQL:
SELECT * FROM dagger_data.query LIMIT 10;
See querying your data with dataset and exploring it in marimo notebooks.
How do I deploy the Dagger to DuckDB pipeline in production?
The pipeline runs locally, which is ideal for prototyping and one-off analysis. When you need it on a schedule, monitored on every load, and shared with your team, deploy the same dlt code on the dltHub platform — no infrastructure to maintain. The prompt above already ends with "run it on dltHub", so your agent can take it there directly.
- Deploy & schedule — run the pipeline as a managed job with automatic retries.
- Monitor — observable job queues, alerting, and load metrics for every run.
- Transform — promote raw Dagger loads into governed, documented models.
- Visualize & share — explore data in notebooks and publish live dashboards instead of static screenshots.
What other destinations can I load Dagger data to?
dlt loads into any of these — only the destination argument changes:
| Destination | Example value |
|---|---|
| PostgreSQL | "postgres" |
| BigQuery | "bigquery" |
| Snowflake | "snowflake" |
| Redshift | "redshift" |
| Databricks | "databricks" |
| Filesystem (S3, GCS, Azure) | "filesystem" |
Set dlt.pipeline(destination="snowflake") and add credentials in .dlt/secrets.toml. On the dltHub platform the same pipeline runs against a managed Iceberg lakehouse. See the full destinations list.
Next steps
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