Architecture Overview

The Cal-ITP data infrastructure facilitates several types of data workflows:

  • Ingestion

  • Modeling/transformation

  • Analysis

In addition, we have Infrastructure tools that monitor the health of the system itself or deploy or run other services and do not directly interact with data or support end user data access.

At a high level, the following diagram outlines (in very broad terms) the main tools that we use in our data stack (excluding Infrastructure tools).

flowchart LR subgraph ingestion/[ ] ingestion_label[Ingestion/Orchestration] airflow[Airflow] python[Python scripts] gcs[Google Cloud Storage] airflow --schedules/executes--> python python --save data to-->gcs end subgraph modeling[ ] modeling_label[Modeling/Transformation] bq[BigQuery] dbt[dbt] gcs--data read into-->bq bq <--SQL data transformations--> dbt python -- execute--> dbt end subgraph analysis[ ] analysis_label[Analysis] metabase[Metabase] jupyter[JupyterHub] open_data[California Open Data] python -- execute publish to--> open_data end bq -- data accessible in--> analysis classDef default fill:white, color:black, stroke:black, stroke-width:1px classDef group_labelstyle fill:#cde6ef, color:black, stroke-width:0px class ingestion_label,modeling_label,analysis_label group_labelstyle

This documentation outlines two ways to think of this system and its components from a technical/maintenance perspective:

  • Services that are deployed and maintained (ex. Metabase, JupyterHub, etc.)

  • Data pipelines to ingest specific types of data (ex. GTFS Schedule, Payments, etc.)


Across both data and services, we often have a “production” (live, end-user-facing) environment and some type of testing, staging, or development environment.


  • Managed Airflow (i.e. Google Cloud Composer)

  • Production gtfs-rt-archiver-v3

  • cal-itp-data-infra database (i.e. project) in BigQuery

  • Google Cloud Storage buckets without a prefix

    • e.g. gs://calitp-gtfs-schedule-parsed-hourly


  • Locally-run Airflow (via docker-compose)

  • Test gtfs-rt-archiver-v3

  • cal-itp-data-infra-staging database (i.e. project) in BigQuery

  • GCS buckets with the test- prefix

    • e.g. gs://test-calitp-gtfs-rt-raw-v2

    • Some buckets prefixed with dev- also exist; primarily for testing the RT archiver locally