eolas-data

Python client for the eolas.fyi statistical data API — 1,500+ official New Zealand statistical & geospatial datasets, plus OECD data for international comparisons, served as tidy pandas DataFrames (or polars / geopandas if you prefer).

Coverage is New Zealand + OECD today. Australian sources are on the roadmap — not yet available; OECD data already includes Australia (and other OECD members) for cross-country comparisons.

pip install eolas-data

Quickstart

from eolas_data import Client

client = Client("your_api_key")   # or set EOLAS_API_KEY in env

# CPI index (monthly, RBNZ M1) — the usual Treasury/analyst choice
cpi = client.rbnz("rbnz_m1_prices", start="2020-01-01")

# OECD macro indicators (quarterly YoY % — not CPI index levels)
inflation = client.oecd("nz_cpi", start="2020-01-01")
gdp       = client.oecd("nz_gdp_growth")

# Discovery
all_datasets = client.list()
nz_only      = client.list("Stats NZ")
client.search("cpi")   # expands aliases; surfaces rbnz_m1_prices before nz_cpi
meta         = client.info("rbnz_m1_prices")

Get an API key at https://eolas.fyi/signup. Free plan is 10 requests/month; Pro ($49/month) is unlimited.

Quick setup (workstation)

Two one-off commands make every future session frictionless:

1. Save your API key to the OS keyring (macOS Keychain / Windows Credential Manager / Linux Secret Service) so Client() finds it automatically — no env var, no pasting:

pip install 'eolas-data[secure]'   # adds the keyring package
eolas auth save-key                # interactive prompt

from eolas_data import Client
client = Client()   # key read from OS keyring automatically

2. Set a library directory so downloaded bulk files land somewhere permanent instead of the transient ~/.cache/eolas/ OS cache:

eolas library set ~/eolas-library  # writes to ~/.eolas/config.json

Or set the env var instead (useful for CI / Docker):

export EOLAS_LIBRARY=~/eolas-library

After setting the library, client.get_local("nz_parcels") will use ~/eolas-library/ automatically.

The keyring slot and config file are shared with the R eolas client — a key saved from Python is immediately readable from R and vice versa (see the R client README).

Command-line interface

pip install eolas-data includes the eolas CLI for browsing, fetching, and scheduling — useful for shell scripts, cron jobs, and AI-agent workflows. Rich tables by default; pass --json for newline-delimited JSON in scripts.

# one-time setup (OS keyring — recommended)
pip install 'eolas-data[secure]'
eolas auth save-key

# or config file (no extra install)
eolas auth set-key
eolas health

# discover
eolas datasets list --source "Stats NZ"
eolas datasets list --search cpi          # table + CPI guidance note
eolas datasets list --search cpi --json | jq '.[].name'
eolas datasets info rbnz_m1_prices
eolas datasets preview rbnz_m1_prices --limit 5

# fetch (verb matches the Python lib's client.get())
eolas get rbnz_m1_prices --format csv > cpi.csv
eolas get nz_cpi --start 2020-01-01 --format json | jq '.[].value'   # OECD YoY %
eolas get nz_meshblock_2023 --format parquet --out sa2.parquet

Scheduling

Set up recurring fetches without touching crontab/Task Scheduler syntax. Works on Linux, macOS (cron), and Windows (Task Scheduler).

eolas schedule add nz_cpi --daily   --out ~/data/cpi.csv
eolas schedule add nz_gdp_growth --weekly  --out ~/data/gdp.csv
eolas schedule add rbnz_b1_exchange_rates_monthly --cron "0 */6 * * *" --out ~/data/fx.csv   # POSIX only

eolas schedule list
eolas schedule remove nz_cpi

Daily is the default. Pre-flight check refuses to install a schedule unless your API key is configured (otherwise the job would fail silently forever).

Integrations (Enterprise plan)

Generate ready-to-run connector configs for popular data-pipeline tools — eolas becomes a one-command source for Meltano, Fivetran, or Azure Data Factory.

eolas integrate meltano             --datasets nz_cpi,nz_gdp_growth --output ./my-pipeline/
eolas integrate fivetran            --datasets nz_cpi
eolas integrate azure-data-factory  --datasets nz_cpi,nz_gdp_growth

The generated directory has everything needed to plug into your destination warehouse: meltano.yml, fivetran.yml, or ADF JSON resources, plus a README.md walking through the rest of the setup. Non-Enterprise users see a clear upgrade pointer; the gating lives server-side so the capability is bypass-proof.

Exit codes

Distinct exit codes per error class, for shell scripts and agents:

Performance (Arrow)

client.get() transparently negotiates Apache Arrow over the wire — same DataFrame back, typically 5–10× faster end-to-end on large pulls, with an automatic JSON fallback. No setup: pyarrow ships with eolas-data, so this is on by default; format= ("json"/"csv") is only for the rare case you want the raw text payload.

For a columnar file (CLI), use --format parquet --out FILE; via the REST API directly, ?format=parquet. Full benchmark: docs.eolas.fyi → Python reference → Performance.

Bulk downloads — use get_local() for whole datasets

client.get() hits the live /data endpoint (good for slices and small pulls). For whole datasets — especially large or geospatial layers — use get_local(). It syncs a CDN-cached Parquet/GeoParquet file to your library directory and reads from disk on subsequent calls.

# Whole-dataset path: nz_parcels from CDN-cached GeoParquet (seconds, not a 15-min Iceberg scan)
gdf = client.get_local("nz_parcels")   # geopandas.GeoDataFrame when [geo] is installed
df  = client.get_local("nz_cpi")       # tidy DataFrame from cached Parquet

# Live path: date slices, row limits, licence-restricted sources (e.g. OECD)
df  = client.get("nz_cpi", start="2020-01-01")
df  = client.get("nz_cpi", limit=100)

Use get_local() when you need to control cache_dir, format, or freshness:

# Explicit cache+sync with extra options
gdf = client.get_local("nz_parcels")
gdf = client.get_local("nz_parcels", cache_dir="/data/eolas", freshness="monthly")
df  = client.get_local("nz_cpi", format="csv_gz")

For advanced control over the sync lifecycle (sidecar tracking, atomic replace), use sync_bulk() directly. For one-shot bytes-or-path downloads, use download_bulk():

r    = client.sync_bulk("nz_cpi", path="nz_cpi.parquet")
# r.status ∈ {"downloaded", "unchanged", "updated"}; r.bytes_downloaded == 0 when unchanged.
path = client.download_bulk("treasury_fiscal_spending", path="t.parquet")

Progress bars: get_local() shows two phases in interactive sessions — a download byte bar while fetching from CDN, then a read spinner while Parquet/GeoParquet is loaded (often the slow part on multi-million-row geo datasets). Control with progress=True (both), False (neither), "download", or "read". Set EOLAS_NO_PROGRESS=1 to suppress both in batch scripts. Cached files skip the download bar and print an informative message instead.

CLI mirror: eolas download <name> for one-shot, eolas sync <name> [--watch hourly] for an incremental check. Full docs: docs.eolas.fyi/bulk-downloads/.

Sync — always-fresh local copy

client.sync(name, path) keeps a local file current, automatically choosing how based on the dataset's CDC serving tier — you make the same call either way:

• snapshot-tier datasets → full-snapshot download, re-fetched only when the server snapshot changes (sync_bulk()).
• changelog-tier datasets (e.g. the LINZ SCD2 layers) → incremental: the first call downloads a baseline, then later calls fetch only what changed from the /changes feed and pk-merge it into your file (sync_changes()).

# Same call regardless of tier:
r = client.sync("nz_building_outlines", path="buildings.parquet")
r.status        # "downloaded" (baseline) | "updated" | "unchanged"
r.sync_mode     # "changelog" for changelog-tier datasets
r.ops_applied   # number of change rows applied this run
r.current_seq   # feed watermark after this sync

# First call baselines; subsequent calls apply only new changes:
r = client.sync("nz_building_outlines", path="buildings.parquet")
r.ops_applied   # e.g. 1240

A sidecar at str(path) + ".eolas-meta.json" records the snapshot id / feed watermark so the next call fetches only new data. For SCD2 datasets the merge keeps only the current rows (is_current = true), so buildings.parquet is always a clean current-state snapshot — the SCD2 history is handled for you. A 410 (watermark expired) self-heals by re-baselining.

The changelog sidecar (schema_version 2) is byte-compatible with the R eolas client: a file synced from Python can be resumed from R and vice versa.

Geospatial

Datasets with a geometry_wkt column auto-convert to geopandas.GeoDataFrame if geopandas is installed:

pip install eolas-data[geo]

gdf = client.get("nz_addresses")                  # GeoDataFrame
df  = client.get("nz_addresses", as_geo=False)    # plain DataFrame, WKT preserved

Working with large geo datasets

The 5.4M-row linz.nz_parcels table allocates ~10 GB when materialised as a GeoDataFrame. Pass as_arrow=True to skip all shapely allocation and get a zero-copy pyarrow.Table instead — geometry stays as Arrow buffers until you need it:

# Zero-copy Arrow table — no shapely allocation
tbl = client.linz("nz_parcels", as_arrow=True)

# Filter before materialising — dramatically cheaper than loading the full GeoDataFrame
import duckdb
result = duckdb.sql("""
    SELECT parcel_id, geometry_wkt
    FROM tbl
    WHERE ST_Within(ST_GeomFromText(geometry_wkt),
                    ST_GeomFromText('POLYGON((174.7 -41.3, 174.8 -41.3, 174.8 -41.4, 174.7 -41.4, 174.7 -41.3))'))
""").df()

as_arrow=True works on all datasets (geo or non-geo), all routing modes (live, cached, auto), and all source helpers. It cannot be combined with as_geo=True.

Polars

pip install eolas-data[polars]

df = client.get("nz_cpi", engine="polars")

Plotting

Dataset is a pandas.DataFrame subclass — use matplotlib / seaborn / plotly directly. No bundled plot helper, because there's no universal "right" plot for a tidy dataset (single-series time series vs. wide multi-measure vs. WKT geometry all need different code).

import matplotlib.pyplot as plt

df = client.statsnz("nz_cpi")
df.plot(x="date", y="value")
plt.show()

Type stubs

Dataset names are exposed as a Literal so IDEs autocomplete the catalog:

from eolas_data import Client

client = Client()
client.get("nz_")    # autocomplete shows nz_cpi, nz_gdp_growth, ...

The list is regenerated from the live API at release time. Passing a name not in the snapshot still works at runtime — the type hint just won't autocomplete it. Catalog snapshot date is exposed as eolas_data._dataset_names.CATALOG_SNAPSHOT_DATE.

Testing

# unit tests (mocked HTTP — no API key needed)
pytest -q -m "not integration"

# live smoke (requires EOLAS_API_KEY)
EOLAS_API_KEY=vs_... pytest -q -m integration tests/test_smoke_live.py

CI runs the unit suite on Python 3.10, 3.12, and 3.13 on every push/PR, with coverage uploaded to Codecov. A weekly workflow optionally runs live smoke tests when EOLAS_API_KEY is configured as a repository secret.

Releasing

See docs/clients.md in the eolas data repo for the tagged-release flow and PyPI token rotation.

Before each release: python -m eolas_data._regen_names to refresh the dataset name stubs from the live API, commit the change, then tag and push.

License

MIT — applies to this client software only. Dataset use is subject to each source's licence and your eolas API plan.