Test 20 databases on every commit @ PyCon 2024

It’s not hyperbole

Phillip Cloud

2024-05-19

Who

Me

• Phillip Cloud
• Ibis project
• Voltron Data
• Data tools for 10+ years

Where

• @cpcloud
• Phillip in the Cloud
• @cpcloudy

What

Maybe this is you

Or this

Or maybe even this

Not earth shattering

Overview

• What we learned about maintenance
• Day to day of 20+ databases
• Unique challenges

Tools

• Docker
• Packaging
• CI
• pytest plugins

Overview of Ibis

Ibis is a Python library for:

• Exploratory data analysis (EDA)
• Analytics
• Data engineering
• ML preprocessing
• Building your own DataFrame lib

Dev to prod with the same API

One API, 20+ backends

• DuckDB
• Polars
• DataFusion
• PySpark
• 16+ other things

con = ibis.connect("duckdb://")

t = con.read_parquet("penguins.parquet")
t.head(3)

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

t.group_by("species", "island").agg(count=t.count()).order_by("count")

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ int64 │
├───────────┼───────────┼───────┤
│ Adelie    │ Biscoe    │    44 │
│ Adelie    │ Torgersen │    52 │
│ Adelie    │ Dream     │    56 │
│ Chinstrap │ Dream     │    68 │
│ Gentoo    │ Biscoe    │   124 │
└───────────┴───────────┴───────┘

con = ibis.connect("polars://")

t = con.read_parquet("penguins.parquet")
t.head(3)

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

t.group_by("species", "island").agg(count=t.count()).order_by("count")

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ int64 │
├───────────┼───────────┼───────┤
│ Adelie    │ Biscoe    │    44 │
│ Adelie    │ Torgersen │    52 │
│ Adelie    │ Dream     │    56 │
│ Chinstrap │ Dream     │    68 │
│ Gentoo    │ Biscoe    │   124 │
└───────────┴───────────┴───────┘

con = ibis.connect("datafusion://")

t = con.read_parquet("penguins.parquet")
t.head(3)

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

t.group_by("species", "island").agg(count=t.count()).order_by("count")

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ int64 │
├───────────┼───────────┼───────┤
│ Adelie    │ Biscoe    │    44 │
│ Adelie    │ Torgersen │    52 │
│ Adelie    │ Dream     │    56 │
│ Chinstrap │ Dream     │    68 │
│ Gentoo    │ Biscoe    │   124 │
└───────────┴───────────┴───────┘

con = ibis.connect("pyspark://")

t = con.read_parquet("penguins.parquet")
t.head(3)

┏━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━┓
┃ species ┃ island    ┃ bill_length_mm ┃ bill_depth_mm ┃ flipper_length_mm ┃ body_mass_g ┃ sex    ┃ year  ┃
┡━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━┩
│ string  │ string    │ float64        │ float64       │ int64             │ int64       │ string │ int64 │
├─────────┼───────────┼────────────────┼───────────────┼───────────────────┼─────────────┼────────┼───────┤
│ Adelie  │ Torgersen │           39.1 │          18.7 │               181 │        3750 │ male   │  2007 │
│ Adelie  │ Torgersen │           39.5 │          17.4 │               186 │        3800 │ female │  2007 │
│ Adelie  │ Torgersen │           40.3 │          18.0 │               195 │        3250 │ female │  2007 │
└─────────┴───────────┴────────────────┴───────────────┴───────────────────┴─────────────┴────────┴───────┘

t.group_by("species", "island").agg(count=t.count()).order_by("count")

┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━┓
┃ species   ┃ island    ┃ count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━┩
│ string    │ string    │ int64 │
├───────────┼───────────┼───────┤
│ Adelie    │ Biscoe    │    44 │
│ Adelie    │ Torgersen │    52 │
│ Adelie    │ Dream     │    56 │
│ Chinstrap │ Dream     │    68 │
│ Gentoo    │ Biscoe    │   124 │
└───────────┴───────────┴───────┘

How it works

What’s in an Ibis?

By the numbers

Backends

• 17 SQL
• 3 non-SQL
• 2 cloud

Engines + APIs

• 9 distributed SQL
• 3 dataframe
• oldest: ~45 years 👀
• youngest: ~2 years

Other facts

• Latency is variable
• Deployment models vary

… Feature development❓

Bit of a pickle

How

High level

Goal: fast iteration

• fast env setup (dependency management)
• fast(ish) tests (test-running library)
• high job concurrency (ci/provider)
• easy to run: dev speed (just)

CI must complete “quickly”

Tools: overview

• 📦 poetry
• 🖥️ GitHub Actions
• 🦁 docker
• 🐕 docker
• 🐱 no special tx (duckdb, polars)
• 🏃 task runner (e.g.: just up postgres)

Tools: poetry

Opinions follow

Opinions herein…

• Env setup needs to be fast: avoid constraint solving
• Poetry is one way; there are others
• Get yourself a lockfile
• Downsides?

… Are you doing that now❓

This plot

 

We’ve added 3 or 4 new backends since the switch

Tools: docker

• Sure, docker
• But, do you to use it locally?
• Use health checks; “dumb” ones are fine
• Make it easy for devs to use

Tools: GitHub Actions

I don’t work for GitHub

…even though it might seem like it

• Pay for the the Teams plan to get more concurrency
• Automate dependency updates

GHA concurrency limits

Ibis CI cost

pytest

Ibis problems

• Tests run across ALL backends
• Backends don’t implement the same stuff
• Need to know when backend passes
• Answer questions like: “will it ever blend?”

Markers + hooks

@pytest.mark.never("duckdb")  # never gonna happen
@pytest.mark.notyet("impala")  # might happen
@pytest.mark.notimpl("snowflake")  # ibis devs: do some work
def test_soundex():
    ...

def pytest_ignore_collect(...):
    # pytest -m duckdb: don't collect things that aren't marked duckdb
    ...

pytest plugins you may like

pytest-

• xdist: make this work if you can
• randomly: break your bogus stateful assumptions
• repeat: when randomly exposes your assumptions
• clarity: readable test failure messages
• snapshot: better than the giant f-string you just wrote

hypothesis 👈 that too, we don’t use it enough

Why pytest-randomly?

Summary

• Use docker for dev and prod
• Lock your dependencies (dev only!)
• Auto update stuff
• pytest probably has a thing for that
• Spend time on dev ex
• Track CI run durations, look at them too

Questions?