From af7f7f5de7b6c17d7fac799dc4102afd05e8c5d1 Mon Sep 17 00:00:00 2001 From: Sean Mackesey Date: Fri, 20 Dec 2024 15:48:50 -0500 Subject: [PATCH] [components] [docs] Initial components guide --- .../docs-beta/docs/guides/build/components.md | 202 ++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 docs/docs-beta/docs/guides/build/components.md diff --git a/docs/docs-beta/docs/guides/build/components.md b/docs/docs-beta/docs/guides/build/components.md new file mode 100644 index 0000000000000..dbcc57d260ac7 --- /dev/null +++ b/docs/docs-beta/docs/guides/build/components.md @@ -0,0 +1,202 @@ +--- +title: "Components" +sidebar_position: 200 +--- + +Welcome to Dagster Components. + +Dagster Components is a new way to structure your Dagster projects. It aims to provide: + +- An opinionated project layout that supports ongoing scaffolding from “Hello world” to the most advanced projects +- A class-based interface for dynamically constructing definitions +- A toolkit to build YAML DSL frontends for components so that components can be constructed in a low-code fashion. +- A format for components to provide their own scaffolding, in order to organize and reference integration-specific artifacts files. + +## Project Setup + +First let's install the `dg` command line tool. This lives in the published Python package `dagster-dg`. `dg` is designed to be globally installed and has no dependency on `dagster` itself. We will use the tool feature of Python package manager `uv` to install a globally available `dg`. `dg` will also be use `uv` internally to manage the python enviroment associated with your project. + +```bash +brew install uv && uv tool install -e -e $DAGSTER_GIT_REPO_DIR/python_modules/libraries/dagster-dg/ +``` + +Let's have a look at what's available: + +```bash +dg --help + +Usage: dg [OPTIONS] COMMAND [ARGS]... + + CLI tools for working with Dagster components. + +Commands: + code-location Commands for operating code location directories. + component Commands for operating on components. + component-type Commands for operating on components types. + deployment Commands for operating on deployment directories. + +Options: + --builtin-component-lib TEXT Specify a builitin component library to use. + --verbose Enable verbose output for debugging. + --disable-cache Disable caching of component registry data. + --clear-cache Clear the cache before running the command. + --rebuild-component-registry Recompute and cache the set of available component types for the current environment. + Note that this also happens automatically whenever the cache is detected to be stale. + --cache-dir PATH Specify a directory to use for the cache. + -v, --version Show the version and exit. + -h, --help Show this message and exit. +``` + +We're going to generate a new code location. + +```bash +dg code-location generate jaffle_platform +``` + +Let's have a look at what it generated: + +```bash +cd jaffle_platform && tree +``` + +You can see that we have a basic project structure with a few non-standard files/directories: + +- `jaffle_platform/components`: this is where we will define our components +- `jaffle_platform/lib`: this is where we can put custom component types +- `definitions.py`: this comes preloaded with some basic code that will scrape up and merge all the Dagster definitions from our components. + +## Hello Platform + +We are going to set up a data platform using sling to ingest data, dbt to process the data, and python to do AI. + +### Ingest + +First we set up sling. If we query the available component-types in our code location, we don't see anything sling-related: + +```bash +dg component-type list + +dagster_components.pipes_subprocess_script_collection + Assets that wrap Python scripts executed with Dagster's PipesSubprocessClient. +``` + +This is because the basic `dagster-components` package is lightweight and doesn't include copmonents for specific tools. We can get access to a `sling` component by installing the `sling` extra: + +```bash +uv add 'dagster-components[sling]' dagster-embedded-elt +``` + +Now let's see what's available: + +```bash +dg component-type list + +dagster_components.pipes_subprocess_script_collection + Assets that wrap Python scripts executed with Dagster's PipesSubprocessClient. +dagster_components.sling_replication` +``` + +Great-- we now have the `dagster_components.sling_replication` component type available. Let's create a new instance of this component: + +```bash +dg component generate dagster_components.sling_replication ingest_files + +Creating a Dagster component instance folder at /Users/smackesey/stm/code/elementl/tmp/jaffle_platform/jaffle_platform/components/ingest_files. +``` + +This adds a component instance to the project at `jaffle_platform/components/ingest_files`: + +```bash +tree jaffle_platform + +jaffle_platform/ +├── __init__.py +├── __pycache__ +│   └── __init__.cpython-312.pyc +├── components +│   └── ingest_files +│   ├── component.yaml +│   └── replication.yaml +├── definitions.py +└── lib + ├── __init__.py + └── __pycache__ + └── __init__.cpython-312.pyc + +6 directories, 7 files +``` + +Notice that our component has two files: `component.yaml` and `replication.yaml`. The `component.yaml` file is common to all Dagster components, and specifies the component type and any associated parameters. Right now the parameters are empty: + +```yaml +### jaffle_platform/components/ingest_files/component.yaml +component_type: dagster_components.sling_replication + +params: {} +``` + +The `replication.yaml` file is a sling-specific file. + +We want to replicate data on the public internet into duckdb: + +```bash +uv run sling conns set DUCKDB type=duckdb instance=/tmp/jaffle_platform.duckdb + +4:55PM INF connection `DUCKDB` has been set in /Users/smackesey/.sling/env.yaml. Please test with `sling conns test DUCKDB` +``` + +```bash +uv run sling conns test DUCKDB + +4:55PM INF success! +``` + +Now let's download a file locally (sling doesn’t support reading from the public internet): + +```bash +curl -O https://raw.githubusercontent.com/dbt-labs/jaffle-shop-classic/refs/heads/main/seeds/raw_customers.csv && +curl -O https://raw.githubusercontent.com/dbt-labs/jaffle-shop-classic/refs/heads/main/seeds/raw_orders.csv && +curl -O https://raw.githubusercontent.com/dbt-labs/jaffle-shop-classic/refs/heads/main/seeds/raw_payments.csv +``` + +And copy-paste the below code into `replication.yaml`: + +```yaml +source: LOCAL +target: DUCKDB + +defaults: + mode: full-refresh + object: "{stream_table}" + +streams: + file://raw_customers.csv: + object: "main.raw_customers" + file://raw_orders.csv: + object: "main.raw_orders" + file://raw_payments.csv: + object: "main.raw_payments" +``` + +Let's load up our code location in the Dagster UI to see what we've got: + +```bash +uv run dagster dev # will be dg dev in the future +``` + +Click "Materialize All", and we should now have tables in the DuckDB instance. Let's verify on the command line: + +``` +brew install duckdb +duckdb /tmp/jaffle_platform.duckdb -c "SELECT * FROM raw_customers LIMIT 5;" +┌───────┬────────────┬───────────┬──────────────────┐ +│ id │ first_name │ last_name │ _sling_loaded_at │ +│ int32 │ varchar │ varchar │ int64 │ +├───────┼────────────┼───────────┼──────────────────┤ +│ 1 │ Michael │ P. │ 1734732030 │ +│ 2 │ Shawn │ M. │ 1734732030 │ +│ 3 │ Kathleen │ P. │ 1734732030 │ +│ 4 │ Jimmy │ C. │ 1734732030 │ +│ 5 │ Katherine │ R. │ 1734732030 │ +└───────┴────────────┴───────────┴──────────────────┘ +```