314 lines
11 KiB
Markdown
314 lines
11 KiB
Markdown
# Super Graph
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## Instant GraphQL API for Rails. Zero code.
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Get an high-performance GraphQL API for your Rails app in seconds. Super Graph will auto learn your database structure and relationships. Built in support for Rails authentication and JWT tokens.
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## Back story and motivation
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I have a Rails app that gets a bit of traffic. Having planned to improve the UI using React or Vue I found that my current APIs didn't have the data I needed and I was too lazy to build new endpoints. My controllers were esentially wrappers around database queries and I didn't enjoy having to figure out new REST APIs with paths, names and methods to fetch all this new data or write the active record code needed.
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I always liked GraphQL and how simple it makes things for web devs. On the backend however GraphQL seemed overly complex as it still required me to write a lot of the same database query code. I wanted a GraphQL server that just worked the second you deployed it without having to write a line of code.
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And so after a lot of coffee and some avocado toasts we now have Super Graph, an instant GraphQL API that is high performance and quick to deploy. One service to rule all your database querying needs.
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## Features
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- Support for Rails database conventions
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- Belongs-To, One-To-Many and Many-To-Many table relationships
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- Devise, Warden encrypted and signed session cookies
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- Redis, Memcache and Cookie session stores
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- Generates highly optimized Postgres SQL queries
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- Customize through a simple config file
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- High performance GO codebase
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- Tiny docker image and low memory requirements
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### GraphQL (GQL)
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We currently support the `query` action which is used for fetching data. Support
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for `mutation` and `subscriptions` is currently work in progress. For example the below query fetches two products that belong to the current user where the price is greater than 10
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#### GQL Query
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```gql
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query {
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users {
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id
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email
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picture : avatar
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password
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full_name
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products(limit: 2, where: { price: { gt: 10 } }) {
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id
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name
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description
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price
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}
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}
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}
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```
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The above GQL query returns the JSON result below. It handles all
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kinds of complexity without you writing a line of code. For example there is a while greater than `gt` and a limit clause on a child field. And the `avatar` field is renamed to `picture`. The `password` field is blocked and not returned. Finally the relationship between the `users` table and the `products` table is auto discovered and used.
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#### JSON Result
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```json
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{
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"data": {
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"users": [
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{
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"id": 1,
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"email": "odilia@west.info",
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"picture": "https://robohash.org/simur.png?size=300x300",
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"full_name": "Edwin Orn",
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"products": [
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{
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"id": 16,
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"name": "Sierra Nevada Style Ale",
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"description": "Belgian Abbey, 92 IBU, 4.7%, 17.4°Blg",
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"price": 16.47
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},
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...
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]
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}
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]
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}
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}
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```
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## Try it out
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```console
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$ docker-compose run web rake db:create db:migrate db:seed
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$ docker-compose -f docker-compose.image.yml up
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$ open http://localhost:8080
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```
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The above command will download the latest docker image for Super Graph and use it to run an example that includes a Postgres DB and a simple Rails ecommerce store app. If you want to build and run Super Graph from code then use the following command instead `docker-compose up`
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#### How to try with an authenticated user
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In development mode you can use the `X-User-ID: 4` header to set a user id so you don't have to worries about cookies etc. This can be set using the *HTTP Headers* tab at the bottom of the web UI you'll see when you visit the above link. You can also directly run quries from the commandline like shown below.
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#### Querying the GQL endpoint
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```console
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curl 'http://localhost:8080/api/v1/graphql' \
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-H 'content-type: application/json' \
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-H 'X-User-ID: 5' \
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--data-binary '{"query":"{ products { name price users { email }}}"}'
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```
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## How to GraphQL
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GraphQL / GQL is a simple query syntax that is fast replacing REST APIs. GQL is great since it allows web developers to fetch the exact data that they need without depending on changes to backend code. Also if you squint hard enough it looks a little bit like JSON :)
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The below query will fetch a `users` name, email and avatar image renamed as picture. If you also need the users `id` then just add it to the query.
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```gql
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query {
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user {
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full_name
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email
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picture : avatar
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}
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}
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```
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Super Graph support complex quries where you can add filters, ordering, offsets and limits on the query.
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#### Logical Operators
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Name | Example | Explained |
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--- | --- | --- |
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and | price : { and : { gt: 10.5, lt: 20 } | price > 10.5 AND price < 20
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or | or : { price : { greater_than : 20 }, quantity: { gt : 0 } } | price >= 20 OR quantity > 0
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not | not: { or : { quantity : { eq: 0 }, price : { eq: 0 } } } | NOT (quantity = 0 OR price = 0)
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#### Other conditions
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Name | Example | Explained |
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--- | --- | --- |
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eq, equals | id : { eq: 100 } | id = 100
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neq, not_equals | id: { not_equals: 100 } | id != 100
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gt, greater_than | id: { gt: 100 } | id > 100
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lt, lesser_than | id: { gt: 100 } | id < 100
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gte, greater_or_equals | id: { gte: 100 } | id >= 100
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lte, lesser_or_equals | id: { lesser_or_equals: 100 } | id <= 100
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in | status: { in: [ "A", "B", "C" ] } | status IN ('A', 'B', 'C)
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nin, not_in | status: { in: [ "A", "B", "C" ] } | status IN ('A', 'B', 'C)
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like | name: { like "phil%" } | Names starting with 'phil'
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nlike, not_like | name: { nlike "v%m" } | Not names starting with 'v' and ending with 'm'
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ilike | name: { ilike "%wOn" } | Names ending with 'won' case-insensitive
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nilike, not_ilike | name: { nilike "%wOn" } | Not names ending with 'won' case-insensitive
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similar | name: { similar: "%(b\|d)%" } | [Similar Docs](https://www.postgresql.org/docs/9/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP)
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nsimilar, not_similar | name: { nsimilar: "%(b\|d)%" } | [Not Similar Docs](https://www.postgresql.org/docs/9/functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP)
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has_key | column: { has_key: 'b' } | Does JSON column contain this key
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has_key_any | column: { has_key_any: [ a, b ] } | Does JSON column contain any of these keys
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has_key_all | column: [ a, b ] | Does JSON column contain all of this keys
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contains | column: { contains: [1, 2, 4] } | Is this array/json column a subset of value
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contained_in | column: { contains: "{'a':1, 'b':2}" } | Is this array/json column a subset of these value
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is_null | column: { is_null: true } | Is column value null or not
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```javascript
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query {
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products(
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# returns only 30 items
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limit: 30,
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# starts from item 10, commented out for now
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# offset: 10,
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# orders the response items by highest price
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order_by: { price: desc },
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# no duplicate prices returned
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distinct: [ price ]
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# only items with an id >= 30 and < 30 are returned
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where: { id: { and: { greater_or_equals: 20, lt: 28 } } }) {
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id
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name
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price
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}
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}
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```
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## Web UI for web developers
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## Configuration
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Config files can either be in YAML or JSON their names are derived from the `GO_ENV` variable, for example `GO_ENV=prod` will cause the `prod.yaml` config file to be used. or `GO_ENV=dev` will use the `dev.yaml`. A path to the config files can be specified using the `-path <folder>` command line argument.
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```yaml
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host_port: 0.0.0.0:8080
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web_ui: true
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debug_level: 1
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# When to throw a 401 on auth failure
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# valid values: always, per_query, never
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auth_fail_block: never
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# Postgres related enviroment Variables
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# SG_DATABASE_HOST
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# SG_DATABASE_PORT
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# SG_DATABASE_USER
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# SG_DATABASE_PASSWORD
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# Auth related enviroment Variables
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# SG_AUTH_SECRET_KEY_BASE
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# SG_AUTH_PUBLIC_KEY_FILE
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# SG_AUTH_URL
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# SG_AUTH_PASSWORD
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# inflections:
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# person: people
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# sheep: sheep
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auth:
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type: header
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field_name: X-User-ID
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# auth:
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# type: rails
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# cookie: _app_session
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# store: cookie
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# secret_key_base: caf335bfcfdb04e50db5bb0a4d67ab9...
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# auth:
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# type: rails
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# cookie: _app_session
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# store: memcache
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# host: 127.0.0.1
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# auth:
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# type: rails
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# cookie: _app_session
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# store: redis
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# max_idle: 80,
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# max_active: 12000,
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# url: redis://127.0.0.1:6379
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# password: ""
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# auth:
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# type: jwt
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# cookie: _app_session
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# secret: abc335bfcfdb04e50db5bb0a4d67ab9
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# public_key_file: abc335bfcfdb04e50db5bb0a4d67ab9
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# public_key_type: ecdsa #rsa
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database:
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type: postgres
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host: db
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port: 5432
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dbname: app_development
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user: postgres
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password: ''
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#pool_size: 10
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#max_retries: 0
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#log_level: "debug"
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# Define variables here that you want to use in filters
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variables:
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account_id: "select account_id from users where id = $user_id"
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# Used to add access to tables
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filters:
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users: "{ id: { _eq: $user_id } }"
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posts: "{ account_id: { _eq: $account_id } }"
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# Fields and table names that you wish to block
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blacklist:
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- secret
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- password
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- encrypted
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- token
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```
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If deploying into enviroments like Kubernetes it's useful to be able to configure things like secrets and hosts though enviroment variables so we expose the following. This is escpecially useful for secrets since they are usually injected in via a secrets management framework ie. Kubernetes Secrets
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#### Postgres related enviroment Variables
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```console
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SG_DATABASE_HOST
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SG_DATABASE_PORT
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SG_DATABASE_USER
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SG_DATABASE_PASSWORD
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```
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#### Auth related enviroment Variables
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```console
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SG_AUTH_SECRET_KEY_BASE
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SG_AUTH_PUBLIC_KEY_FILE
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SG_AUTH_URL
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SG_AUTH_PASSWORD
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```
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## Deployment
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How do I deploy the Super Graph service with my existing rails app? You have several options here. Esentially you need to ensure your app's session cookie
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will be passed to this service.
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#### Deploy under a subdomain
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For this to work you have to ensure that the option `:domain => :all` is added to your rails app config `Application.config.session_store` this will cause your rails app to create session cookies that can be shared with sub-domains. More info here <http://excid3.com/blog/sharing-a-devise-user-session-across-subdomains-with-rails-3/>
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#### We have this NGINX loadbalancer
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I'm sure you know how to configure it so that the graphql endpoint path is routed to wherever you have this service installed within your architecture.
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#### On Kubernetes
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If your existing rails app runs on Kubernetes then ensure you have an ingress config deployed that points the path `/api/v1/graphql` to the service that you have deployed Super Graph under.
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#### We use JWT tokens like those from Auth0
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In that case deploy under a subdomain and configure this service to use JWT authentication. You will need the public key file or secret key. Ensure your web app passes the JWT token with every GQL request in the Authorize header as a `bearer` token.
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## Contact me
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[twitter.com/dosco](https://twitter.com/dosco)
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## License
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[MIT](http://opensource.org/licenses/MIT)
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Copyright (c) 2019-present Vikram Rangnekar
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