Custom Open Policy Agent with prototypical support for OpenFGA

This experiment adds support for querying relations from OpenFGA via GRPC to check resource level permissions as custom builtin commands for Open Policy Agent.

Currently only one command is supported:

openfga.check_permission("SUBJECT","PERMISSION","RESOURCE_ID") -> bool

Build

Note this example uses Go 1.19

go get
go build

Demo

Start openfga demo environment

docker compose -f demo/docker-compose.yml up -d --remove-orphans

Run custom Open Policy Agent with openfga plugin enabled

./custom-opa-openfga run \
  --set plugins.openfga.apiScheme=http \
  --set plugins.openfga.apiHost=localhost:8080 \
  --set plugins.openfga.apiToken=foobar \
  --set plugins.openfga.storeId=ABCD12345678901234567890XX

Create store and import the example data

FGA_API_URL="http://localhost:8080"
FGA_STORE_ID=ABCD12345678901234567890XX
FGA_BEARER_TOKEN=foobar

curl -X POST $FGA_API_URL/stores/$FGA_STORE_ID/authorization-models \
  -H "Authorization: Bearer $FGA_BEARER_TOKEN" \
  -H "content-type: application/json" \
  -d @./demo/schema.json

curl -X POST $FGA_API_URL/stores/$FGA_STORE_ID/write \
  -H "Authorization: Bearer $FGA_BEARER_TOKEN" \
  -H "content-type: application/json" \
  -d '{"writes": { "tuple_keys" : [{"user":"tom","relation":"writer","object":"document:firstdoc"},{"user":"fred","relation":"reader","object":"document:firstdoc"}] }}'

Query relations against openfga See the example schema for reference.

> openfga.check_permission("tom", "view", "document:firstdoc")
true
> openfga.check_permission("tom", "edit", "document:firstdoc")
true
> openfga.check_permission("fred", "edit", "document:firstdoc")
false
> exit

Stop demo environment

docker compose -f demo/docker-compose.yml down