Express Gateway - Proxy request with Bearer Token - express-gateway

Question

I am trying to figure out how to get Express Gateway to use the Auth Bearer token in request, upstream to the api service.
Below is my config as of right now.
http:
port: 8080
admin:
port: 9876
host: localhost
apiEndpoints:
api:
host: localhost
paths:
- '/truck-api/*'
- '/car-api/*'
serviceEndpoints:
truck-service:
url: 'http://10.0.0.2:5010/api'
car-service:
url: 'http://10.0.0.2:5011/api'
policies:
- basic-auth
- cors
- expression
- key-auth
- log
- oauth2
- proxy
- rate-limit
- rewrite
- request-transformer
pipelines:
default:
apiEndpoints:
- api
policies:
- proxy:
-
condition:
name: pathMatch
pattern: "^/truck-api/(.*)"
action:
serviceEndpoint: truck-service
prependPath: true
ignorePath: false
stripPath: true
changeOrigin: true
-
condition:
name: pathMatch
pattern: "^/car-api/(.*)"
action:
serviceEndpoint: car-service
prependPath: true
ignorePath: false
stripPath: true
changeOrigin: true
The frontend calls express gateway with a proper auth bearer token, however the express gateway doesn't forward that auth bearer token on to the upstream service.
Advice?

Answer 1

After some digging and a lot of trial and error the solution was relatively simple, use request transformer.
added this to the policies section:
- request-transformer:
- action:
headers:
remove: ['Authorization']
add:
Authorization: "'Bearer ***'"

Answer 2

For me remove: ['Authorization'] did not work.
I was authenticating towards express gateway using:
"Authorization: apiKey ${keyId}:${keySecret}" and authenticating towards backend service by using Authorization: "'Bearer ***'" added by request-transformer. I would expect remove: ['Authorization'] would remove "Authorization: apiKey ${keyId}:${keySecret}", after I was already successfully authenticated at express gateway and add: Authorization: "'Bearer ***'" would add new Authorization header so newly constructed request would replace apiKey with Bearer token but using remove: ['Authorization'] resulted in failure to authenticate at express gateway.
I resolved this issue by changing HTTP header used for authorization at express gateway side with apiKeyHeader (https://www.express-gateway.io/docs/policies/key-authorization/).
policies:
- request-transformer:
- action:
headers:
add:
# pass oauth2 token
Authorization: "'Bearer ***'"
- key-auth:
- action:
# arbitrarily rename default header name from Authorization
apiKeyHeader: open_sesame
The open_sesame header grants us access to api gateway and request-transformer adds authorization header with proper token to the request for accessing the backend service.
curl -v -H "open_sesame: apiKey ${keyId}:${keySecret}"...