Fixing signing service errors with Document Engine

PSPDFKit Server has been deprecated and replaced by Document Engine. To migrate to Document Engine and unlock advanced document processing capabilities, refer to our migration guide. Learn more about these enhancements on our blog.

Question:

I’m trying to setup a signing service to use with digital signatures. I’m receiving a 500 - Signing service not available error. My SIGNING_SERVICE_URL is pointed at http://localhost:6000/sign and I can confirm that the signing service is up and running. What should I do?

Answer:

If you’re developing your own signing service or running our signing service reference implementation, you need to make sure that you can run the signing service as a sibling container to PSPDFKit Server in the same network.

The simplest way to have things working together is to use a specific directory structure and a unified docker-compose.yml file, so that your application and the signing service sit side by side with the docker-compose.yml definition.

.
├── docker-compose.yml
├── my-app
└── signing-service

The Docker Compose file should have a structure with all 3 services:

services:
  pspdfkit:
    ...
    environment:
      SIGNING_SERVICE_URL: http://signing_service:6000/sign
    depends_on:
      - signing_service
  signing_service:
    build: ./signing-service
    ...
  my_app:
    build: ./my-app
    ...
    depends_on:
      - pspdfkit

Finally, when specifying the SIGNING_SERVICE_URL in your PSPDFKit Server configuration, the URL host has to point to a location reachable by the PSPDFKit Server container.

For this reason, using a URL pointing to localhost cannot work: the PSPDFKit Server container resolves localhost to itself, not to the host machine running the signing service. Instead, the SIGNING_SERVICE_URL should point at the signing_service container.