expose external REST API. Failed to load remote configuration

[sandeepamilineni]

Unable to expose external API from a spring boot project using swagger-config.json with below content

To Reproduce
Create 2 Spring Boot 2.3 web projects with springdoc-openapi-ui(1.3.9)

1. Project 1 - create REST APIs. API docs available at http://localhost:8080/v3/api-docs
2. Project 2 - access the openapi docs from Project 1 using swagger-config.json with below content
   located in resources folder

{
  "urls": [
    {
      "url": "http://localhost:8080/v3/api-docs",
      "name": "members"
    }
  ]
}

application.properties for project 2

springdoc.swagger-ui.configUrl=swagger-config.json
server.port=8093
springdoc.cache.disabled= true

Security is not configured for the project
When we access http://localhost:8093/swagger-ui.html
we get error on page "Failed to load remote configuration"
Error snippet below

GET "/swagger-config.json", parameters={}, headers={masked} in DispatcherServlet 'dispatcherServlet'
[nio-8093-exec-3] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to HandlerExecutionChain with [ResourceHttpRequestHandler ["classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/", "/"]] and 3 interceptors
[nio-8093-exec-3] o.s.w.s.r.ResourceHttpRequestHandler     : Resource not found
[nio-8093-exec-3] o.s.web.servlet.DispatcherServlet        : No view rendering, null ModelAndView returned.
 [nio-8093-exec-3] o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND, headers={masked}

Expected behavior
Should be able t view API documentation of project 1 in project 2 when we access http://localhost:8093/swagger-ui.html
Screenshots
getting below error when we access

[bnasslahsen]

Hi @sandeepamilineni,

For serving external Urls, from the same swagger-ui, you need to have CORS enabled, on your applications.

[sandeepamilineni]

Still getting same issue

1. Added below CORS config to external API(project 1).

@Bean
    public WebMvcConfigurer corsConfigurer()
    {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**").allowedOrigins("*");
            }
        };
    }

snippet from logs when accessing external API from project 2

816 TRACE  s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springdoc.webmvc.ui.SwaggerWelcome#redirectToUi(HttpServletRequest)
825 TRACE  .w.s.m.m.a.ServletInvocableHandlerMethod : Arguments: [org.apache.catalina.connector.RequestFacade@1771ebfd]
839 TRACE  o.s.web.servlet.DispatcherServlet        : Rendering view [org.springframework.web.servlet.view.RedirectView: name 'redirect:'; URL [/swagger-ui/index.html?configUrl=swagger-config.json]] 
839 DEBUG  o.s.web.servlet.view.RedirectView        : View name 'redirect:', model {}
839 DEBUG  o.s.web.servlet.DispatcherServlet        : Completed 302 FOUND, headers={masked}
907 TRACE  o.s.web.servlet.DispatcherServlet        : GET "/swagger-ui/swagger-config.json", parameters={}, headers={masked} in DispatcherServlet 'dispatcherServlet'
910 TRACE  o.s.w.s.handler.SimpleUrlHandlerMapping  : Matching patterns [/**/swagger-ui/**, /**]
910 TRACE  o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to HandlerExecutionChain with [ResourceHttpRequestHandler ["classpath:/META-INF/resources/webjars/"]] and 3 interceptors
911 DEBUG  o.s.w.s.r.ResourceHttpRequestHandler     : Resource not found
912 TRACE  o.s.web.servlet.DispatcherServlet        : No view rendering, null ModelAndView returned.
912 DEBUG  o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND, headers={masked}
915 TRACE  o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/error", parameters={}, headers={masked} in DispatcherServlet 'dispatcherServlet'
916 TRACE  s.w.s.m.m.a.RequestMappingHandlerMapping : 2 matching mappings: [{ /error}, { /error, produces [text/html]}]
916 TRACE  s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#error(HttpServletRequest)
917 TRACE  .w.s.m.m.a.ServletInvocableHandlerMethod : Arguments: [org.apache.catalina.core.ApplicationHttpRequest@4bfdebb2]
930 DEBUG  o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Using 'application/json', given [*/*] and supported [application/json, application/*+json, application/json, application/*+json]
930 TRACE  o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Writing [{timestamp=Sat May 23 21:58:19 IST 2020, status=404, error=Not Found, message=, path=/swagger-ui/swagger-config.json}]
956 TRACE  o.s.web.servlet.DispatcherServlet        : No view rendering, null ModelAndView returned.
956 DEBUG  o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 404, headers={masked}
958 TRACE  o.s.web.servlet.DispatcherServlet        : GET "/swagger-ui/swagger-config.json", parameters={}, headers={masked} in DispatcherServlet 'dispatcherServlet'
959 TRACE  o.s.w.s.handler.SimpleUrlHandlerMapping  : Matching patterns [/**/swagger-ui/**, /**]
959 TRACE  o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to HandlerExecutionChain with [ResourceHttpRequestHandler ["classpath:/META-INF/resources/webjars/"]] and 3 interceptors
959 DEBUG  o.s.w.s.r.ResourceHttpRequestHandler     : Resource not found
959 TRACE  o.s.web.servlet.DispatcherServlet        : No view rendering, null ModelAndView returned.
959 DEBUG  o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND, headers={masked}
959 TRACE  o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/error", parameters={}, headers={masked} in DispatcherServlet 'dispatcherServlet'
960 TRACE  s.w.s.m.m.a.RequestMappingHandlerMapping : 2 matching mappings: [{ /error}, { /error, produces [text/html]}]
960 TRACE  s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#error(HttpServletRequest)
960 TRACE  .w.s.m.m.a.ServletInvocableHandlerMethod : Arguments: [org.apache.catalina.core.ApplicationHttpRequest@6038ba5b]
960 DEBUG  o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Using 'application/json', given [*/*] and supported [application/json, application/*+json, application/json, application/*+json]
960 TRACE  o.s.w.s.m.m.a.HttpEntityMethodProcessor  : Writing [{timestamp=Sat May 23 21:58:19 IST 2020, status=404, error=Not Found, message=, path=/swagger-ui/swagger-config.json}]
961 TRACE  o.s.web.servlet.DispatcherServlet        : No view rendering, null ModelAndView returned.
961 DEBUG  o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 404, headers={masked}

[bnasslahsen]

@sandeepamilineni,

It should be better if you set:

springdoc.swagger-ui.configUrl=/swagger-config.json

No ?

[sandeepamilineni]

Not working

[bnasslahsen]

You should make sure your swagger-config.json is located to in static folder (standard spring configuration). In your IDE it (src/main/resrouces/static)

Is it your case ?

[sandeepamilineni]

great, Its working after placing swagger-config.json in src/main/resrouces/static folder.

Thank you

[arslanakhtar61]

It's also working for me after placing swagger-config.json in src/main/resources/static folder in Project 2.
Also it's important to add prefix with "/" otherwise it doesn't work

springdoc.swagger-ui.configUrl=/swagger-config.json #works
springdoc.swagger-ui.configUrl=swagger-config.json # doesn't works

content of swagger-config.json placed inside src/main/resources/static folder in Project 2

{
  "urls": [
    {
      "url": "http://localhost:8080/v3/api-docs",
      "name": "members"
    }
  ]
}

Thank you