Postgraphile -“必须提供查询根”错误消息

Question

我们已经有了一个包含数据的postgresql数据库，并且我们正在试验postgraphile作为graphql API。我们遇到了一个让我们摸不着头脑的错误。服务器运行得很好，但我们得到了以下信息：

postgraphile -c postgres://username:password@localhost:5432/my_db                                                                

PostGraphile server listening on port 5000                                                                                                                 

  ‣ Connected to Postgres instance postgres://localhost:5432/my_db                                                                                          
  ‣ Introspected Postgres schema(s) public                                                                                                                      
  ‣ GraphQL endpoint served at http://localhost:5000/graphql                                                                                                    
  ‣ GraphiQL endpoint served at http://localhost:5000/graphiql                                                                                                  

* * *                                                                                                                                                           

An error occurred, it might be okay but it doesn't look like the error we were expecting... run with envvar 'DEBUG="graphile-build:warn"' to view the error     
An error occurred, it might be okay but it doesn't look like the error we were expecting... run with envvar 'DEBUG="graphile-build:warn"' to view the error     

Error: Query root type must be provided.                                                                                                                        
    at assertValidSchema (C:\Users\user\AppData\Roaming\npm\node_modules\postgraphile\node_modules\graphql\type\validate.js:78:11)                      
    at Object.validate (C:\Users\user\AppData\Roaming\npm\node_modules\postgraphile\node_modules\graphql\validation\validate.js:61:35)                  
    at parseQuery (C:\Users\user\AppData\Roaming\npm\node_modules\postgraphile\build\postgraphile\http\createPostGraphileHttpRequestHandler.js:208:48)  
    at Promise.all.paramsList.map (C:\Users\user\AppData\Roaming\npm\node_modules\postgraphile\build\postgraphile\http\createPostGraphileHttpRequestHandler.js:469:63)                                                                                                                                                  
    at Array.map (<anonymous>)                                                                                                                                  
    at requestHandler (C:\Users\user\AppData\Roaming\npm\node_modules\postgraphile\build\postgraphile\http\createPostGraphileHttpRequestHandler.js:435:52)                                                                                                                                   
    at <anonymous>                                                                                                                                              
    at process._tickCallback (internal/process/next_tick.js:188:7) 

当我们导航到localhost:500/graphiql时，我们在文档资源管理器中看到一个"no schema available“。

查询根是public模式吗？或者我们错过了什么？

Answer 1

较新版本的PostGraphile有更有用的错误消息，通常包括建议的解决方案。类似上述的“发生错误”错误现在还包含有助于诊断的潜在错误的预览。

这里有关于如何设置DEBUG环境变量的说明：https://www.graphile.org/postgraphile/debugging/#debug-envvars

下面是你在Linux、macOS或Windows中如何做到这一点：

# Bash (Linux, macOS, etc)
export DEBUG="graphile-build:warn" postgraphile -c postgres://username:password@localhost:5432/my_db

# Windows Console
set DEBUG=graphile-build:warn & postgraphile -c postgres://username:password@localhost:5432/my_db

# Windows PowerShell
$env:DEBUG = "graphile-build:warn"; postgraphile -c postgres://username:password@localhost:5432/my_db