[GitHub] [apisix-dashboard] liuxiran commented on pull request #1812: fix: can not configure upstream with no nodes

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liuxiran commented on pull request #1812:
URL: https://github.com/apache/apisix-dashboard/pull/1812#issuecomment-824998296


   > @liuxiran
   > 
   > How about we make it in the backend? Please see https://github.com/apache/apisix-dashboard/blob/master/api/internal/core/entity/format.go#L49, we can initialize the `nodes` as an empty slice instead of a nil one. Just change `var nodes []*Node` to `nodes := make([]*Node, 0)` .
   > 
   > Looking forward to your insights.
   
   @imjoey Thanks for your advice, and it really make sense for me.
   
   before this change, when get info about an upstream with no nodes
   fe will get
   <img width="834" alt="WechatIMG5" src="https://user-images.githubusercontent.com/2561857/115748640-ee326980-a3c8-11eb-809a-e09e63cd6955.png">
   
   
   actually `nodes:null` causes the problem
   
   after this change, fe will get
   <img width="969" alt="WechatIMG4" src="https://user-images.githubusercontent.com/2561857/115748817-1ae68100-a3c9-11eb-87c6-89c5c9dcd18f.png">
   
   which is matches expectation.
   
   BTW, I have a question in the process of debugging:
   there are some logs I added to watch the changes of `upstream.Nodes` before the advice
   <img width="740" alt="WechatIMG7" src="https://user-images.githubusercontent.com/2561857/115749803-11a9e400-a3ca-11eb-96cc-a6621465ab08.png">
   I found even if I did not do this change, the `upstram.Nodes` will always be `[]`, but what Fe got is different, I haven't thought about it for a long time. 
   
   Also @nic-chen @Jaycean @starsz to take a look, thanks a lot


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