[GitHub] Jbalkind commented on issue #3428: Broken resolvers config in apigateway container

[GitBox <gi...@apache.org>]

Jbalkind commented on issue #3428: Broken resolvers config in apigateway container
URL: https://github.com/apache/incubator-openwhisk/issues/3428#issuecomment-417413707
 
 
   I have been seeing this same problem, running OpenWhisk in an Ubuntu 18.04 VM in Qemu. I figured out what's happening and it's not upstream alpine's fault.
   
   The `/etc/api-gateway/conf.d/includes/resolvers.conf` file is creaetd by the incubator-openwhisk-apigateway `init.sh` script, in particular the following line ([see inline](https://github.com/apache/incubator-openwhisk-apigateway/blob/master/init.sh#L58)):
   
   ```
   echo resolver $(awk 'BEGIN{ORS=" "} /nameserver/{print $2}' /etc/resolv.conf | sed "s/ $/;/g") > /etc/api-gateway/conf.d/includes/resolvers.conf
   ```
   
   At the face of it, this seems correct. The problem is that there are comments at the start of the file. They look like this on my system:
   
   ```
   # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
   #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
   # 127.0.0.53 is the systemd-resolved stub resolver.
   # run "systemd-resolve --status" to see details about the actual nameservers.
   ```
   
   The last line of the comment matches the awk command as it contains `nameserver`. Then, as the awk command says, it prints the 2nd token on the line, which is the word `run`.
   
   This can be simply solved by changing the awk command to:
   ```
   awk 'BEGIN{ORS=" "} /^nameserver/{print $2}' /etc/resolv.conf
   ```
   or, for something more robust (in case there's space before `nameserver`), you could go for:
   ```
   awk 'BEGIN{ORS=" "} /^[[:space:]]*nameserver/{print $2}' /etc/resolv.conf
   ```

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