Wrong build instructions?

[Grégoire Paris]

I don't know go or rocker but I'm trying to contribute a solution to #68 , and I am stuck :

if git describe --contains HEAD &>/dev/null; then export VERSIONARGS="-var DNSDockVersion=`git describe --contains HEAD`"; else unset VERSIONARGS; fi
echo $VERSIONARGS
-var DNSDockVersion=v1.13.1
rocker build -var Arch=amd64 ${VERSIONARGS} -var OutputDir=/tmp  
Incorrect Usage.

NAME:
   build - launches a build for the specified Rockerfile

USAGE:
   command build [command options] [arguments...]

OPTIONS:
   --file, -f "Rockerfile"              rocker build file to execute
   --auth, -a                       Username and password in user:password format
   --build-arg [--build-arg option --build-arg option]  Set build-time variables, can pass multiple of those, format is key=value (default [])
   --var [--var option --var option]            set variables to pass to build tasks, value is like "key=value"
   --vars [--vars option --vars option]         Load variables form a file, either JSON or YAML. Can pass multiple of this.
   --no-cache                       supresses cache for docker builds
   --reload-cache                   removes any cache that hit and save the new one
   --cache-dir "~/.rocker_cache"            Set the directory where the cache will be stored
   --no-reuse                       suppresses reuse for all the volumes in the build
   --push                       pushes all the images marked with push to docker hub
   --pull                       always attempt to pull a newer version of the FROM images
   --attach                     attach to a container in place of ATTACH command
   --meta                       add metadata to the tagged images, such as user, Rockerfile source, variables and git branch/sha
   --print                      just print the Rockerfile after template processing and stop
   --demand-artifacts                   fail if artifacts not found for {{ image }} helpers
   --id                         override the default id generation strategy for current build
   --artifacts-path                     put artifacts (files with pushed images description) to the directory
   --no-garbage                     remove the images from the tail if not tagged
   --push-retry "0"                 number of retries for failed image pushes

flag provided but not defined: -var DNSDockVersion%

The last line looks interesting. What did I do wrong?

[Alexandre Acebedo]

Hi
Are you sure docker is installed ?
If it is the case, can you try the following command:

cd <path_to_your code>
rocker build -var SRCDIR=. -var OUTPUTDIR=/tmp/output

You shall find a binary in /tmp/output

[Grégoire Paris]

Are you sure docker is installed ?

Yes (I use it for my day to day work)

rocker build -var SRCDIR=. -var OUTPUTDIR=/tmp/output

Seems to work! Thanks!

[Grégoire Paris]

Hm… my changes don't seem to be taken into account. I can't use the binary since I already have a DNS server running, so I thought I'd just run the container that was used for building… not sure if it makes sense. I run it like that :

docker run --rm --volume=/var/run/docker.sock:/var/run/docker.sock --publish=172.17.0.1:53:53/udp --name dns_dock_dev tonistiigi/dnsdock:amd64-develop

Does it make sense?

[Alexandre Acebedo]

you can avoid the --publish and get the IP of your container (docker inspect dns_dock_dev). Add this IP as a new DNS server in your /etc/resolv.conf (first line) and use "dig" to see the name resolution.

[Grégoire Paris]

you can avoid the --publish and get the IP of your container (docker inspect dns_dock_dev). Add this IP as a new DNS server in your /etc/resolv.conf (first line) and use "dig" to see the name resolution.

Yeah but the IP might change from time to time, right? At least that way I have it fixed. Anyway regarding my question, once I have run rocker, is this command I run a good way to test my changes? If yes, do you have any idea why they seem to have no effect ?

Here is the diff :

diff --git a/src/http.go b/src/http.go
index 6dcecdd..f33369f 100644
--- a/src/http.go
+++ b/src/http.go
@@ -41,10 +41,13 @@ func (s *HTTPServer) Start() error {
 }

 func (s *HTTPServer) getServices(w http.ResponseWriter, req *http.Request) {
+       log.Println('hello');
        if err := json.NewEncoder(w).Encode(s.list.GetAllServices()); err != nil {
                log.Println("Error encoding: ", err)
                http.Error(w, err.Error(), http.StatusInternalServerError)
+               return
        }
+       w.Header().Set("Content-Type", "application/json")
 }

 func (s *HTTPServer) getService(w http.ResponseWriter, req *http.Request) {

I added the log afterwards, but couldn't see it in the output, and I'm unsure what I need to do to have the new code running, so I try running the rocker command again but it went pretty past.

[Alexandre Acebedo]

Yep the container's IP may change (if you change the starting order of all your containers)
The instruction I gave you was just test it. If you want to use it in production you shall type -p 53:53.
this command is a good way to test. Your changes shall have an effect. You don't see the "hello" log ?

[Grégoire Paris]

No I don't, but I added it afterwards, maybe I need to recompile something? I don't know go at all.

[Alexandre Acebedo]

rerun the rocker build command with --no-cache. It your connection is too slow, rerun rocker build with --attach and run the following command in the container:
go build -o /tmp/output/dnsdock

[Grégoire Paris]

It seems to work, I have some error output related to my code :)

[Grégoire Paris]

Changed the single with double quotes and I can see my code in action, thanks a lot!