How to run a Go function with redis package on OpenWhisk? - go

Question

I am having some troubles to run a golang package on OpenWhisk (IBM Cloud Functions).
I ran the following on my local computer and it works without any problems (go run sample.go):
package main
import (
"fmt"
"encoding/json"
"github.com/go-redis/redis"
)
func main() {
var redisClient *redis.Client = redis.NewClient(&redis.Options{
Addr: "...",
Password: "...",
DB: 0,
})
redisClient.Set("foo", "bar", 0)
defer redisClient.Close()
msg := map[string]string{"msg": ("Done !")}
res, _ := json.Marshal(msg)
fmt.Println(string(res))
}
But i didn't find any way to make it working on OpenWhisk. I ran the following:
GOOS=linux GOARCH=amd64 go build -o exec sample.go
zip exec.zip exec
bx wsk action update myfunction --native exec.zip
bx wsk action invoke myfunction -r
bx wsk activation logs --last --strip
"error": "The action did not return a dictionary."
"2018-02-21T01:21:05.962244788Z stdout: [Errno 2] No such file or
directory: '/action/exec'"
The problem is related to the github.com/go-redis/redis package, when i remove it and its code then the function is running well. I met the same problem with the mgo package (MongoDB)...
I am new in Golang so it may be obvious, but for now i am stuck :/

Answer 1

The binary in the zip file is dynamically linked against shared libraries not available on the platform.
Using file and ldd confirms this:
$ file exec
exec: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, not stripped
$ ldd exec
/lib64/ld-linux-x86-64.so.2 (0x7f3f63f10000)
libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x7f3f63f10000)
libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7f3f63f10000)
Build a static binary or build a dynamically linked binary inside the Docker image used by the platform (openwhisk/dockerskeleton).
The file not found error is misleading but reported by bash when executing files with this issue.

Answer 2

"error": "The action did not return a dictionary."
This is an open wsk error message.
It means that you did not return a dictionary on stdout
below is a valid return as it returns a json object
{"error":"something broke!"}
below would be invalid
"something broke!"
suggestions: check to see if there is any errors when you build ( normally )
the file in your dropbox doesnt look like a binary file...I suggest checking you can build the binary first