[DOCKER] Create a program to post to Slack with GO and make it a container

Introduction

Modify the program on the following site to make it a container.

Post to Slack with Go

Folder structure

Configuration to create Docker container for running on raspberry pi Note that github.com/ashwanthkumar/slack-go-webhook has to install curl I can't run it, so install it

./
├── Dockerfile
└── golang
    └── main.go

Dockerfile

FROM multiarch/ubuntu-core:armhf-bionic As builder
RUN apt update &&\
    apt install -y curl gcc git
RUN  curl -OL https://dl.google.com/go/go1.14.4.linux-armv6l.tar.gz
RUN tar -C /usr/local -xzf go1.14.4.linux-armv6l.tar.gz
RUN rm -rf go1.14.4.linux-armv6l.tar.gz
ENV PATH $PATH:/usr/local/go/bin
RUN go get -u github.com/ashwanthkumar/slack-go-webhook
WORKDIR /app
ADD ./golang/ ./
RUN go build -o app
FROM multiarch/ubuntu-core:armhf-bionic
RUN apt-get update && \
    apt-get upgrade -y && \
    apt-get install -y curl && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/* 
WORKDIR /app
COPY --from=builder /app/app /app
COPY ./golang/conf ./
CMD ["./app"]

The program of Pmain.go is borrowed from the link destination The value of WEBHOOKURL can be obtained from the link below Incoming Webhook

main.go

package main

import (
    "github.com/ashwanthkumar/slack-go-webhook"
    "os"
)

const (
    WEBHOOKURL = "https://hooks.slack.com/services/XXXX" //Webhook URL
    CHANNEL    = "dev"  //Destination channel
    USERNAME   = "GoBot" //Display User name
)

func main() {
    PostSlack("HelloWorld!!")
}

func PostSlack(msg string) {
    field1 := slack.Field{Title: "Message", Value: msg}
    field2 := slack.Field{Title: "AnythingKey", Value: "AnythingValue"}

    attachment := slack.Attachment{}
    attachment.AddField(field1).AddField(field2)
    color := "good"
    attachment.Color = &color
    payload := slack.Payload{
        Username:    USERNAME,
        Channel:     CHANNEL,
        Attachments: []slack.Attachment{attachment},
    }
    err := slack.Send(WEBHOOKURL, "", payload)
    if err != nil {
        os.Exit(1)
    }
}

Docker execution

You can post a string to Slack by executing the following command tail.

docker build -t slackpost .
docker run --rm slackpost

As an application of the container, if you add the following code You can change the posting destination from the environment variable.

type SlackSetUp struct {
	WebUrl    string
	Channel   string
	UserName  string
}

func EnvConfRead() SlackSetUp {
	var tmp SlackSetUp
	if str := os.Getenv("SLACK_URL"); str != "" {
		tmp.WebUrl = str
	}
	if str := os.Getenv("SLACK_CHANNEL"); str != "" {
		tmp.Channel = str
	}
	if str := os.Getenv("SLACK_USERNAME"); str != "" {
		tmp.UserName = str
	}
	return tmp
}