experiment with slack message

slack/slack.go

@@ -3,6 +3,7 @@ package slack
 import (
 	"fmt"
 	"log"
+	"os"
 	"strings"
 
 	"github.com/dustin/go-humanize"
@@ -25,16 +26,49 @@ func New(token, channel string, logger *log.Logger) *Notifier {
 }
 
 func (n *Notifier) Notify(r usage.Report) error {
+	host, err := os.Hostname()
+	if err != nil {
+		log.Printf("Failed to get hostname %v", err)
+	}
+
+	msg := n.Message(r, host)
+
+	// TODO should we use a context? What is the default behavior, does posting
+	// the message ever time out?
+	_, _, err = n.client.PostMessage(n.channel, msg)
+	log.Printf("Posted slack message on channel")
+
+	return err
+}
+
+func (n *Notifier) Message(r usage.Report, host string) slack.MsgOption {
+	// TODO clean up code
+	header := "Disk usage report"
+	if host != "" {
+		header = header + fmt.Sprintf(" for host %q", host)
+	}
+	headerText := slack.NewTextBlockObject("plain_text", header, false, false)
+	headerSection := slack.NewSectionBlock(headerText, nil, nil)
+
+	limitImage := slack.NewImageBlockElement("https://api.slack.com/img/blocks/bkb_template_images/notificationsWarningIcon.png", "notifications warning icon")
+	limitHeader := slack.NewTextBlockObject("mrkdwn", fmt.Sprintf("*Following disks have reached the usage limit of %d%%*", r.Limits[0].Limit), false, false)
+
 	var sb strings.Builder
 	for _, l := range r.Limits {
-		fmt.Fprintf(&sb, "Free/Total %s/%s %q - reached limit of %d%%\n", humanize.Bytes(l.Free), humanize.Bytes(l.Total), l.Path, l.Limit)
+		fmt.Fprintf(&sb, "• %q - %s/%s (free/total)\n", l.Path, humanize.Bytes(l.Free), humanize.Bytes(l.Total))
 	}
+	// TODO split errors into own section?
 	for _, e := range r.Errors {
 		sb.WriteString(e.Error())
 	}
-	_, _, err := n.client.PostMessage(
-		n.channel, slack.MsgOptionText(sb.String(), false),
+	rest := slack.NewTextBlockObject("mrkdwn", sb.String(), false, false)
+	restSection := slack.NewSectionBlock(rest, nil, nil)
+
+	limitSection := slack.NewContextBlock(
+		"",
+		[]slack.MixedElement{limitImage, limitHeader}...,
 	)
-	log.Printf("Posted slack message on channel")
-	return err
+	divSection := slack.NewDividerBlock()
+
+	return slack.MsgOptionBlocks(headerSection, divSection, limitSection, restSection)
 }