A simple Bash script that can be used to send Slack messages via curl to a Slack Channel using the Slack Block API.

slack.sh

#!/bin/bash

SLACK_CHANNEL="automation"
SLACK_URL="https://slack.com/api/chat.postMessage"
AS_USER=true

slackMsgHeaderBlock=$(
jq -n '{
  type: "rich_text",
  elements: [
    {
      type: "rich_text_section",
      elements: [
        {
          "type": "emoji",
          "name": "rotating_light"
        },
        {
          type: "text",
          text: " "
        },
        {
          type: "text",
          style: {
            bold: true,
          },
          text: "Triage Required."
        },
        {
          type: "text",
          text: " "
        },
        {
          type: "text",
          text: "E2E could not be started."
        },
        {
          type: "text",
          text: " "
        },
        {
          "type": "link",
          "url": "https://google.com",
          "text": "View log."
        }
      ]
    }
  ]
}'
)
slackMsgPayload=$(jq -c -n \
    --arg channel "$SLACK_CHANNEL" \
    --arg blocks "[$slackMsgHeaderBlock]" \
    --argjson as_user "$AS_USER" \
    '$ARGS.named'
)
slackMsgResponse=$(curl -s -X POST -H "Authorization: Bearer $TOKEN" -H "Content-type: application/json" -d "$slackMsgPayload" "$SLACK_URL")
slackThreadTs=$(jq -r '.message.ts' <<< "${slackMsgResponse}")

slackMsgThreadedBlocks=$(
jq -n '{
  type: "rich_text",
  elements: [
    {
      type: "rich_text_section",
      elements: [
        {
          type: "text",
          text: "Check the following:"
        }
      ]
    },
    {
      type: "rich_text_list",
      style: "bullet",
      elements: [
        {
          type: "rich_text_section",
          elements: [
            {
              type: "text",
              text: "Action item #1."
            }
          ]
        },
        {
          type: "rich_text_section",
          elements: [
            {
              type: "text",
              text: "Action item #2."
            }
          ]
        }
      ]
    }
  ]
}'
)
slackThreadedMsgPayload=$(jq -c -n \
    --arg channel "$SLACK_CHANNEL" \
    --arg blocks "[$slackMsgThreadedBlocks]" \
    --arg thread_ts "$slackThreadTs" \
    --argjson as_user "$AS_USER" \
    '$ARGS.named'
)
slackThreadedMsgResponse=$(curl -s -X POST -H "Authorization: Bearer $TOKEN" -H "Content-type: application/json" -d "$slackThreadedMsgPayload" "$SLACK_URL")