Posting a Slack message from Travis CI

build.sh

# Environment variables
REPO=${TRAVIS_REPO_SLUG}
BRANCH=${TRAVIS_BRANCH}
COMMIT_HASH=${TRAVIS_COMMIT}
COMMIT_HASH_SHORT=${COMMIT_HASH:0:7}
COMMIT_MESSAGE=${TRAVIS_COMMIT_MESSAGE}
IS_PULL_REQUEST=${TRAVIS_PULL_REQUEST}
BUILD_DIR=${TRAVIS_BUILD_DIR}
BUILD_NUMBER=${TRAVIS_BUILD_NUMBER}
BUILD_URL=${TRAVIS_BUILD_WEB_URL}

function sendAlertToSlack {
    if (($# != 3)); then echo "Please pass webhook, download URL, and build number!"; exit 2; fi
    SLACK_WEBHOOK=$1
    DOWNLOAD_URL=$2
    DEBUGGABLE=$3

    HTTP_RESPONSE=$(curl --silent --write-out "HTTPSTATUS:%{http_code}" \
        --header "Content-type: application/json" \
        --request POST \
        --data \
        "{
   \"blocks\":[
      {
         \"type\":\"section\",
         \"text\":{
            \"type\":\"mrkdwn\",
            \"text\":\"*$BRANCH build (#$BUILD_NUMBER) available on devices!*\n*Message:* $COMMIT_MESSAGE\"
         }
      },
      {
         \"type\":\"section\",
         \"fields\":[
            {
               \"type\":\"mrkdwn\",
               \"text\":\"*Debuggable:*\n$DEBUGGABLE\"
            },
            {
               \"type\":\"mrkdwn\",
               \"text\":\"*Hash:*\n$COMMIT_HASH_SHORT\"
            }
         ]
      },
      {
         \"type\":\"actions\",
         \"elements\":[
            {
               \"type\":\"button\",
               \"text\":{
                  \"type\":\"plain_text\",
                  \"text\":\"Install\"
               },
               \"value\":\"internal-app-sharing\",
               \"url\":\"$DOWNLOAD_URL\"
            },
            {
               \"type\":\"button\",
               \"text\":{
                  \"type\":\"plain_text\",
                  \"text\":\"Help\"
               },
               \"value\":\"help\",
               \"url\":\"https://support.google.com/googleplay/android-developer/answer/9303479#on\"
            },
            {
               \"type\":\"button\",
               \"text\":{
                  \"type\":\"plain_text\",
                  \"text\":\"Travis\"
               },
               \"value\":\"travis\",
               \"url\":\"$BUILD_URL\"
            },
            {
               \"type\":\"button\",
               \"text\":{
                  \"type\":\"plain_text\",
                  \"text\":\"GitHub\"
               },
               \"value\":\"github\",
               \"url\":\"https://github.com/$REPO/commit/$COMMIT_HASH\"
            }
         ]
      }
   ]
}" \
      "$SLACK_WEBHOOK")
    HTTP_BODY=$(echo ${HTTP_RESPONSE} | sed -e 's/HTTPSTATUS\:.*//g')
    HTTP_STATUS=$(echo ${HTTP_RESPONSE} | tr -d '\n' | sed -e 's/.*HTTPSTATUS://')
    if [[ ${HTTP_STATUS} != 200 ]]; then
      echo -e "Sending Slack notification failed.\nStatus: $HTTP_STATUS\nBody: $HTTP_BODY\nExiting."
      exit 1
    fi
}