notify-slack

#!/usr/bin/env bash
set -euo pipefail

: "${SLACK_TOKEN:?The SLACK_TOKEN environment variable is required.}"
: "${SLACK_CHANNELS:?The SLACK_CHANNELS environment variable is required.}"

upload=0
output=/dev/null
thread_ts=""
broadcast=0
fail_on_error=0
args=()

for arg; do
    case "$arg" in
        --upload)
            upload=1;;
        --output=*)
            output="${arg#*=}";;
        --thread-ts=*)
            thread_ts="${arg#*=}";;
        --broadcast)
            broadcast=1;;
        --fail-on-error)
            fail_on_error=1;;
        *)
            args+=("$arg");;
    esac
done

set -- "${args[@]}"

text="${1:?Some message text is required.}"

send_slack_message() {
    if [[ "$upload" == 1 ]]; then
        echo "Uploading data to Slack with the message: $text"

        upload_file="$(mktemp -t upload-file-XXXXXX)"
        trap "rm -f '$upload_file'" EXIT

        cat /dev/stdin > "$upload_file"
        # printf used to strip whitespace from output of macOS/BSD wc
        # See <https://github.com/nextstrain/ingest/pull/47#discussion_r1974802967>
        length=$(printf '%d' "$(<"$upload_file" wc -c)")

        upload_info=$(curl https://slack.com/api/files.getUploadURLExternal \
            --header "Authorization: Bearer $SLACK_TOKEN" \
            --form-string filename="$text" \
            --form-string length="$length" \
            --fail --silent --show-error \
            --http1.1 )

        upload_url="$(jq -r .upload_url <<< "$upload_info")"
        curl "$upload_url" \
            --form-string filename="$text" \
            --form file="@$upload_file" \
            --fail --silent --show-error \
            --http1.1 > /dev/null

        files_uploaded="$(jq -r "[{id: .file_id}]" <<< "$upload_info")"
        curl -X POST https://slack.com/api/files.completeUploadExternal \
            --header "Authorization: Bearer $SLACK_TOKEN" \
            --form-string channel_id="$SLACK_CHANNELS" \
            --form-string thread_ts="$thread_ts" \
            --form-string files="$files_uploaded" \
            --fail --silent --show-error \
            --http1.1 \
            --output "$output"

    else
        echo "Posting Slack message: $text"
        curl https://slack.com/api/chat.postMessage \
            --header "Authorization: Bearer $SLACK_TOKEN" \
            --form-string channel="$SLACK_CHANNELS" \
            --form-string text="$text" \
            --form-string thread_ts="$thread_ts" \
            --form-string reply_broadcast="$broadcast" \
            --fail --silent --show-error \
            --http1.1 \
            --output "$output"
    fi
}

if ! send_slack_message; then
    if [[ "$fail_on_error" == 1 ]]; then
        echo "Sending Slack message failed"
        exit 1
    else
        echo "Sending Slack message failed, but exiting with success anyway."
        exit 0
    fi
fi