library_server_messaging_slack

Posts messages to Slack from @thzero/library_server, using @slack/web-api.

Intended for operational notices — a deploy finished, a job failed, a threshold was crossed. It is not a chat integration and does not receive anything from Slack.

Requirements

NodeJs

NodeJs version 22+

Slack

A Slack app with a bot token:

• Create an app at api.slack.com/apps
• Under OAuth & Permissions, add the chat:write bot token scope
• Install the app to the workspace and copy the Bot User OAuth Token (xoxb-…)
• Invite the bot to each channel you intend to post to — chat.postMessage fails with not_in_channel otherwise

Installation

npm install @thzero/library_server_messaging_slack

Peer dependencies

• @thzero/library_common
• @thzero/library_common_service
• @thzero/library_server

What it provides

index.js — default export MessagingService, extending Service.

| Method | Purpose | |---|---| | init(injector) | Reads the token from config and builds the WebClient. A failure here is logged, not thrown — the service stays constructed but unusable. | | message(correlationId, channel, message) | Posts message to channel via chat.postMessage. Returns a success response, or an error response carrying the correlationId when Slack rejects it. |

message never throws. A Slack outage produces a failed response and a logged exception rather than taking down the caller.

Configuration

{
    "app": {
        "messaging": {
            "slack": {
                "token": "xoxb-<bot user oauth token>"
            }
        }
    }
}

Keep the token out of source control — supply it from an environment variable through config/custom-environment-variables.json, the same way the database connection is handled.

Wiring it up

Register it with the injector from _initServices in your BootMain derived class, or from a boot plugin's initServices, then resolve it where you need it:

const serviceMessaging = injector.getService(AppConstants.InjectorKeys.SERVICE_MESSAGING_SLACK);
await serviceMessaging.message(correlationId, '#ops', `Deploy ${version} completed.`);

channel accepts either a channel name (#ops) or a channel ID (C0123456789). An ID is more robust — a renamed channel keeps its ID.

Development

npm run lint       # eslint .
npm run lint:fix   # eslint . --fix
npm test           # node --test "test/*.test.js"