observe-events

Observe Events

Observe events in real time from an EventSourcingDB instance. This opens a long-lived streaming connection.

Configuration

Read configuration from environment variables:

echo "ESDB_URL: ${ESDB_URL:-http://localhost:3000}"
echo "ESDB_API_TOKEN: ${ESDB_API_TOKEN:-(not set)}"

• Use ESDB_URL if set, otherwise default to http://localhost:3000.
• If ESDB_API_TOKEN is not set, use AskUserQuestion to ask the user for the API token.

Request

This endpoint returns a long-lived NDJSON stream. Always use --max-time to ensure the connection terminates (default: 30 seconds). Use --no-buffer and filter out heartbeats:

curl -s --no-buffer --max-time 30 -X POST \
  -H "authorization: Bearer ${ESDB_API_TOKEN}" \
  -H "content-type: application/json" \
  -d '<REQUEST_BODY>' \
  "${ESDB_URL:-http://localhost:3000}/api/v1/observe-events" \
  | grep -v '"type":"heartbeat"'

When the user wants a custom timeout, use AskUserQuestion to ask for the desired duration in seconds.

Request Body

{
  "subject": "/<subject-path>",
  "options": {
    "recursive": false,
    "lowerBound": {
      "id": "<event-id>",
      "type": "exclusive"
    },
    "fromLatestEvent": {
      "subject": "/<subject-path>",
      "type": "<event-type>",
      "ifEventIsMissing": "read-everything"
    }
  }
}

Options:

• recursive (boolean): Include sub-subjects.
• lowerBound: Resume from event ID. type: "inclusive" or "exclusive".
• fromLatestEvent: Start from last event of given type. ifEventIsMissing: "read-everything" or "wait-for-event". Cannot be combined with lowerBound.

Example

curl -s --no-buffer --max-time 30 -X POST \
  -H "authorization: Bearer ${ESDB_API_TOKEN}" \
  -H "content-type: application/json" \
  -d "{
    \"subject\": \"/\",
    \"options\": {
      \"recursive\": true
    }
  }" \
  "${ESDB_URL:-http://localhost:3000}/api/v1/observe-events" \
  | grep -v '"type":"heartbeat"'

Response

NDJSON stream with one line per event:

{"type":"event","payload":{...}}

Heartbeats ({"type":"heartbeat","payload":{}}) are sent periodically and are filtered out by the grep -v pattern.

Conventions

• Subjects always start with / (e.g., /books/42).
• Event IDs and bound IDs are strings (e.g., "42").