TDengine

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Overview

A client-mode connector for the TDengine REST API served by taosAdapter (default port 6041). It streams MQTT telemetry into TDengine and runs SQL from MQTT:

Catalog connector event	Endpoint	Notes
POST SQL (INSERT, DDL)	`POST /rest/sql/{db}`	Raw SQL in the body (`text/plain`). Returns `{"code":0,"column_meta":…,"data":…,"rows":n}`.
POST SELECT (rows as objects)	`POST /rest/sql/{db}?row_with_meta=true`	Same SQL endpoint; each row comes back as a JSON object keyed by column name.
POST InfluxDB line write	`POST /influxdb/v1/write?db={db}&precision=ms`	Schemaless InfluxDB line protocol; super tables and columns auto-create. `204` on success.
POST OpenTSDB JSON write	`POST /opentsdb/v1/put/json/{db}`	Schemaless OpenTSDB JSON (`metric`, `timestamp`, `value`, `tags`). `204` on success.
GET ping	`GET /-/ping`	taosAdapter health, `200` (`503` when memory thresholds are exceeded).

Default BASE_ADDRESS is http://YOUR_TDENGINE_HOST:6041. Replace YOUR_DATABASE in the endpoints with your database name; the database must already exist (create it once with CREATE DATABASE IF NOT EXISTS … through the SQL event). Topics use data/tdengine/<object>/<verb>.

Check code in SQL responses. By default taosAdapter answers HTTP 200 even when a SQL statement or the login fails (httpCodeServerError = false). Success is "code": 0; anything else carries the error in desc, for example {"code":855,"desc":"Authentication failure"}. Schemaless writes do return 500 with a JSON error on failure.

Auth

taosAdapter uses HTTP Basic authentication. The connector sets WITH USERNAME and WITH PASSWORD GET SECRET "TDENGINE_PASSWORD", so store the database password as a Hub secret and never commit it. TDengine also accepts Authorization: Taosd <token> (token from GET /rest/login/<user>/<password>) and, on TDengine Cloud, a ?token= query parameter. Change the default root / taosdata credentials on any real deployment.

Basic Syntax

DEFINE ROUTE TdengineRestApi WITH TYPE REST_API
    ADD REST_API_CONFIG
        WITH BASE_ADDRESS "http://YOUR_TDENGINE_HOST:6041"
        WITH ENABLE_CLIENT "true"
        WITH USE_SSL "false"
        WITH REQUEST_TIMEOUT '60'
        WITH DEFAULT_CONTENT_TYPE "application/json"
        WITH USERNAME "root"
        WITH PASSWORD GET SECRET "TDENGINE_PASSWORD"
        # Smoke: GET /-/ping → 200; POST /rest/sql body "SELECT SERVER_VERSION()" → 200 {"code":0,...}.
    ADD EVENT Ping
        WITH SOURCE_TOPIC "data/tdengine/ping"
        WITH DESTINATION_TOPIC "data/tdengine/ping/response"
        WITH METHOD "GET"
        WITH ENDPOINT "/-/ping"
    ADD EVENT ExecSql
        WITH SOURCE_TOPIC "data/tdengine/sql/exec"
        WITH DESTINATION_TOPIC "data/tdengine/sql/exec/response"
        WITH METHOD "POST"
        WITH ENDPOINT "/rest/sql/YOUR_DATABASE"
        WITH HEADERS
            ADD "Content-Type" "text/plain; charset=utf-8"
        WITH BODY "{payload}"
    ADD EVENT QueryRows
        WITH SOURCE_TOPIC "data/tdengine/query/rows"
        WITH DESTINATION_TOPIC "data/tdengine/query/rows/response"
        WITH METHOD "POST"
        WITH ENDPOINT "/rest/sql/YOUR_DATABASE?row_with_meta=true"
        WITH HEADERS
            ADD "Content-Type" "text/plain; charset=utf-8"
            ADD "Accept" "application/json"
        WITH BODY "{payload}"
    ADD EVENT WriteInfluxLine
        WITH SOURCE_TOPIC "data/tdengine/influx/write"
        WITH DESTINATION_TOPIC "data/tdengine/influx/write/response"
        WITH METHOD "POST"
        WITH ENDPOINT "/influxdb/v1/write?db=YOUR_DATABASE&precision=ms"
        WITH HEADERS
            ADD "Content-Type" "text/plain; charset=utf-8"
        WITH BODY "{payload}"
    ADD EVENT WriteOpenTsdbJson
        WITH SOURCE_TOPIC "data/tdengine/opentsdb/write"
        WITH DESTINATION_TOPIC "data/tdengine/opentsdb/write/response"
        WITH METHOD "POST"
        WITH ENDPOINT "/opentsdb/v1/put/json/YOUR_DATABASE"
        WITH HEADERS
            ADD "Content-Type" "application/json"
        WITH BODY "{payload}"

Example MQTT payloads

Create a super table and insert a row (topic data/tdengine/sql/exec). The payload is raw SQL text:

CREATE STABLE IF NOT EXISTS factory_smoke (ts TIMESTAMP, temperature DOUBLE) TAGS (site BINARY(32))

INSERT INTO smoke_porto USING factory_smoke TAGS ('porto') VALUES (NOW, 21.5)

Stream telemetry as line protocol (topic data/tdengine/influx/write):

factory_line,site=porto temperature=22.5 1791234567890

Stream telemetry as OpenTSDB JSON (topic data/tdengine/opentsdb/write):

{ "metric": "factory_otsdb", "timestamp": 1791234567890, "value": 23.5, "tags": { "site": "porto" } }

Query rows (topic data/tdengine/query/rows):

SELECT site, temperature FROM factory_smoke

The response topic receives {"code":0,"column_meta":[…],"data":[{"site":"porto","temperature":21.5}],"rows":1}.

value is a reserved word in TDengine SQL. Name metric columns something like temperature or val when you create tables by hand. Schemaless OpenTSDB writes store the reading in a _value column.

Testing

The factory smoke ran against a local TDengine OSS 3.3.8.4 (taosd plus taosAdapter): GET /-/ping returned 200, CREATE STABLE and INSERT through /rest/sql/coreflux returned 200 with code 0, InfluxDB line and OpenTSDB JSON writes returned 204, and all three rows came back through /rest/sql/coreflux?row_with_meta=true (200, code 0).

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Overview

Auth

Basic Syntax

Example MQTT payloads

Testing

​Overview

​Auth

​Basic Syntax

​Example MQTT payloads

​Testing

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Overview

Auth

Basic Syntax

Example MQTT payloads

Testing

Related