| v0.8.10 | 3.0.5.0 or later | TMQ: Get consuming progress and seek offset to consume. |
| v0.8.12 | 3.0.5.0 or later | TMQ: Get consuming progress and seek offset to consume. |
| v0.8.0 | 3.0.4.0 | Support schemaless insert. |
| v0.7.6 | 3.0.3.0 | Support req_id in query. |
| v0.6.0 | 3.0.0.0 | Base features. |
The Rust Connector is still under rapid development and is not guaranteed to be backward compatible before 1.0. We recommend using TDengine version 3.0 or higher to avoid known issues.
## Installation
## Handling exceptions
After the error is reported, the specific information of the error can be obtained:
```rust
match conn.exec(sql) {
Ok(_) => {
Ok(())
}
Err(e) => {
eprintln!("ERROR: {:?}", e);
Err(e)
}
}
```
## TDengine DataType vs. Rust DataType
TDengine currently supports timestamp, number, character, Boolean type, and the corresponding type conversion with Rust is as follows:
| TDengine DataType | Rust DataType |
| ----------------- | ----------------- |
| TIMESTAMP | Timestamp |
| INT | i32 |
| BIGINT | i64 |
| FLOAT | f32 |
| DOUBLE | f64 |
| SMALLINT | i16 |
| TINYINT | i8 |
| BOOL | bool |
| BINARY | Vec<u8\> |
| NCHAR | String |
| JSON | serde_json::Value |
Note: Only TAG supports JSON types
## Installation Steps
### Pre-installation preparation
* Install the Rust development toolchain
* If using the native connection, please install the TDengine client driver. Please refer to [install client driver](/reference/connector#install-client-driver)
### Add taos dependency
### Install the connectors
Depending on the connection method, add the [taos][taos] dependency in your Rust project as follows:
...
...
@@ -146,7 +182,8 @@ let builder = TaosBuilder::from_dsn("taos://localhost:6030")?;
let conn1 = builder.build();
// use websocket protocol.
let conn2 = TaosBuilder::from_dsn("taos+ws://localhost:6041")?;
let builder2 = TaosBuilder::from_dsn("taos+ws://localhost:6041")?;
let conn2 = builder2.build();
```
After the connection is established, you can perform operations on your database.
...
...
@@ -228,41 +265,183 @@ There are two ways to query data: Using built-in types or the [serde](https://se
"CREATE TABLE `d0` USING `meters` TAGS(0, 'Los Angles')",
]).await?;
}
```
#### SQL Write
### Insert data
<RustInsert />
#### STMT Write
### Query data
<RustQuery />
### execute SQL with req_id
This req_id can be used to request link tracing.
```rust
let rs = taos.query_with_req_id("select * from stable where tag1 is null", 1)?;
```
### Writing data via parameter binding
<RustBind />
#### Schemaless Write
### Schemaless Writing
<RustSml />
### Query data
### Schemaless with req_id
<RustQuery />
This req_id can be used to request link tracing.
## API Reference
```rust
let sml_data = SmlDataBuilder::default()
.protocol(SchemalessProtocol::Line)
.data(data)
.req_id(100u64)
.build()?;
client.put(&sml_data)?
```
### Data Subscription
TDengine starts subscriptions through [TMQ](../../../taos-sql/tmq/).
#### Create a Topic
```rust
taos.exec_many([
// create topic for subscription
format!("CREATE TOPIC tmq_meters with META AS DATABASE {db}")
])
.await?;
```
#### Create a Consumer
You create a TMQ connector by using a DSN.
```rust
let tmq = TmqBuilder::from_dsn("taos://localhost:6030/?group.id=test")?;
```
Create a consumer:
```rust
let mut consumer = tmq.build()?;
```
#### Subscribe to consume data
A single consumer can subscribe to one or more topics.
```rust
consumer.subscribe(["tmq_meters"]).await?;
```
The TMQ is of [futures::Stream](https://docs.rs/futures/latest/futures/stream/index.html) type. You can use the corresponding API to consume each message in the queue and then use `.commit` to mark them as consumed.
```rust
{
let mut stream = consumer.stream();
while let Some((offset, message)) = stream.try_next().await? {
// get information from offset
// the topic
let topic = offset.topic();
// the vgroup id, like partition id in kafka.
let vgroup_id = offset.vgroup_id();
println!("* in vgroup id {vgroup_id} of topic {topic}\n");
if let Some(data) = message.into_data() {
while let Some(block) = data.fetch_raw_block().await? {
// one block for one table, get table name if needed
let name = block.table_name();
let records: Vec<Record> = block.deserialize().try_collect()?;
println!(
"** table: {}, got {} records: {:#?}\n",
name.unwrap(),
records.len(),
records
);
}
}
consumer.commit(offset).await?;
}
}
```
Get assignments:
Version requirements connector-rust >= v0.8.8, TDengine >= 3.0.5.0
### Connector Constructor
```rust
let assignments = consumer.assignments().await.unwrap();
```
#### Assignment subscription Offset
Seek offset:
You create a connector constructor by using a DSN.
Version requirements connector-rust >= v0.8.8, TDengine >= 3.0.5.0
You use the builder object to create multiple connections.
#### Close subscriptions
```rust
let conn: Taos = cfg.build();
consumer.unsubscribe().await;
```
### Connection pooling
The following parameters can be configured for the TMQ DSN. Only `group.id` is mandatory.
- `group.id`: Within a consumer group, load balancing is implemented by consuming messages on an at-least-once basis.
- `client.id`: Subscriber client ID.
- `auto.offset.reset`: Initial point of subscription. *earliest* subscribes from the beginning, and *latest* subscribes from the newest message. The default is earliest. Note: This parameter is set per consumer group.
- `enable.auto.commit`: Automatically commits. This can be enabled when data consistency is not essential.
- `auto.commit.interval.ms`: Interval for automatic commits.
#### Full Sample Code
For more information, see [GitHub sample file](https://github.com/taosdata/TDengine/blob/3.0/docs/examples/rust/nativeexample/examples/subscribe_demo.rs).
### Use with connection pool
In complex applications, we recommend enabling connection pools. [taos] implements connection pools based on [r2d2].
...
...
@@ -292,7 +471,17 @@ In the application code, use `pool.get()? ` to get a connection object [Taos].
let taos = pool.get()?;
```
### Connectors
### More sample programs
The source code of the sample application is under `TDengine/examples/rust` :
For additional troubleshooting, see [FAQ](../../../train-faq/faq).
## API Reference
The [Taos][struct.Taos] object provides an API to perform operations on multiple databases.
...
...
@@ -380,7 +569,7 @@ Note that Rust asynchronous functions and an asynchronous runtime are required.
In addition, this structure is also the entry point for [Parameter Binding](#Parameter Binding Interface) and [Line Protocol Interface](#Line Protocol Interface). Please refer to the specific API descriptions for usage.
### Bind Interface
Bind Interface
Similar to the C interface, Rust provides the bind interface's wrapping. First, the [Taos][struct.taos] object creates a parameter binding object [Stmt] for an SQL statement.
...
...
@@ -391,7 +580,7 @@ stmt.prepare("INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)")?;
The bind object provides a set of interfaces for implementing parameter binding.
#### `.set_tbname(name)`
`.set_tbname(name)`
To bind table names.
...
...
@@ -400,7 +589,7 @@ let mut stmt = taos.stmt("insert into ? values(? ,?)")?;
stmt.set_tbname("d0")?;
```
#### `.set_tags(&[tag])`
`.set_tags(&[tag])`
Bind sub-table table names and tag values when the SQL statement uses a super table.
Bind value types. Use the [ColumnView] structure to create and bind the required types.
...
...
@@ -434,7 +623,7 @@ let params = vec![
let rows = stmt.bind(¶ms)?.add_batch()?.execute()?;
```
#### `.execute()`
`.execute()`
Execute SQL. [Stmt] objects can be reused, re-binded, and executed after execution. Before execution, ensure that all data has been added to the queue with `.add_batch`.
...
...
@@ -449,92 +638,6 @@ stmt.execute()?;
For a working example, see [GitHub](https://github.com/taosdata/taos-connector-rust/blob/main/examples/bind.rs).
### Subscriptions
TDengine starts subscriptions through [TMQ](../../../taos-sql/tmq/).
You create a TMQ connector by using a DSN.
```rust
let tmq = TmqBuilder::from_dsn("taos://localhost:6030/?group.id=test")?;
```
Create a consumer:
```rust
let mut consumer = tmq.build()?;
```
A single consumer can subscribe to one or more topics.
```rust
consumer.subscribe(["tmq_meters"]).await?;
```
The TMQ is of [futures::Stream](https://docs.rs/futures/latest/futures/stream/index.html) type. You can use the corresponding API to consume each message in the queue and then use `.commit` to mark them as consumed.
```rust
{
let mut stream = consumer.stream();
while let Some((offset, message)) = stream.try_next().await? {
// get information from offset
// the topic
let topic = offset.topic();
// the vgroup id, like partition id in kafka.
let vgroup_id = offset.vgroup_id();
println!("* in vgroup id {vgroup_id} of topic {topic}\n");
if let Some(data) = message.into_data() {
while let Some(block) = data.fetch_raw_block().await? {
// one block for one table, get table name if needed
let name = block.table_name();
let records: Vec<Record> = block.deserialize().try_collect()?;
println!(
"** table: {}, got {} records: {:#?}\n",
name.unwrap(),
records.len(),
records
);
}
}
consumer.commit(offset).await?;
}
}
```
Get assignments:
Version requirements connector-rust >= v0.8.8, TDengine >= 3.0.5.0
```rust
let assignments = consumer.assignments().await.unwrap();
```
Seek offset:
Version requirements connector-rust >= v0.8.8, TDengine >= 3.0.5.0
The following parameters can be configured for the TMQ DSN. Only `group.id` is mandatory.
- `group.id`: Within a consumer group, load balancing is implemented by consuming messages on an at-least-once basis.
- `client.id`: Subscriber client ID.
- `auto.offset.reset`: Initial point of subscription. *earliest* subscribes from the beginning, and *latest* subscribes from the newest message. The default is earliest. Note: This parameter is set per consumer group.
- `enable.auto.commit`: Automatically commits. This can be enabled when data consistency is not essential.
- `auto.commit.interval.ms`: Interval for automatic commits.
For more information, see [GitHub sample file](https://github.com/taosdata/TDengine/blob/3.0/docs/examples/rust/nativeexample/examples/subscribe_demo.rs).
For information about other structure APIs, see the [Rust documentation](https://docs.rs/taos).