From ef845842f8a02af544bb56d76635b9f6ce923e3b Mon Sep 17 00:00:00 2001 From: sheyanjie-qq <249478495@qq.com> Date: Mon, 12 Aug 2024 17:29:17 +0800 Subject: [PATCH 1/3] mod rust log --- .../rust/nativeexample/examples/connect.rs | 18 ++- .../rust/nativeexample/examples/createdb.rs | 35 +++++ .../rust/nativeexample/examples/insert.rs | 31 +++++ .../rust/nativeexample/examples/query.rs | 129 +++++++++--------- .../rust/nativeexample/examples/schemaless.rs | 27 +++- .../rust/nativeexample/examples/stmt.rs | 19 ++- .../rust/nativeexample/examples/tmq.rs | 79 +++++++---- .../rust/restexample/examples/connect.rs | 18 ++- .../rust/restexample/examples/createdb.rs | 35 +++++ .../rust/restexample/examples/insert.rs | 31 +++++ .../rust/restexample/examples/query.rs | 102 ++++++++++++++ .../rust/restexample/examples/schemaless.rs | 27 +++- .../rust/restexample/examples/stmt.rs | 21 +-- .../examples/rust/restexample/examples/tmq.rs | 79 +++++++---- docs/zh/08-develop/02-sql.md | 4 +- .../taosdata/example/ConsumerLoopFull.java | 18 +-- .../taosdata/example/WsConsumerLoopFull.java | 16 +-- 17 files changed, 521 insertions(+), 168 deletions(-) create mode 100644 docs/examples/rust/nativeexample/examples/createdb.rs create mode 100644 docs/examples/rust/nativeexample/examples/insert.rs create mode 100644 docs/examples/rust/restexample/examples/createdb.rs create mode 100644 docs/examples/rust/restexample/examples/insert.rs create mode 100644 docs/examples/rust/restexample/examples/query.rs diff --git a/docs/examples/rust/nativeexample/examples/connect.rs b/docs/examples/rust/nativeexample/examples/connect.rs index dee6db2a41..7da09ae7ec 100644 --- a/docs/examples/rust/nativeexample/examples/connect.rs +++ b/docs/examples/rust/nativeexample/examples/connect.rs @@ -1,9 +1,17 @@ use taos::*; #[tokio::main] -async fn main() -> Result<(), Error> { - #[allow(unused_variables)] - let taos = TaosBuilder::from_dsn("taos://localhost:6030")?.build()?; - println!("Connected to localhost with native connection successfully."); - Ok(()) +async fn main() -> anyhow::Result<()> { + let dsn = "taos://localhost:6030".to_string(); + + match TaosBuilder::from_dsn(&dsn)?.build().await { + Ok(_taos) => { + println!("Connected to {} successfully.", dsn); + Ok(()) + } + Err(err) => { + eprintln!("Failed to connect to {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } } diff --git a/docs/examples/rust/nativeexample/examples/createdb.rs b/docs/examples/rust/nativeexample/examples/createdb.rs new file mode 100644 index 0000000000..d3b2f5178b --- /dev/null +++ b/docs/examples/rust/nativeexample/examples/createdb.rs @@ -0,0 +1,35 @@ +use taos::*; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let url = "taos://localhost:6030"; + + // ANCHOR: create_db_and_table + let taos = TaosBuilder::from_dsn(url)?.build().await?; + + // create database and use it + match taos.exec_many([ + "CREATE DATABASE IF NOT EXISTS power", + ]).await { + Ok(afffected_rows) => println!("Create database power successfully, rowsAffected: {}", afffected_rows), + Err(err) => { + eprintln!("Failed to create database power; ErrMessage: {}", err); + return Err(err.into()); + } + } + + // create super table + match taos.exec_many([ + "CREATE STABLE IF NOT EXISTS power.meters (`ts` TIMESTAMP, `current` FLOAT, `voltage` INT, `phase` FLOAT) \ + TAGS (`groupid` INT, `location` BINARY(24))", + ]).await { + Ok(afffected_rows) => println!("Create stable power.meters successfully, rowsAffected: {}", afffected_rows), + Err(err) => { + eprintln!("Failed to create stable power.meters; ErrMessage: {}", err); + return Err(err.into()); + } + } + + Ok(()) + // ANCHOR_END: create_db_and_table +} diff --git a/docs/examples/rust/nativeexample/examples/insert.rs b/docs/examples/rust/nativeexample/examples/insert.rs new file mode 100644 index 0000000000..d551da436e --- /dev/null +++ b/docs/examples/rust/nativeexample/examples/insert.rs @@ -0,0 +1,31 @@ +use taos::*; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let dsn = "taos://localhost:6030"; + let builder = TaosBuilder::from_dsn(dsn)?; + + let taos = builder.build().await?; + + + // ANCHOR: insert_data + match taos.exec(r#"INSERT INTO + power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') + VALUES + (NOW + 1a, 10.30000, 219, 0.31000) + (NOW + 2a, 12.60000, 218, 0.33000) + (NOW + 3a, 12.30000, 221, 0.31000) + power.d1002 USING power.meters TAGS(3, 'California.SanFrancisco') + VALUES + (NOW + 1a, 10.30000, 218, 0.25000) "#).await{ + Ok(affected_rows) => println!("Successfully inserted {} rows to power.meters.", affected_rows), + Err(err) => { + eprintln!("Failed to insert data to power.meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } + + // ANCHOR_END: insert_data + + Ok(()) +} diff --git a/docs/examples/rust/nativeexample/examples/query.rs b/docs/examples/rust/nativeexample/examples/query.rs index 08ec223761..6b6fde6a31 100644 --- a/docs/examples/rust/nativeexample/examples/query.rs +++ b/docs/examples/rust/nativeexample/examples/query.rs @@ -9,58 +9,33 @@ async fn main() -> anyhow::Result<()> { let taos = builder.build().await?; - // ANCHOR: create_db_and_table - let db = "power"; - // create database - taos.exec_many([ - format!("CREATE DATABASE IF NOT EXISTS `{db}`"), - format!("USE `{db}`"), - ]) - .await?; - println!("Create database power successfully."); - - // create super table - taos.exec_many([ - "CREATE STABLE IF NOT EXISTS `meters` (`ts` TIMESTAMP, `current` FLOAT, `voltage` INT, `phase` FLOAT) \ - TAGS (`groupid` INT, `location` BINARY(24))", - ]).await?; - println!("Create stable meters successfully."); - - // ANCHOR_END: create_db_and_table - - // ANCHOR: insert_data - let inserted = taos.exec(r#"INSERT INTO - power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') - VALUES - (NOW + 1a, 10.30000, 219, 0.31000) - (NOW + 2a, 12.60000, 218, 0.33000) - (NOW + 3a, 12.30000, 221, 0.31000) - power.d1002 USING power.meters TAGS(3, 'California.SanFrancisco') - VALUES - (NOW + 1a, 10.30000, 218, 0.25000) "#).await?; - - println!("inserted: {} rows to power.meters successfully.", inserted); - // ANCHOR_END: insert_data - // ANCHOR: query_data // query data, make sure the database and table are created before - let mut result = taos.query("SELECT ts, current, location FROM power.meters limit 100").await?; - - for field in result.fields() { - println!("got field: {}", field.name()); - } - - let mut rows = result.rows(); - let mut nrows = 0; - while let Some(row) = rows.try_next().await? { - for (col, (name, value)) in row.enumerate() { - println!( - "[{}] got value in col {} (named `{:>8}`): {}", - nrows, col, name, value - ); + match taos.query("SELECT ts, current, location FROM power.meters limit 100").await{ + Ok(mut result) => { + for field in result.fields() { + println!("got field: {}", field.name()); + } + + let mut rows = result.rows(); + let mut nrows = 0; + while let Some(row) = rows.try_next().await? { + for (col, (name, value)) in row.enumerate() { + println!( + "[{}] got value in col {} (named `{:>8}`): {}", + nrows, col, name, value + ); + } + nrows += 1; + } + } + Err(err) => { + eprintln!("Failed to query data from power.meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); } - nrows += 1; } + + // ANCHOR_END: query_data // ANCHOR: query_data_2 @@ -72,30 +47,56 @@ async fn main() -> anyhow::Result<()> { ts: DateTime, // float to f32 current: Option, - // int to i32 - voltage: Option, - phase: Option, - groupid: i32, // binary/varchar to String location: String, } - let records: Vec = taos - .query("select ts, current, voltage, phase, groupid, location from power.meters limit 100") - .await? - .deserialize() - .try_collect() - .await?; - - dbg!(records); + match taos.query("SELECT ts, current, location FROM power.meters limit 100").await { + Ok(mut query) => { + match query.deserialize::().try_collect::>().await { + Ok(records) => { + dbg!(records); + } + Err(err) => { + eprintln!("Failed to deserialize query results; ErrMessage: {}", err); + return Err(err.into()); + } + } + } + Err(err) => { + eprintln!("Failed to query data from power.meters, url: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } // ANCHOR_END: query_data_2 // ANCHOR: query_with_req_id - let result = taos.query_with_req_id("SELECT ts, current, location FROM power.meters limit 1", 1).await?; - for field in result.fields() { - println!("got field: {}", field.name()); + + let req_id :u64 = 3; + match taos.query_with_req_id("SELECT ts, current, location FROM power.meters limit 1", req_id).await{ + Ok(mut result) => { + for field in result.fields() { + println!("got field: {}", field.name()); + } + + let mut rows = result.rows(); + let mut nrows = 0; + while let Some(row) = rows.try_next().await? { + for (col, (name, value)) in row.enumerate() { + println!( + "[{}] got value in col {} (named `{:>8}`): {}", + nrows, col, name, value + ); + } + nrows += 1; + } + } + Err(err) => { + eprintln!("Failed to execute sql with reqId: {}, dsn: {}; ErrMessage: {}", req_id, dsn, err); + return Err(err.into()); + } } - println!("query with reqId successfully"); + // ANCHOR_END: query_with_req_id Ok(()) } diff --git a/docs/examples/rust/nativeexample/examples/schemaless.rs b/docs/examples/rust/nativeexample/examples/schemaless.rs index 9e8eab4597..88e9ef4584 100644 --- a/docs/examples/rust/nativeexample/examples/schemaless.rs +++ b/docs/examples/rust/nativeexample/examples/schemaless.rs @@ -11,7 +11,8 @@ use taos::taos_query; async fn main() -> anyhow::Result<()> { std::env::set_var("RUST_LOG", "taos=debug"); pretty_env_logger::init(); - let dsn = "taos://localhost:6030".to_string(); + let host = "localhost"; + let dsn = format!("taos://{}:6030", host); log::debug!("dsn: {:?}", &dsn); let client = TaosBuilder::from_dsn(dsn)?.build().await?; @@ -39,7 +40,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(100u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } // SchemalessProtocol::Telnet let data = [ @@ -55,7 +62,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(200u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } // SchemalessProtocol::Json let data = [ @@ -80,7 +93,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(300u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } println!("Inserted data with schemaless successfully."); Ok(()) diff --git a/docs/examples/rust/nativeexample/examples/stmt.rs b/docs/examples/rust/nativeexample/examples/stmt.rs index 04faa888bf..de35ae2972 100644 --- a/docs/examples/rust/nativeexample/examples/stmt.rs +++ b/docs/examples/rust/nativeexample/examples/stmt.rs @@ -2,12 +2,13 @@ use taos::*; #[tokio::main] async fn main() -> anyhow::Result<()> { - let taos = TaosBuilder::from_dsn("taos://")?.build().await?; + let dsn = "taos://localhost:6030"; + let taos = TaosBuilder::from_dsn(dsn)?.build().await?; taos.exec("DROP DATABASE IF EXISTS power").await?; taos.create_database("power").await?; taos.use_database("power").await?; - taos.exec("CREATE STABLE IF NOT EXISTS meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)").await?; + taos.exec("CREATE STABLE IF NOT EXISTS power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))").await?; let mut stmt = Stmt::init(&taos).await?; stmt.prepare("INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)").await?; @@ -15,8 +16,8 @@ async fn main() -> anyhow::Result<()> { const NUM_TABLES: usize = 10; const NUM_ROWS: usize = 10; for i in 0..NUM_TABLES { - let table_name = format!("d{}", i); - let tags = vec![Value::VarChar("California.SanFransico".into()), Value::Int(2)]; + let table_name = format!("d_bind_{}", i); + let tags = vec![Value::Int(i as i32), Value::VarChar(format!("location_{}", i).into())]; // set table name and tags for the prepared statement. stmt.set_tbname_tags(&table_name, &tags).await?; @@ -35,9 +36,13 @@ async fn main() -> anyhow::Result<()> { } // execute. - let rows = stmt.execute().await?; - assert_eq!(rows, NUM_TABLES * NUM_ROWS); + match stmt.execute().await{ + Ok(affected_rows) => println!("Successfully inserted {} rows to power.meters.", affected_rows), + Err(err) => { + eprintln!("Failed to insert to table meters using stmt, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } - println!("execute stmt insert successfully"); Ok(()) } diff --git a/docs/examples/rust/nativeexample/examples/tmq.rs b/docs/examples/rust/nativeexample/examples/tmq.rs index 4adfd28989..4ae71bc445 100644 --- a/docs/examples/rust/nativeexample/examples/tmq.rs +++ b/docs/examples/rust/nativeexample/examples/tmq.rs @@ -12,7 +12,7 @@ async fn main() -> anyhow::Result<()> { use taos_query::prelude::*; // ANCHOR: create_consumer_dsn let dsn = "taos://localhost:6030".to_string(); - log::info!("dsn: {}", dsn); + println!("dsn: {}", dsn); let mut dsn = Dsn::from_str(&dsn)?; // ANCHOR_END: create_consumer_dsn @@ -37,20 +37,36 @@ async fn main() -> anyhow::Result<()> { // ANCHOR_END: create_topic // ANCHOR: create_consumer_ac + let group_id = "group1".to_string(); + let client_id = "client1".to_string(); dsn.params.insert("auto.offset.reset".to_string(), "latest".to_string()); dsn.params.insert("msg.with.table.name".to_string(), "true".to_string()); dsn.params.insert("enable.auto.commit".to_string(), "true".to_string()); dsn.params.insert("auto.commit.interval.ms".to_string(), "1000".to_string()); - dsn.params.insert("group.id".to_string(), "group1".to_string()); - dsn.params.insert("client.id".to_string(), "client1".to_string()); + dsn.params.insert("group.id".to_string(), group_id.clone()); + dsn.params.insert("client.id".to_string(), client_id.clone()); let builder = TmqBuilder::from_dsn(&dsn)?; - let mut consumer = builder.build().await?; + let mut consumer = match builder.build().await{ + Ok(consumer) => { + println!("Create consumer successfully, dsn: {}, groupId: {}, clientId: {}.", dsn, group_id, client_id); + consumer + } + Err(err) => { + eprintln!("Failed to create consumer, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + }; // ANCHOR_END: create_consumer_ac - // ANCHOR: subscribe - consumer.subscribe(["topic_meters"]).await?; - // ANCHOR_END: subscribe + // ANCHOR: consume + match consumer.subscribe(["topic_meters"]).await{ + Ok(_) => println!("subscribe topics successfully."), + Err(err) => { + eprintln!("Failed to subscribe topic_meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } #[derive(Debug, serde::Deserialize)] #[allow(dead_code)] @@ -67,8 +83,6 @@ async fn main() -> anyhow::Result<()> { location: String, } - // ANCHOR: consume - consumer .stream() .try_for_each(|(offset, message)| async move { @@ -85,7 +99,10 @@ async fn main() -> anyhow::Result<()> { } Ok(()) }) - .await?; + .await.map_err(|e| { + eprintln!("Failed to execute consumer functions. ErrMessage: {:?}", e); + e + })?; // ANCHOR_END: consume @@ -105,16 +122,25 @@ async fn main() -> anyhow::Result<()> { } } // commit offset manually when you have processed the message. - consumer.commit(offset).await?; + match consumer.commit(offset).await{ + Ok(_) => println!("commit offset manually successfully."), + Err(err) => { + eprintln!("Failed to commit offset manually, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } Ok(()) }) - .await?; + .await.map_err(|e| { + eprintln!("Failed to execute consumer functions. ErrMessage: {:?}", e); + e + })?; // ANCHOR_END: consumer_commit_manually - // ANCHOR: assignments + + // ANCHOR: seek_offset let assignments = consumer.assignments().await.unwrap(); - log::info!("assignments: {:?}", assignments); - // ANCHOR_END: assignments + println!("assignments: {:?}", assignments); // seek offset for topic_vec_assignment in assignments { @@ -125,7 +151,7 @@ async fn main() -> anyhow::Result<()> { let current = assignment.current_offset(); let begin = assignment.begin(); let end = assignment.end(); - log::debug!( + println!( "topic: {}, vgroup_id: {}, current offset: {} begin {}, end: {}", topic, vgroup_id, @@ -133,23 +159,24 @@ async fn main() -> anyhow::Result<()> { begin, end ); - // ANCHOR: seek_offset - let res = consumer.offset_seek(topic, vgroup_id, end).await; - if res.is_err() { - log::error!("seek offset error: {:?}", res); - let a = consumer.assignments().await.unwrap(); - log::error!("assignments: {:?}", a); + + match consumer.offset_seek(topic, vgroup_id, begin).await{ + Ok(_) => (), + Err(err) => { + eprintln!("seek example failed; ErrMessage: {}", err); + return Err(err.into()); + } } - // ANCHOR_END: seek_offset } let topic_assignment = consumer.topic_assignment(topic).await; - log::debug!("topic assignment: {:?}", topic_assignment); + println!("topic assignment: {:?}", topic_assignment); } - + println!("assignment seek to beginning successfully."); // after seek offset let assignments = consumer.assignments().await.unwrap(); - log::info!("after seek offset assignments: {:?}", assignments); + println!("after seek offset assignments: {:?}", assignments); + // ANCHOR_END: seek_offset // ANCHOR: unsubscribe consumer.unsubscribe().await; diff --git a/docs/examples/rust/restexample/examples/connect.rs b/docs/examples/rust/restexample/examples/connect.rs index 0c89517f22..535e265a97 100644 --- a/docs/examples/rust/restexample/examples/connect.rs +++ b/docs/examples/rust/restexample/examples/connect.rs @@ -1,9 +1,17 @@ use taos::*; #[tokio::main] -async fn main() -> Result<(), Error> { - #[allow(unused_variables)] - let taos = TaosBuilder::from_dsn("taos+ws://localhost:6041")?.build()?; - println!("Connected to localhost with websocket connection successfully."); - Ok(()) +async fn main() -> anyhow::Result<()> { + let dsn = "ws://localhost:6041".to_string(); + + match TaosBuilder::from_dsn(&dsn)?.build().await { + Ok(_taos) => { + println!("Connected to {} successfully.", dsn); + Ok(()) + } + Err(err) => { + eprintln!("Failed to connect to {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } } diff --git a/docs/examples/rust/restexample/examples/createdb.rs b/docs/examples/rust/restexample/examples/createdb.rs new file mode 100644 index 0000000000..e061f1d835 --- /dev/null +++ b/docs/examples/rust/restexample/examples/createdb.rs @@ -0,0 +1,35 @@ +use taos::*; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let url = "ws://localhost:6041"; + + // ANCHOR: create_db_and_table + let taos = TaosBuilder::from_dsn(url)?.build().await?; + + // create database and use it + match taos.exec_many([ + "CREATE DATABASE IF NOT EXISTS power", + ]).await { + Ok(afffected_rows) => println!("Create database power successfully, rowsAffected: {}", afffected_rows), + Err(err) => { + eprintln!("Failed to create database power; ErrMessage: {}", err); + return Err(err.into()); + } + } + + // create super table + match taos.exec_many([ + "CREATE STABLE IF NOT EXISTS power.meters (`ts` TIMESTAMP, `current` FLOAT, `voltage` INT, `phase` FLOAT) \ + TAGS (`groupid` INT, `location` BINARY(24))", + ]).await { + Ok(afffected_rows) => println!("Create stable power.meters successfully, rowsAffected: {}", afffected_rows), + Err(err) => { + eprintln!("Failed to create stable power.meters; ErrMessage: {}", err); + return Err(err.into()); + } + } + + Ok(()) + // ANCHOR_END: create_db_and_table +} diff --git a/docs/examples/rust/restexample/examples/insert.rs b/docs/examples/rust/restexample/examples/insert.rs new file mode 100644 index 0000000000..62522575ee --- /dev/null +++ b/docs/examples/rust/restexample/examples/insert.rs @@ -0,0 +1,31 @@ +use taos::*; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let dsn = "ws://localhost:6041"; + let builder = TaosBuilder::from_dsn(dsn)?; + + let taos = builder.build().await?; + + + // ANCHOR: insert_data + match taos.exec(r#"INSERT INTO + power.d1001 USING power.meters TAGS(2,'California.SanFrancisco') + VALUES + (NOW + 1a, 10.30000, 219, 0.31000) + (NOW + 2a, 12.60000, 218, 0.33000) + (NOW + 3a, 12.30000, 221, 0.31000) + power.d1002 USING power.meters TAGS(3, 'California.SanFrancisco') + VALUES + (NOW + 1a, 10.30000, 218, 0.25000) "#).await{ + Ok(affected_rows) => println!("Successfully inserted {} rows to power.meters.", affected_rows), + Err(err) => { + eprintln!("Failed to insert data to power.meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } + + // ANCHOR_END: insert_data + + Ok(()) +} diff --git a/docs/examples/rust/restexample/examples/query.rs b/docs/examples/rust/restexample/examples/query.rs new file mode 100644 index 0000000000..4e69f9fc97 --- /dev/null +++ b/docs/examples/rust/restexample/examples/query.rs @@ -0,0 +1,102 @@ +use taos::*; +use chrono::Local; +use chrono::DateTime; + +#[tokio::main] +async fn main() -> anyhow::Result<()> { + let dsn = "ws://localhost:6041"; + let builder = TaosBuilder::from_dsn(dsn)?; + + let taos = builder.build().await?; + + // ANCHOR: query_data + // query data, make sure the database and table are created before + match taos.query("SELECT ts, current, location FROM power.meters limit 100").await{ + Ok(mut result) => { + for field in result.fields() { + println!("got field: {}", field.name()); + } + + let mut rows = result.rows(); + let mut nrows = 0; + while let Some(row) = rows.try_next().await? { + for (col, (name, value)) in row.enumerate() { + println!( + "[{}] got value in col {} (named `{:>8}`): {}", + nrows, col, name, value + ); + } + nrows += 1; + } + } + Err(err) => { + eprintln!("Failed to query data from power.meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } + + + // ANCHOR_END: query_data + + // ANCHOR: query_data_2 + // query data, make sure the database and table are created before + #[derive(Debug, serde::Deserialize)] + #[allow(dead_code)] + struct Record { + // deserialize timestamp to chrono::DateTime + ts: DateTime, + // float to f32 + current: Option, + // binary/varchar to String + location: String, + } + + match taos.query("SELECT ts, current, location FROM power.meters limit 100").await { + Ok(mut query) => { + match query.deserialize::().try_collect::>().await { + Ok(records) => { + dbg!(records); + } + Err(err) => { + eprintln!("Failed to deserialize query results; ErrMessage: {}", err); + return Err(err.into()); + } + } + } + Err(err) => { + eprintln!("Failed to query data from power.meters, url: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } + // ANCHOR_END: query_data_2 + + // ANCHOR: query_with_req_id + + let req_id :u64 = 3; + match taos.query_with_req_id("SELECT ts, current, location FROM power.meters limit 1", req_id).await{ + Ok(mut result) => { + for field in result.fields() { + println!("got field: {}", field.name()); + } + + let mut rows = result.rows(); + let mut nrows = 0; + while let Some(row) = rows.try_next().await? { + for (col, (name, value)) in row.enumerate() { + println!( + "[{}] got value in col {} (named `{:>8}`): {}", + nrows, col, name, value + ); + } + nrows += 1; + } + } + Err(err) => { + eprintln!("Failed to execute sql with reqId: {}, dsn: {}; ErrMessage: {}", req_id, dsn, err); + return Err(err.into()); + } + } + + // ANCHOR_END: query_with_req_id + Ok(()) +} diff --git a/docs/examples/rust/restexample/examples/schemaless.rs b/docs/examples/rust/restexample/examples/schemaless.rs index a0ee1809e5..f629d66663 100644 --- a/docs/examples/rust/restexample/examples/schemaless.rs +++ b/docs/examples/rust/restexample/examples/schemaless.rs @@ -11,7 +11,8 @@ use taos::taos_query; async fn main() -> anyhow::Result<()> { std::env::set_var("RUST_LOG", "taos=debug"); pretty_env_logger::init(); - let dsn = "http://localhost:6041/power".to_string(); + let host = "localhost"; + let dsn = format!("ws://{}:6041/power", host); log::debug!("dsn: {:?}", &dsn); let client = TaosBuilder::from_dsn(dsn)?.build().await?; @@ -30,7 +31,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(100u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } // SchemalessProtocol::Telnet let data = [ @@ -46,7 +53,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(200u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } // SchemalessProtocol::Json let data = [ @@ -71,7 +84,13 @@ async fn main() -> anyhow::Result<()> { .ttl(1000) .req_id(300u64) .build()?; - assert_eq!(client.put(&sml_data).await?, ()); + match client.put(&sml_data).await{ + Ok(_) => {}, + Err(err) => { + eprintln!("Failed to insert data with schemaless, host: {}; ErrMessage: {}", host, err); + return Err(err.into()); + } + } println!("Inserted data with schemaless successfully."); Ok(()) diff --git a/docs/examples/rust/restexample/examples/stmt.rs b/docs/examples/rust/restexample/examples/stmt.rs index 8148050e15..636b6780cd 100644 --- a/docs/examples/rust/restexample/examples/stmt.rs +++ b/docs/examples/rust/restexample/examples/stmt.rs @@ -2,12 +2,13 @@ use taos::*; #[tokio::main] async fn main() -> anyhow::Result<()> { - let taos = TaosBuilder::from_dsn("ws://")?.build().await?; + let dsn = "ws://"; + let taos = TaosBuilder::from_dsn(dsn)?.build().await?; taos.exec("DROP DATABASE IF EXISTS power").await?; taos.create_database("power").await?; taos.use_database("power").await?; - taos.exec("CREATE STABLE IF NOT EXISTS meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)").await?; + taos.exec("CREATE STABLE IF NOT EXISTS power.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))").await?; let mut stmt = Stmt::init(&taos).await?; stmt.prepare("INSERT INTO ? USING meters TAGS(?, ?) VALUES(?, ?, ?, ?)").await?; @@ -15,8 +16,8 @@ async fn main() -> anyhow::Result<()> { const NUM_TABLES: usize = 10; const NUM_ROWS: usize = 10; for i in 0..NUM_TABLES { - let table_name = format!("d{}", i); - let tags = vec![Value::VarChar("California.SanFransico".into()), Value::Int(2)]; + let table_name = format!("d_bind_{}", i); + let tags = vec![Value::Int(i as i32), Value::VarChar(format!("location_{}", i).into())]; // set table name and tags for the prepared statement. stmt.set_tbname_tags(&table_name, &tags).await?; @@ -35,9 +36,13 @@ async fn main() -> anyhow::Result<()> { } // execute. - let rows = stmt.execute().await?; - assert_eq!(rows, NUM_TABLES * NUM_ROWS); - - println!("execute stmt insert successfully"); + match stmt.execute().await{ + Ok(affected_rows) => println!("Successfully inserted {} rows to power.meters.", affected_rows), + Err(err) => { + eprintln!("Failed to insert to table meters using stmt, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } + Ok(()) } diff --git a/docs/examples/rust/restexample/examples/tmq.rs b/docs/examples/rust/restexample/examples/tmq.rs index 48df89d5bf..046e1ec59c 100644 --- a/docs/examples/rust/restexample/examples/tmq.rs +++ b/docs/examples/rust/restexample/examples/tmq.rs @@ -12,7 +12,7 @@ async fn main() -> anyhow::Result<()> { use taos_query::prelude::*; // ANCHOR: create_consumer_dsn let dsn = "ws://localhost:6041".to_string(); - log::info!("dsn: {}", dsn); + println!("dsn: {}", dsn); let mut dsn = Dsn::from_str(&dsn)?; // ANCHOR_END: create_consumer_dsn @@ -37,20 +37,36 @@ async fn main() -> anyhow::Result<()> { // ANCHOR_END: create_topic // ANCHOR: create_consumer_ac + let group_id = "group1".to_string(); + let client_id = "client1".to_string(); dsn.params.insert("auto.offset.reset".to_string(), "latest".to_string()); dsn.params.insert("msg.with.table.name".to_string(), "true".to_string()); dsn.params.insert("enable.auto.commit".to_string(), "true".to_string()); dsn.params.insert("auto.commit.interval.ms".to_string(), "1000".to_string()); - dsn.params.insert("group.id".to_string(), "group1".to_string()); - dsn.params.insert("client.id".to_string(), "client1".to_string()); + dsn.params.insert("group.id".to_string(), group_id.clone()); + dsn.params.insert("client.id".to_string(), client_id.clone()); let builder = TmqBuilder::from_dsn(&dsn)?; - let mut consumer = builder.build().await?; + let mut consumer = match builder.build().await{ + Ok(consumer) => { + println!("Create consumer successfully, dsn: {}, groupId: {}, clientId: {}.", dsn, group_id, client_id); + consumer + } + Err(err) => { + eprintln!("Failed to create consumer, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + }; // ANCHOR_END: create_consumer_ac - // ANCHOR: subscribe - consumer.subscribe(["topic_meters"]).await?; - // ANCHOR_END: subscribe + // ANCHOR: consume + match consumer.subscribe(["topic_meters"]).await{ + Ok(_) => println!("subscribe topics successfully."), + Err(err) => { + eprintln!("Failed to subscribe topic_meters, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } #[derive(Debug, serde::Deserialize)] #[allow(dead_code)] @@ -67,8 +83,6 @@ async fn main() -> anyhow::Result<()> { location: String, } - // ANCHOR: consume - consumer .stream() .try_for_each(|(offset, message)| async move { @@ -85,7 +99,10 @@ async fn main() -> anyhow::Result<()> { } Ok(()) }) - .await?; + .await.map_err(|e| { + eprintln!("Failed to poll data; ErrMessage: {:?}", e); + e + })?; // ANCHOR_END: consume @@ -105,16 +122,25 @@ async fn main() -> anyhow::Result<()> { } } // commit offset manually when you have processed the message. - consumer.commit(offset).await?; + match consumer.commit(offset).await{ + Ok(_) => println!("commit offset manually successfully."), + Err(err) => { + eprintln!("Failed to commit offset manually, dsn: {}; ErrMessage: {}", dsn, err); + return Err(err.into()); + } + } Ok(()) }) - .await?; + .await.map_err(|e| { + eprintln!("Failed to execute consumer functions. ErrMessage: {:?}", e); + e + })?; // ANCHOR_END: consumer_commit_manually - // ANCHOR: assignments + + // ANCHOR: seek_offset let assignments = consumer.assignments().await.unwrap(); - log::info!("assignments: {:?}", assignments); - // ANCHOR_END: assignments + println!("assignments: {:?}", assignments); // seek offset for topic_vec_assignment in assignments { @@ -125,7 +151,7 @@ async fn main() -> anyhow::Result<()> { let current = assignment.current_offset(); let begin = assignment.begin(); let end = assignment.end(); - log::debug!( + println!( "topic: {}, vgroup_id: {}, current offset: {} begin {}, end: {}", topic, vgroup_id, @@ -133,23 +159,24 @@ async fn main() -> anyhow::Result<()> { begin, end ); - // ANCHOR: seek_offset - let res = consumer.offset_seek(topic, vgroup_id, end).await; - if res.is_err() { - log::error!("seek offset error: {:?}", res); - let a = consumer.assignments().await.unwrap(); - log::error!("assignments: {:?}", a); + + match consumer.offset_seek(topic, vgroup_id, begin).await{ + Ok(_) => (), + Err(err) => { + eprintln!("seek example failed; ErrMessage: {}", err); + return Err(err.into()); + } } - // ANCHOR_END: seek_offset } let topic_assignment = consumer.topic_assignment(topic).await; - log::debug!("topic assignment: {:?}", topic_assignment); + println!("topic assignment: {:?}", topic_assignment); } - + println!("assignment seek to beginning successfully."); // after seek offset let assignments = consumer.assignments().await.unwrap(); - log::info!("after seek offset assignments: {:?}", assignments); + println!("after seek offset assignments: {:?}", assignments); + // ANCHOR_END: seek_offset // ANCHOR: unsubscribe consumer.unsubscribe().await; diff --git a/docs/zh/08-develop/02-sql.md b/docs/zh/08-develop/02-sql.md index 1651bf21cd..7e42e38949 100644 --- a/docs/zh/08-develop/02-sql.md +++ b/docs/zh/08-develop/02-sql.md @@ -53,7 +53,7 @@ REST API：直接调用 `taosadapter` 提供的 REST API 接口，进行数据 ```rust -{{#include docs/examples/rust/nativeexample/examples/query.rs:create_db_and_table}} +{{#include docs/examples/rust/nativeexample/examples/createdb.rs:create_db_and_table}} ``` @@ -129,7 +129,7 @@ NOW 为系统内部函数，默认为客户端所在计算机当前时间。 NOW ```rust -{{#include docs/examples/rust/nativeexample/examples/query.rs:insert_data}} +{{#include docs/examples/rust/nativeexample/examples/insert.rs:insert_data}} ``` diff --git a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java index f2fa345f47..64042ed309 100644 --- a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java +++ b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java @@ -42,10 +42,10 @@ public class ConsumerLoopFull { return consumer; } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info - System.out.println("Failed to create websocket consumer, host : " + config.getProperty("bootstrap.servers") + "; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); + System.out.println("Failed to create native consumer, host : " + config.getProperty("bootstrap.servers") + "; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to create consumer", ex); } catch (Exception ex) { - System.out.println("Failed to create websocket consumer, host : " + config.getProperty("bootstrap.servers") + System.out.println("Failed to create native consumer, host : " + config.getProperty("bootstrap.servers") + "; ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to create consumer", ex); } @@ -59,7 +59,7 @@ public class ConsumerLoopFull { // subscribe to the topics consumer.subscribe(topics); - System.out.println("subscribe topics successfully"); + System.out.println("subscribe topics successfully."); for (int i = 0; i < 50; i++) { // poll data ConsumerRecords records = consumer.poll(Duration.ofMillis(100)); @@ -88,7 +88,7 @@ public class ConsumerLoopFull { // subscribe to the topics consumer.subscribe(topics); - System.out.println("subscribe topics successfully"); + System.out.println("subscribe topics successfully."); Set assignment = consumer.assignment(); System.out.println("now assignment: " + JSON.toJSONString(assignment)); @@ -99,7 +99,7 @@ public class ConsumerLoopFull { } consumer.seekToBeginning(assignment); - System.out.println("assignment seek to beginning successfully"); + System.out.println("assignment seek to beginning successfully."); } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info System.out.println("seek example failed; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); @@ -317,22 +317,22 @@ public class ConsumerLoopFull { System.out.println("Failed to prepare data, ErrMessage: " + ex.getMessage()); return; } - System.out.println("pollDataExample executed successfully"); + System.out.println("pollDataExample executed successfully."); }); try { TaosConsumer consumer = getConsumer(); pollExample(consumer); - System.out.println("pollExample executed successfully"); + System.out.println("pollExample executed successfully."); consumer.unsubscribe(); seekExample(consumer); - System.out.println("seekExample executed successfully"); + System.out.println("seekExample executed successfully."); consumer.unsubscribe(); commitExample(consumer); - System.out.println("commitExample executed successfully"); + System.out.println("commitExample executed successfully."); consumer.unsubscribe(); unsubscribeExample(consumer); diff --git a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java index 3ac51f61fc..78f743b55d 100644 --- a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java +++ b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java @@ -57,7 +57,7 @@ public class WsConsumerLoopFull { // subscribe to the topics consumer.subscribe(topics); - System.out.println("subscribe topics successfully"); + System.out.println("subscribe topics successfully."); for (int i = 0; i < 50; i++) { // poll data ConsumerRecords records = consumer.poll(Duration.ofMillis(100)); @@ -86,7 +86,7 @@ public class WsConsumerLoopFull { // subscribe to the topics consumer.subscribe(topics); - System.out.println("subscribe topics successfully"); + System.out.println("subscribe topics successfully."); Set assignment = consumer.assignment(); System.out.println("now assignment: " + JSON.toJSONString(assignment)); @@ -97,7 +97,7 @@ public class WsConsumerLoopFull { } consumer.seekToBeginning(assignment); - System.out.println("assignment seek to beginning successfully"); + System.out.println("assignment seek to beginning successfully."); } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info System.out.println("seek example failed; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); @@ -315,26 +315,26 @@ public class WsConsumerLoopFull { System.out.println("Failed to prepare data, ErrMessage: " + ex.getMessage()); return; } - System.out.println("pollDataExample executed successfully"); + System.out.println("pollDataExample executed successfully."); }); try { TaosConsumer consumer = getConsumer(); pollExample(consumer); - System.out.println("pollExample executed successfully"); + System.out.println("pollExample executed successfully."); consumer.unsubscribe(); seekExample(consumer); - System.out.println("seekExample executed successfully"); + System.out.println("seekExample executed successfully."); consumer.unsubscribe(); commitExample(consumer); - System.out.println("commitExample executed successfully"); + System.out.println("commitExample executed successfully."); consumer.unsubscribe(); unsubscribeExample(consumer); - System.out.println("unsubscribeExample executed successfully"); + System.out.println("unsubscribeExample executed successfully."); } catch (SQLException ex) { System.out.println("Failed to poll data from topic_meters, ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); From d72e0307f0e669a09216ab93fa98e0bbe188458c Mon Sep 17 00:00:00 2001 From: sheyanjie-qq <249478495@qq.com> Date: Mon, 12 Aug 2024 17:44:23 +0800 Subject: [PATCH 2/3] mod rust log --- docs/examples/rust/restexample/examples/tmq.rs | 1 + .../main/java/com/taosdata/example/ConsumerLoopFull.java | 6 +++--- .../main/java/com/taosdata/example/WsConsumerLoopFull.java | 6 +++--- 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/docs/examples/rust/restexample/examples/tmq.rs b/docs/examples/rust/restexample/examples/tmq.rs index 046e1ec59c..c828bd91ac 100644 --- a/docs/examples/rust/restexample/examples/tmq.rs +++ b/docs/examples/rust/restexample/examples/tmq.rs @@ -180,6 +180,7 @@ async fn main() -> anyhow::Result<()> { // ANCHOR: unsubscribe consumer.unsubscribe().await; + println!("consumer unsubscribed successfully."); // ANCHOR_END: unsubscribe tokio::time::sleep(Duration::from_secs(1)).await; diff --git a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java index 64042ed309..39782e787c 100644 --- a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java +++ b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ConsumerLoopFull.java @@ -72,10 +72,10 @@ public class ConsumerLoopFull { } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info - System.out.println("Failed to poll data; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); + System.out.println("Failed to poll data, ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to poll data", ex); } catch (Exception ex) { - System.out.println("Failed to poll data; ErrMessage: " + ex.getMessage()); + System.out.println("Failed to poll data, ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to poll data", ex); } // ANCHOR_END: poll_data_code_piece @@ -149,7 +149,7 @@ public class ConsumerLoopFull { try { // unsubscribe the consumer consumer.unsubscribe(); - System.out.println("unsubscribe consumer successfully."); + System.out.println("consumer unsubscribed successfully."); } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info System.out.println("Failed to unsubscribe consumer. ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); diff --git a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java index 78f743b55d..45767f8461 100644 --- a/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java +++ b/examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/WsConsumerLoopFull.java @@ -70,10 +70,10 @@ public class WsConsumerLoopFull { } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info - System.out.println("Failed to poll data; ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); + System.out.println("Failed to poll data, ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to poll data", ex); } catch (Exception ex) { - System.out.println("Failed to poll data; ErrMessage: " + ex.getMessage()); + System.out.println("Failed to poll data, ErrMessage: " + ex.getMessage()); throw new SQLException("Failed to poll data", ex); } // ANCHOR_END: poll_data_code_piece @@ -147,7 +147,7 @@ public class WsConsumerLoopFull { try { // unsubscribe the consumer consumer.unsubscribe(); - System.out.println("unsubscribe consumer successfully."); + System.out.println("consumer unsubscribed successfully."); } catch (SQLException ex) { // handle any errors, please refer to the JDBC specifications for detailed exceptions info System.out.println("Failed to unsubscribe consumer. ErrCode:" + ex.getErrorCode() + "; ErrMessage: " + ex.getMessage()); From 96379b8c04b83af4174da34a122631476ca73c6a Mon Sep 17 00:00:00 2001 From: t_max <1172915550@qq.com> Date: Mon, 12 Aug 2024 18:21:19 +0800 Subject: [PATCH 3/3] docs: update go example --- docs/examples/go/sqlquery/main.go | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/docs/examples/go/sqlquery/main.go b/docs/examples/go/sqlquery/main.go index e03c2a14c4..1301c79325 100644 --- a/docs/examples/go/sqlquery/main.go +++ b/docs/examples/go/sqlquery/main.go @@ -35,7 +35,7 @@ func main() { } rowsAffected, err = res.RowsAffected() if err != nil { - log.Fatalln("Failed to get create create rowsAffected, url:" + taosDSN + "; ErrMessage: " + err.Error()) + log.Fatalln("Failed to get create db rowsAffected, url:" + taosDSN + "; ErrMessage: " + err.Error()) } // you can check rowsAffected here fmt.Println("Create stable power.meters successfully, rowsAffected:", rowsAffected) @@ -66,7 +66,7 @@ func main() { // query data, make sure the database and table are created before rows, err := db.Query("SELECT ts, current, location FROM power.meters limit 100") if err != nil { - log.Fatal("query data failed:", err) + log.Fatal("Failed to query data from power.meters, url:" + taosDSN + "; ErrMessage: " + err.Error()) } for rows.Next() { var ( @@ -76,7 +76,7 @@ func main() { ) err = rows.Scan(&ts, ¤t, &location) if err != nil { - log.Fatal("scan data failed:", err) + log.Fatal("Failed to scan data, url:" + taosDSN + "; ErrMessage: " + err.Error()) } // you can check data here fmt.Printf("ts: %s, current: %f, location: %s\n", ts, current, location)