# Go Client for TD-API

This guide covers how to use the Go programming language module for the td-client API.

## Prerequisites

- Basic knowledge of Treasure Data, including [access the the API
key](https://docs.treasuredata.com/display/PD/About+Access+Control).
- A table with data.


## Installation

Install the td-client via the go command line.


```shell
go get github.com/treasure-data/td-client-go
```

## Setup

Initialize a client object using your TD API key. Best practice is to pull the API key from an environment variable.


```go
import (
    td_client "github.com/treasure-data/td-client-go"
    "time"
)

func main() {
    apiKey := os.Getenv("TD_CLIENT_API_KEY")
    client, err := td_client.NewTDClient(td_client.Settings{
        ApiKey: apiKey,
    })
    if err != nil {
        fmt.Println(err.Error())
        return
    }
// code to be continued in the rest of this article
```

## Basic Use

### List Databases and Tables

The code below demonstrates how to list databases and tables from your Treasure Data account.


```go
databases, err := client.ListDatabases()
if err != nil {
    fmt.Println(err.Error())
    return
}
fmt.Printf("%d databases\n", len(*databases))
for _, database := range *databases {
    fmt.Printf("  name: %s\n", database.Name)
    tables, err := client.ListTables(database.Name)
    if err != nil {
        fmt.Println(err.Error())
        return
    }
    fmt.Printf("  %d tables\n", len(*tables))
    for _, table := range *tables {
        fmt.Printf("    name: %s\n", table.Name)
        fmt.Printf("    type: %s\n", table.Type)
        fmt.Printf("    count: %d\n", table.Count)
        fmt.Printf("    primaryKey: %s\n", table.PrimaryKey)
        fmt.Printf("    schema: %v\n", table.Schema)
    }
}
```

### Issue Queries

The example below issues a query from a Go program. The query API is asynchronous--you can check for query completion by polling the job periodically (e.g. by checking the response for `JobStatus(jobID)` calls).


```go
jobId, err := client.SubmitQuery("sample_db2", td_client.Query{
    Type:       "hive", // can also use "trino(presto)"
    Query:      "SELECT COUNT(*) AS c FROM test WHERE a >= 5000",
    ResultUrl:  "", // can use the Result Output feature
    Priority:   0,
    RetryLimit: 0,
})
if err != nil {
    fmt.Println(err.Error())
    return
}
for {
    time.Sleep(1000000000)
    status, err := client.JobStatus(jobId)
    if err != nil {
        fmt.Println(err.Error())
        return
    }
    fmt.Printf("jobStatus:%s\n", status)
    if status != "queued" && status != "running" {
        break
    }
}
```

### Get the Status of Jobs

The example below gets the status of a job by `jobId`.


```go
// get job result
jobDesc, err := client.ShowJob(jobId)
if err != nil {
    fmt.Println(err.Error())
    return
}
fmt.Printf("query:%s\n", jobDesc.Query)
fmt.Printf("debug.cmdOut:%s\n", jobDesc.Debug.CmdOut)
fmt.Printf("debug.stdErr:%s\n", jobDesc.Debug.StdErr)
fmt.Printf("url:%s\n", jobDesc.Url)
fmt.Printf("startAt:%s\n", jobDesc.StartAt.String())
fmt.Printf("endAt:%s\n", jobDesc.EndAt.String())
fmt.Printf("cpuTime:%g\n", jobDesc.CpuTime)
fmt.Printf("resultSize:%d\n", jobDesc.ResultSize)
fmt.Printf("priority:%d\n", jobDesc.Priority)
fmt.Printf("hiveResultSchema:%v\n", jobDesc.HiveResultSchema)
```

## Further Reading

- Source code on [GitHub](https://github.com/treasure-data/td-client-go).
- The [Hive Query Engine](https://docs.treasuredata.com/display/public/PD/About+Hive+Query+Engine)