Databricks SQL Driver for Go

The Databricks SQL Driver for Go is a Go library that allows you to use Go code to run SQL commands on Databricks compute resources. This article supplements the Databricks SQL Driver for Go README, API reference, and examples.

Requirements

A development machine running Go, version 1.20 or above. To print the installed version of Go, run the command go version. Download and install Go.
An existing cluster or SQL warehouse.
The Server Hostname, Port, and HTTP Path values for the existing cluster or SQL warehouse.
- Get these values for a cluster.
- Get these values for a SQL warehouse.

Getting started with the Databricks SQL Driver for Go

On your development machine with Go 1.20 or above already installed and an existing Go code project already created, create a go.mod file to track your Go code’s dependencies by running the go mod init command, for example:
```
go mod init sample
```
Take a dependency on the Databricks SQL Driver for Go package by running the go mod edit -require command, replacing v1.5.2 with the latest version of the Databricks SQL Driver for Go package as listed in the Releases:
```
go mod edit -require github.com/databricks/databricks-sql-go@v1.5.2
```
Your go.mod file should now look like this:
```
module sample

go 1.20

require github.com/databricks/databricks-sql-go v1.5.2
```

In your project, create a Go code file that imports the Databricks SQL Driver for Go. The following example, in a file named main.go with the following contents, lists all the clusters in your Databricks workspace:

package main

import (
  "database/sql"
  "os"
  _ "github.com/databricks/databricks-sql-go"
)

func main() {
  dsn := os.Getenv("DATABRICKS_DSN")

  if dsn == "" {
    panic("No connection string found. " +
     "Set the DATABRICKS_DSN environment variable, and try again.")
  }

  db, err := sql.Open("databricks", dsn)
  if err != nil {
    panic(err)
  }
  defer db.Close()

  if err := db.Ping(); err != nil {
    panic(err)
  }
}

Add any missing module dependencies by running the go mod tidy command:
```
go mod tidy
```
Note

If you get the error go: warning: "all" matched no packages, you forgot to add a Go code file that imports the Databricks SQL Driver for Go.
Make copies of all packages needed to support builds and tests of packages in your main module, by running the go mod vendor command:
```
go mod vendor
```
Modify your code as needed to set the DATABRICKS_DSN environment variable for Databricks authentication. See also Connect with a DSN connection string.
Run your Go code file, assuming a file named main.go, by running the go run command:
```
go run main.go
```
If no errors are returned, you have successfully authenticated the Databricks SQL Driver for Go with your Databricks workspace and connected to your running Databricks cluster or SQL warehouse in that workspace.

Connect with a DSN connection string

To access clusters and SQL warehouses, use sql.Open() to create a database handle through a data source name (DSN) connection string. This code example retrieves the DSN connection string from an environment variable named DATABRICKS_DSN:

package main

import (
  "database/sql"
  "os"
  _ "github.com/databricks/databricks-sql-go"
)

func main() {
  dsn := os.Getenv("DATABRICKS_DSN")

  if dsn == "" {
    panic("No connection string found. " +
          "Set the DATABRICKS_DSN environment variable, and try again.")
  }

  db, err := sql.Open("databricks", dsn)
  if err != nil {
    panic(err)
  }
  defer db.Close()

  if err := db.Ping(); err != nil {
    panic(err)
  }
}

To specify the DSN connection string in the correct format, see the DSN connection string examples in Authentication. For example, for Databricks personal access token authentication, use the following syntax, where:

<personal-access-token> is your Databricks personal access token from the requirements.
<server-hostname> is the Server Hostname value from the requirements.
<port-number> is the Port value from the requirements, which is typically 443.
<http-path> is the HTTP Path value from the requirements.
<paramX=valueX> is one or more Optional parameters listed later in this article.

token:<personal-access-token>@<server-hostname>:<port-number>/<http-path>?<param1=value1>&<param2=value2>

For example, for a cluster:

token:dapi12345678901234567890123456789012@1234567890123456.7.gcp.databricks.com:443/sql/protocolv1/o/1234567890123456/1234-567890-abcdefgh

For example, for a SQL warehouse:

token:dapi12345678901234567890123456789012@1234567890123456.7.gcp.databricks.com:443/sql/1.0/endpoints/a1b234c5678901d2

Note

As a security best practice, you should not hard-code this DSN connection string into your Go code. Instead, you should retrieve this DSN connection string from a secure location. For example, the code example earlier in this article used an environment variable.

Optional parameters

Supported optional connection parameters can be specified in <param=value>. Some of the more frequently used ones include:
- catalog: Sets the initial catalog name in the session.
- schema: Sets the initial schema name in the session.
- maxRows: Sets up the maximum number of rows fetched per request. The default is 10000.
- timeout: Adds the timeout (in seconds) for the server query execution. The default is no timeout.
- userAgentEntry: Used to identify partners. For more information, see your partner’s documentation.
Supported optional session parameters can be specified in param=value. Some of the more frequently used ones include:
- ansi_mode: A Boolean string. true for session statements to adhere to rules specified by the ANSI SQL specification. The system default is false.
- timezone: A string, for example America/Los_Angeles. Sets the timezone of the session. The system default is UTC.

For example, for a SQL warehouse:

token:dapi12345678901234567890123456789012@1234567890123456.7.gcp.databricks.com:443/sql/1.0/endpoints/a1b234c5678901d2?catalog=hive_metastore&schema=example&maxRows=100&timeout=60&timezone=America/Sao_Paulo&ansi_mode=true

Connect with the `NewConnector` function

Alternatively, use sql.OpenDB() to create a database handle through a new connector object that is created with dbsql.NewConnector() (connecting to Databricks clusters and SQL warehouses with a new connector object requires v1.0.0 or higher of the Databricks SQL Driver for Go). For example:

package main

import (
  "database/sql"
  "os"
  dbsql "github.com/databricks/databricks-sql-go"
)

func main() {
  connector, err := dbsql.NewConnector(
    dbsql.WithAccessToken(os.Getenv("DATABRICKS_ACCESS_TOKEN")),
    dbsql.WithServerHostname(os.Getenv("DATABRICKS_HOST")),
    dbsql.WithPort(443),
    dbsql.WithHTTPPath(os.Getenv("DATABRICKS_HTTP_PATH")),
  )
  if err != nil {
    panic(err)
  }

  db := sql.OpenDB(connector)
  defer db.Close()

  if err := db.Ping(); err != nil {
    panic(err)
  }
}

To specify the correct set of NewConnector settings, see the examples in Authentication.

Note

As a security best practice, you should not hard-code your NewConnector settings into your Go code. Instead, you should retrieve these values from a secure location. For example, the preceding code uses environment variables.

Some of the more frequently used functional options include:

WithAccessToken(<access-token>): Your Databricks personal access token from the requirements. Required string.
WithServerHostname(<server-hostname>): The Server Hostname value from the requirements. Required string.
WithPort(<port>): The server’s port number, typically 443. Required int.
WithHTTPPath(<http-path>): The HTTP Path value from the requirements. Required string.
WithInitialNamespace(<catalog>, <schema>):The catalog and schema name in the session. Optional string, string.
WithMaxRows(<max-rows>): The maximum number of rows fetched per request. The default is 10000. Optional int.
WithSessionParams(<params-map>): The session parameters including “timezone” and “ansi_mode”. Optional map[string]string.
WithTimeout(<timeout>). The timeout (in time.Duration) for the server query execution. The default is no timeout. Optional.
WithUserAgentEntry(<isv-name-plus-product-name>). Used to identify partners. For more information, see your partner’s documentation. Optional string.

For example:

connector, err := dbsql.NewConnector(
  dbsql.WithAccessToken(os.Getenv("DATABRICKS_ACCESS_TOKEN")),
  dbsql.WithServerHostname(os.Getenv("DATABRICKS_HOST")),
  dbsql.WithPort(443),
  dbsql.WithHTTPPath(os.Getenv("DATABRICKS_HTTP_PATH")),
  dbsql.WithInitialNamespace("samples", "nyctaxi"),
  dbsql.WithMaxRows(100),
  dbsql.SessionParams(map[string]string{"timezone": "America/Sao_Paulo", "ansi_mode": "true"}),
  dbsql.WithTimeout(time.Minute),
  dbsql.WithUserAgentEntry("example-user"),
)

Authentication

The Databricks SQL Driver for Go supports Databricks personal access token authentication.

The Databricks SQL Driver for Go does not yet support the following Databricks authentication types:

To use the Databricks SQL Driver for Go with Databricks personal access token authentication, you must first create a Databricks personal access token, as follows:

In your Databricks workspace, click your Databricks username in the top bar, and then select Settings from the drop down.
Click Developer.
Next to Access tokens, click Manage.
Click Generate new token.
(Optional) Enter a comment that helps you to identify this token in the future, and change the token’s default lifetime of 90 days. To create a token with no lifetime (not recommended), leave the Lifetime (days) box empty (blank).
Click Generate.
Copy the displayed token to a secure location, and then click Done.

Note

Be sure to save the copied token in a secure location. Do not share your copied token with others. If you lose the copied token, you cannot regenerate that exact same token. Instead, you must repeat this procedure to create a new token. If you lose the copied token, or you believe that the token has been compromised, Databricks strongly recommends that you immediately delete that token from your workspace by clicking the trash can (Revoke) icon next to the token on the Access tokens page.

If you are not able to create or use tokens in your workspace, this might be because your workspace administrator has disabled tokens or has not given you permission to create or use tokens. See your workspace administrator or the following:

To authenticate the Databricks SQL Driver for Go with a DSN connection string and the code example in Connect with a DSN connection string, use the following DSN connection string syntax, where:

<personal-access-token> is your Databricks personal access token from the requirements.
<server-hostname> is the Server Hostname value from the requirements.
<port-number> is the Port value from the requirements, which is typically 443.
<http-path> is the HTTP Path value from the requirements.

You can also append one or more Optional parameters listed previously in this article.

token:<personal-access-token>@<server-hostname>:<port-number>/<http-path>

To authenticate the Databricks SQL Driver for Go with the NewConnector function, use the following code snippet and the code example in Connect with the NewConnector function, which assumes that you have set the following environment variables:

DATABRICKS_SERVER_HOSTNAMEset to the Server Hostname value for your cluster or SQL warehouse.
DATABRICKS_HTTP_PATH, set to HTTP Path value for your cluster or SQL warehouse.
DATABRICKS_TOKEN, set to the Databricks personal access token.

To set environment variables, see your operating system’s documentation.

connector, err := dbsql.NewConnector(
  dbsql.WithServerHostname(os.Getenv("DATABRICKS_SERVER_HOSTNAME")),
  dbsql.WithHTTPPath(os.Getenv("DATABRICKS_HTTP_PATH")),
  dbsql.WithPort(443),
  dbsql.WithAccessToken(os.Getenv("DATABRICKS_TOKEN")),
)

Query data

The following code example demonstrates how to call the Databricks SQL Driver for Go to run a basic SQL query on a Databricks compute resource. This command returns the first two rows from the trips table in the samples catalog’s nyctaxi schema.

This code example retrieves the DSN connection string from an environment variable named DATABRICKS_DSN.

package main

import (
  "database/sql"
  "fmt"
  "os"
  "time"

  _ "github.com/databricks/databricks-sql-go"
)

func main() {
  dsn := os.Getenv("DATABRICKS_DSN")

  if dsn == "" {
    panic("No connection string found." +
          "Set the DATABRICKS_DSN environment variable, and try again.")
  }

  db, err := sql.Open("databricks", dsn)
  if err != nil {
    panic(err)
  }

  defer db.Close()

  var (
    tpep_pickup_datetime  time.Time
    tpep_dropoff_datetime time.Time
    trip_distance         float64
    fare_amount           float64
    pickup_zip            int
    dropoff_zip           int
  )

  rows, err := db.Query("SELECT * FROM samples.nyctaxi.trips LIMIT 2")
  if err != nil {
    panic(err)
  }

  defer rows.Close()

  fmt.Print("tpep_pickup_datetime,",
    "tpep_dropoff_datetime,",
    "trip_distance,",
    "fare_amount,",
    "pickup_zip,",
    "dropoff_zip\n")

  for rows.Next() {
    err := rows.Scan(&tpep_pickup_datetime,
      &tpep_dropoff_datetime,
      &trip_distance,
      &fare_amount,
      &pickup_zip,
      &dropoff_zip)
    if err != nil {
      panic(err)
    }

    fmt.Print(tpep_pickup_datetime, ",",
      tpep_dropoff_datetime, ",",
      trip_distance, ",",
      fare_amount, ",",
      pickup_zip, ",",
      dropoff_zip, "\n")
  }

  err = rows.Err()
  if err != nil {
    panic(err)
  }
}

Output:

tpep_pickup_datetime,tpep_dropoff_datetime,trip_distance,fare_amount,pickup_zip,dropoff_zip
2016-02-14 16:52:13 +0000 UTC,2016-02-14 17:16:04 +0000 UTC,4.94,19,10282,10171
2016-02-04 18:44:19 +0000 UTC,2016-02-04 18:46:00 +0000 UTC,0.28,3.5,10110,10110

For additional examples, see the examples folder in the databricks/databricks-sql-go repository on GitHub.

Logging

Use github.com/databricks/databricks-sql-go/logger to log messages that the Databricks SQL Driver for Go emits. The following code example uses sql.Open() to create a database handle through a DSN connection string. This code example retrieves the DSN connection string from an environment variable named DATABRICKS_DSN. All log messages that are emitted at the debug level and below are written to the results.log file.

package main

import (
  "database/sql"
  "io"
  "log"
  "os"

  _ "github.com/databricks/databricks-sql-go"
  dbsqllog "github.com/databricks/databricks-sql-go/logger"
)

func main() {
  dsn := os.Getenv("DATABRICKS_DSN")

  // Use the specified file for logging messages to.
  file, err := os.Create("results.log")
  if err != nil {
    log.Fatal(err)
  }
  defer file.Close()

  writer := io.Writer(file)

  // Log messages at the debug level and below.
  if err := dbsqllog.SetLogLevel("debug"); err != nil {
    log.Fatal(err)
  }

  // Log messages to the file.
  dbsqllog.SetLogOutput(writer)

  if dsn == "" {
    panic("Error: Cannot connect. No connection string found. " +
      "Set the DATABRICKS_DSN environment variable, and try again.")
  }

  db, err := sql.Open("databricks", dsn)
  if err != nil {
    panic(err)
  }
  defer db.Close()

  if err := db.Ping(); err != nil {
    panic(err)
  }
}

Additional resources

The Databricks SQL Driver for Go repository on GitHub
The database/sql package home page
The Databricks SQL Driver for Go examples on GitHub