A Presto client for the Go programming language.
- Native Go implementation
- Connections over HTTP or HTTPS
- HTTP Basic and Kerberos authentication
- Per-query user information for access control
- Support custom HTTP client (tunable conn pools, timeouts, TLS)
- Supports conversion from Presto to native Go data types
string
,sql.NullString
int64
,presto.NullInt64
float64
,presto.NullFloat64
map
,presto.NullMap
time.Time
,presto.NullTime
- Up to 3-dimensional arrays to Go slices, of any supported type
- Go 1.18 or newer
- Presto 0.16x or newer
You need a working environment with Go installed and $GOPATH set.
Download and install presto database/sql driver:
go get github.com/prestodb/presto-go-client/presto
Make sure you have Git installed and in your $PATH.
This Presto client is an implementation of Go's database/sql/driver
interface. In order to use it, you need to import the package and use the database/sql
API then.
Only read operations are supported, such as SHOW and SELECT.
Use presto
as driverName
and a valid DSN as the dataSourceName
.
Example:
import "database/sql"
import _ "github.com/prestodb/presto-go-client/presto"
dsn := "http://user@localhost:8080?catalog=default&schema=test"
db, err := sql.Open("presto", dsn)
HTTP Basic, Kerberos, and JWT authentication are supported.
If the DSN contains a password, the client enables HTTP Basic authentication by setting the Authorization
header in every request to presto.
HTTP Basic authentication is only supported on encrypted connections over HTTPS.
This driver supports Kerberos authentication by setting up the Kerberos fields in the Config struct.
Please refer to the Coordinator Kerberos Authentication for server-side configuration.
This driver supports JWT authentication by setting the AccessToken
field in the configuration. Add the query parameter with the JWT bearer token to be used for authentication. This token will then be sent as a bearer token for all HTTP requests.
This authentication method has lower precedence than HTTP basic authentication.
It's possible to pass user information to presto, different from the principal used to authenticate to the coordinator. See the System Access Control documentation for details.
In order to pass user information in queries to presto, you have to add a NamedArg to the query parameters where the key is X-Presto-User. This parameter is used by the driver to inform presto about the user executing the query regardless of the authentication method for the actual connection, and its value is NOT passed to the query.
Example:
db.Query("SELECT * FROM foobar WHERE id=?", 1, sql.Named("X-Presto-User", string("Alice")))
The position of the X-Presto-User NamedArg is irrelevant and does not affect the query in any way.
The Data Source Name is a URL with a mandatory username, and optional query string parameters that are supported by this driver, in the following format:
http[s]://user[:pass]@host[:port][?parameters]
The easiest way to build your DSN is by using the Config.FormatDSN helper function.
The driver supports both HTTP and HTTPS. If you use HTTPS it's recommended that you also provide a custom http.Client
that can validate (or skip) the security checks of the server certificate, and/or to configure TLS client authentication.
Parameters are case-sensitive
Refer to the Presto Concepts documentation for more information.
Type: string
Valid values: string describing the source of the connection to presto
Default: empty
The source
parameter is optional, but if used, can help presto admins troubleshoot queries and trace them back to the original client.
Type: string
Valid values: the name of a catalog configured in the presto server
Default: empty
The catalog
parameter defines the presto catalog where schemas exist to organize tables.
Type: string
Valid values: the name of an existing schema in the catalog
Default: empty
The schema
parameter defines the presto schema where tables exist. This is also known as namespace in some environments.
Type: string
Valid values: comma-separated list of key=value session properties
Default: empty
The session_properties
parameter must contain valid parameters accepted by the presto server. Run SHOW SESSION
in presto to get the current list.
Type: string
Valid values: the name of a client previously registered to the driver
Default: empty (defaults to http.DefaultClient)
The custom_client
parameter allows the use of custom http.Client
for the communication with presto.
Register your custom client in the driver, then refer to it by name in the DSN, on the call to sql.Open
:
foobarClient := &http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
DualStack: true,
}).DialContext,
MaxIdleConns: 100,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
TLSClientConfig: &tls.Config{
// your config here...
},
},
}
presto.RegisterCustomClient("foobar", foobarClient)
db, err := sql.Open("presto", "https://user@localhost:8080?custom_client=foobar")
http://user@localhost:8080?source=hello&catalog=default&schema=foobar
https://user@localhost:8443?session_properties=query_max_run_time=10m,query_priority=2
As described in the LICENSE file.