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https://github.com/prestodb/presto-go-client

A Presto client for the Go programming language.
https://github.com/prestodb/presto-go-client

big-data golang presto prestodb sql

Last synced: 2 days ago
JSON representation

A Presto client for the Go programming language.

Host: GitHub
URL: https://github.com/prestodb/presto-go-client
Owner: prestodb
License: apache-2.0
Created: 2017-09-08T01:43:37.000Z (about 7 years ago)
Default Branch: master
Last Pushed: 2024-04-26T18:28:41.000Z (7 months ago)
Last Synced: 2024-06-18T12:43:39.086Z (5 months ago)
Topics: big-data, golang, presto, prestodb, sql
Language: Go
Size: 75.2 KB
Stars: 225
Watchers: 34
Forks: 57
Open Issues: 10
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md

Awesome Lists containing this project

README

# Presto client

A [Presto](https://prestodb.io) client for the [Go](https://golang.org) programming language.

[![Build Status](https://secure.travis-ci.org/prestodb/presto-go-client.png)](http://travis-ci.org/prestodb/presto-go-client)
[![GoDoc](https://godoc.org/github.com/prestodb/presto-go-client?status.svg)](https://godoc.org/github.com/prestodb/presto-go-client)

## Features

* 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

## Requirements

* Go 1.18 or newer
* Presto 0.16x or newer

## Installation

You need a working environment with Go installed and $GOPATH set.

Download and install presto database/sql driver:

```bash
go get github.com/prestodb/presto-go-client/presto
```

Make sure you have Git installed and in your $PATH.

## Usage

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`](https://golang.org/pkg/database/sql/) API then.

Only read operations are supported, such as SHOW and SELECT.

Use `presto` as `driverName` and a valid [DSN](#dsn-data-source-name) as the `dataSourceName`.

Example:

```go
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)
```

### Authentication

HTTP Basic, Kerberos, and JWT authentication are supported.

#### HTTP Basic authentication

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**.

#### Kerberos authentication

This driver supports Kerberos authentication by setting up the Kerberos fields in the [Config](https://godoc.org/github.com/prestodb/presto-go-client/presto#Config) struct.

Please refer to the [Coordinator Kerberos Authentication](https://prestodb.io/docs/current/security/server.html) for server-side configuration.

#### JWT authentication

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.

#### System access control and per-query user information

It's possible to pass user information to presto, different from the principal used to authenticate to the coordinator. See the [System Access Control](https://prestodb.io/docs/current/develop/system-access-control.html) documentation for details.

In order to pass user information in queries to presto, you have to add a [NamedArg](https://godoc.org/database/sql#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:

```go
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.

### DSN (Data Source Name)

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](https://godoc.org/github.com/prestodb/presto-go-client/presto#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

*Parameters are case-sensitive*

Refer to the [Presto Concepts](https://prestodb.io/docs/current/overview/concepts.html) documentation for more information.

##### `source`

```
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.

##### `catalog`

```
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.

##### `schema`

```
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.

##### `session_properties`

```
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.

##### `custom_client`

```
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.

```go
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")
```

#### Examples

```
http://user@localhost:8080?source=hello&catalog=default&schema=foobar
```

```
https://user@localhost:8443?session_properties=query_max_run_time=10m,query_priority=2
```

## License

As described in the [LICENSE](./LICENSE) file.