clickhouse

package module
v1.0.0 Latest Latest
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 Go to latest Published: May 5, 2020 License: GPL-3.0 Imports: 16 Imported by: 4

README

Golang Clickhouse connector

Create new connection

package main

import (
	ch "github.com/leprosus/golang-clickhouse"
)

var (
    user = "clickhouse.user"
    pass = "clickhouse.pass"
    host = "clickhouse.host"
    port = 8123
)

func init(){
    conn := ch.New(host, port, user, pass)
    
    // Also you can preset maximum memory usage limit to execute one query
    conn.MaxMemoryUsage(4 * clickhouse.GigaByte)
}

Query rows

conn := ch.New(host, port, user, pass)

iter, err := conn.Fetch("SELECT `database`, `name`, `engine` FROM system.tables")
if err != nil {
    panic(err)
}

for iter.Next() {
    result := iter.Result

    database, _ := result.String("database")
    name, _ := result.String("name")
    engine, _ := result.String("engine")

    println(database, country, engine)
}

Execute insert

conn := ch.New(host, port, user, pass)

query := fmt.Sprintf("INSERT INTO db.table (SomeFiled) VALUES ('%s')", "Some value")
conn.Exec(query)

Values escaping

value := "Here	is tab. This is line comment --"
escaped := clickhouse.Escape(value)
fmt.Print(escaped) //Here\tis tab. This is line comment \-\-

List all methods

Connection
  • clickhouse.New(host, port, user, pass) - creates connection
  • clickhouse.Debug(func(message string)) - sets custom logger for debug
  • clickhouse.Info(func(message string)) - sets custom logger for info
  • clickhouse.Warn(func(message string)) - sets custom logger for warn
  • clickhouse.Error(func(message string)) - sets custom logger for error
  • clickhouse.Fatal(func(message string)) - sets custom logger for fatal
  • conn.Attempts(attempts, wait) - sets amount of attempts and time awaiting after fail request (wait in seconds)
  • conn.MaxMemoryUsage(limit) - sets maximum memory usage per query (limit in bytes)
  • conn.MaxRequests(limit) - sets maximum requests at the same time
  • conn.ConnectTimeout(timeout) - sets connection timeout (timeout in seconds)
  • conn.SendTimeout(timeout) - sets send timeout (timeout in seconds)
  • conn.ReceiveTimeout(timeout) - sets receive timeout (timeout in seconds)
  • conn.Compression(flag) - sets response compression
Fetching
  • conn.Fetch(query) - executes, fetches query and returns iterator and error
  • conn.ForcedFetch(query) - executes, fetches query and returns iterator and error without requests limits
  • conn.FetchOne(query) - executes, fetches query and returns first result and error
  • conn.ForcedFetchOne(query) - executes, fetches query and returns first result and error without requests limits
  • conn.Exec(query) - executes query and returns error
  • conn.ForcedExec(query) - executes query and returns error without requests limits
Iterator
  • iter.Next() - checks if has more data
  • iter.Err() - returns error if exist or nil
  • iter.Result() - returns result
  • iter.Close() - closes data stream
Result
  • result.Columns() - returns columns list
  • result.Exist("FieldName") - returns true if field is exist or false
  • result.String("FieldName") - returns string value and error
  • result.Bytes("FieldName") - returns bytes slice value and error
  • result.Bool("FieldName") - returns boolean value and error
  • result.UInt8("FieldName") - returns unsigned int8 value and error
  • result.UInt16("FieldName") - returns unsigned int16 value and error
  • result.UInt32("FieldName") - returns unsigned int32 value and error
  • result.UInt64("FieldName") - returns unsigned int64 value and error
  • result.Int8("FieldName") - returns int8 value and error
  • result.Int16("FieldName") - returns int16 value and error
  • result.Int32("FieldName") - returns int32 value and error
  • result.Int64("FieldName") - returns int64 value and error
  • result.Float32("FieldName") - returns float32 value and error
  • result.Float64("FieldName") - returns float64 value and error
  • result.Date("FieldName") - parses data YYYY-MM-DD and returns time value and error
  • result.DateTime("FieldName") - parses data YYYY-MM-DD HH:MM:SS and returns time value and error
Escaping
  • clickhouse.Escape("ValueToEscape") - escapes special symbols
  • clickhouse.Unescape("ValueToUndoEscaping") - undoes escaping of special symbols

Documentation

Index

Constants

View Source 
const (
	MegaByte = 1024 * 1024
	GigaByte = 1024 * MegaByte
)

Variables

This section is empty.

Functions

func Debug 

func Debug(callback func(message string))

Debug sets logger for debug

func Error 

func Error(callback func(message string))

Error sets logger for error

func Escape 

func Escape(line string) string

Escape escapes special symbols

func Fatal 

func Fatal(callback func(message string))

Fatal sets logger for fatal

func Info 

func Info(callback func(message string))

Info sets logger for into

func Unescape 

func Unescape(line string) string

Unescape undoes escaping of special symbols

func Warn 

func Warn(callback func(message string))

Warn sets logger for warning

Types

type Conn 

type Conn struct {
	Limiter
	// contains filtered or unexported fields
}

func New 

func New(host string, port int, user string, pass string) *Conn

func (*Conn) Attempts 

func (conn *Conn) Attempts(amount int, wait int)

Attempts sets amount of attempt query execution

func (*Conn) Compression 

func (conn *Conn) Compression(compression bool)

Compression sets new send timeout

func (*Conn) ConnectTimeout 

func (conn *Conn) ConnectTimeout(timeout int)

ConnectTimeout sets new connection timeout

func (*Conn) Exec 

func (conn *Conn) Exec(query string) error

Exec executes new query

func (*Conn) Fetch 

func (conn *Conn) Fetch(query string) (Iter, error)

Fetch executes new query and fetches all data

func (*Conn) FetchOne 

func (conn *Conn) FetchOne(query string) (Result, error)

FetchOne executes new query and fetches one row

func (*Conn) ForcedExec 

func (conn *Conn) ForcedExec(query string) error

ForcedExec executes new query without requests limits

func (*Conn) ForcedFetch 

func (conn *Conn) ForcedFetch(query string) (Iter, error)

ForcedFetch executes new query and fetches all data without requests limits

func (*Conn) ForcedFetchOne 

func (conn *Conn) ForcedFetchOne(query string) (Result, error)

ForcedFetchOne executes new query and fetches one row without requests limits

func (*Conn) MaxMemoryUsage 

func (conn *Conn) MaxMemoryUsage(limit int)

MaxMemoryUsage sets new maximum memory usage value

func (*Conn) ReceiveTimeout 

func (conn *Conn) ReceiveTimeout(timeout int)

ReceiveTimeout sets new receive timeout

func (*Conn) SendTimeout 

func (conn *Conn) SendTimeout(timeout int)

SendTimeout sets new send timeout

type Iter 

type Iter struct {
	Result Result
	// contains filtered or unexported fields
}

func (Iter) Close 

func (iter Iter) Close()

Close closes stream

func (Iter) Err 

func (iter Iter) Err() error

Err returns error of iterator

func (*Iter) Next 

func (iter *Iter) Next() bool

Next returns next row of data

type Limiter 

type Limiter struct {
	// contains filtered or unexported fields
}

func (*Limiter) MaxRequests 

func (lim *Limiter) MaxRequests(limit int)

MaxRequests sets requests limitation (zero is limitation off)

type Result 

type Result struct {
	// contains filtered or unexported fields
}

func (Result) Bool 

func (result Result) Bool(column string) (f bool, err error)

Bool returns value as bool

func (Result) Bytes 

func (result Result) Bytes(column string) (bytes []byte, err error)

Bytes returns value of bytes

func (Result) Columns 

func (result Result) Columns() (columns []string)

Columns returns columns list

func (Result) Date 

func (result Result) Date(column string) (t time.Time, err error)

Date returns value as date

func (Result) DateTime 

func (result Result) DateTime(column string) (t time.Time, err error)

DateTime returns value as datetime

func (Result) Exist 

func (result Result) Exist(column string) bool

Exist returns true if field is exist or false

func (Result) Float32 

func (result Result) Float32(column string) (f32 float32, err error)

Float32 returns value as float32

func (Result) Float64 

func (result Result) Float64(column string) (f64 float64, err error)

Float64 returns value as float64

func (Result) Int16 

func (result Result) Int16(column string) (i16 int16, err error)

Int16 returns value as int16

func (Result) Int32 

func (result Result) Int32(column string) (i32 int32, err error)

Int32 returns value as int32

func (Result) Int64 

func (result Result) Int64(column string) (i64 int64, err error)

Int64 returns value as int64

func (Result) Int8 

func (result Result) Int8(column string) (i8 int8, err error)

Int8 returns value as int8

func (Result) String 

func (result Result) String(column string) (value string, err error)

String returns value of string

func (Result) UInt16 

func (result Result) UInt16(column string) (ui16 uint16, err error)

UInt16 returns value as uint16

func (Result) UInt32 

func (result Result) UInt32(column string) (ui32 uint32, err error)

UInt32 returns value as uint32

func (Result) UInt64 

func (result Result) UInt64(column string) (ui64 uint64, err error)

UInt64 returns value as uint64

func (Result) UInt8 

func (result Result) UInt8(column string) (ui8 uint8, err error)

UInt8 returns value as uint8

Source Files

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