DB2 AS/400 Querying with Go

I'm trying to connect Golang with an AS/400 DB2 Database, i have iSeries Access Driver Installed on the machine, this is the code by now:

package main

import (
	"odbc"
)

func main() {
	conn, _ := odbc.Connect("DSN=DSN/SCHEME;UID=USER;PWD=PASS")
	stmt, _ := conn.Prepare("SELECT * FROM SCHEME.TABLE")
	stmt.Execute()
	rows, _ := stmt.FetchAll()
	for i, row := range rows {
		println(i, row)
	}
	stmt.Close()
	conn.Close()
}

I was able to do this using Python with a DSN-Less configuration on the ODBC driver with something like this:

con = pyodbc.connect('DRIVER=iSeries Access ODBC Driver;SYSTEM=DSN;UID=USR;PWD=PASS;DBQ=PRUEBA')

I tried on Golang with odbc, mgodbc and db2cli, always getting an invalid memory address or nil pointer dereference error.

Any help is appreciated, Thanks!

Update –
bitbucket.org/phiggins/db2cli is now listed on https://github.com/golang/go/wiki/SQLDrivers

We're using bitbucket.org/phiggins/db2cli, which is based off of the greatcode.google.com/p/odbc library, and it's been working great!

package main

import (
    "database/sql"
    "log"
    "time"

    _ "bitbucket.org/phiggins/db2cli"
)

func main() {
    db, err := sql.Open("db2-cli", "DATABASE=testdb; HOSTNAME=db2.domain.com; PORT=1234; PROTOCOL=TCPIP; UID=user1; PWD=password1;")
    if err != nil {
        log.Fatalln(err)
    }
    defer db.Close()
    var t time.Time
    row := db.QueryRow("SELECT current date FROM sysibm.sysdummy1;")
    err = row.Scan(&t)
    if err != nil {
        log.Fatalln(err)
    }
    log.Println(t)
}

I managed to get it working, first, you need to install mgodbc go package:

go get bitbucket.org/miquella/mgodbc

To install this package you must have a working MinGW installation with gcc on your path (Windows), if you use Linux you should have gcc by installed by default.

Then, using this code i got it working:

package main

import (
	_ "bitbucket.org/miquella/mgodbc"
	"fmt"
	"os"
	"database/sql"
)

var ( 
        db *sql.DB 
        checkError = func(err error, num int) { 
                if err != nil { 
                        fmt.Println(err, num) 
                        os.Exit(1)
                }
        }
) 

func main() {
        // Replace the DBQ value with the name of your ODBC data source.
	db, err := sql.Open("mgodbc", "DRIVER=iSeries Access ODBC Driver;SYSTEM=HOSTNAME;UID=USER;PWD=PASS;DBQ=SCHEMA")
	checkError(err,1)
	rows, err := db.Query("SELECT * FROM TABLE")
	checkError(err,2)
	for rows.Next(){
		fmt.Println(rows)
	}
	defer rows.Close()
	defer db.Close()
}

The only thing missing here, is that sql Go package doesn't cast the Query to String, then you get weird codes when querying, now i'm looking to solve that.

I'm using Go + https://bitbucket.org/phiggins/db2cli.
This go lib for DB2 is using the DB2 CLI driver, that I found here and configured as described on phiggins page: http://public.dhe.ibm.com/ibmdl/export/pub/software/data/db2/drivers/odbc_cli/

Here is my code:

package main

import (
	"fmt"
	_ "bitbucket.org/phiggins/db2cli"
	"database/sql"
	"log"
	"time"
)

func main() {

	// JDBC conn string = jdbc:as400://127.0.0.1/;libraries=MYCUSTOM,hhpgm,trk35null,GX,TRK35B5ptf,TRK35B5PG,IFWMS,INTERTRK;user=MYUSER;password=MYPASS;naming=system;block criteria="0"
	db, err := sql.Open("db2-cli", "DATABASE=MYCUSTOM; HOSTNAME=127.0.0.1; UID=MYUSER; PWD=MYPASS;")
	if err != nil {
		log.Fatalln(err)
	}
	defer db.Close()
	var t time.Time
	row := db.QueryRow("SELECT current date FROM SYSIBM.SYSDUMMY1;")
	err = row.Scan(&t)
	if err != nil {
		log.Fatalln(err)
	}
	log.Println(t)
}

But I'm not being able to connect.
The error that I'm receiving is:

$ go run main.go 
2016/10/27 18:07:46 SQLDriverConnect: {08001} [IBM][CLI Driver] SQL30081N  A communication error has been detected. Communication protocol being used: "TCP/IP".  Communication API being used: "SOCKETS".  Location where the error was detected: "127.0.0.1".  Communication function detecting the error: "connect".  Protocol specific error code(s): "61", "*", "*".  SQLSTATE=08001

exit status 1

I'm on mac, so I identified that the "protocol specific error code" 61 is "#define ECONNREFUSED 61 /* Connection refused */" according to:
http://opensource.apple.com//source/xnu/xnu-1456.1.26/bsd/sys/errno.h

However, I can connect using a SQL client and a JDBC driver.
So, the question is, how can I convert the JDBC connection string to the format expected by the DB2 CLI driver?

• JDBC connection string: jdbc:as400://127.0.0.1/;libraries=MYCUSTOM,hhpgm,trk35null,GX,TRK35B5ptf,TRK35B5PG,IFWMS,INTERTRK;user=MYUSER;password=MYPASS;naming=system;block criteria="0"
• CLI connection string: "HOSTNAME=127.0.0.1; UID=MYUSER; PWD=MYPASS;"

Vanessa, you might need to define the value of the port for your connection string. I not sure what is the default port value so just put it in there to be safe.

Have you tried the golang driver available for Db2?
https://github.com/ibmdb/go_ibm_db