Go (ADBC)

The Hardcharger™ ADBC driver is written in Go, so Go programs use it directly, as a package, with no driver manager and no cgo:

go get github.com/gizmodata/hardcharger-adbc/go/v2

Query

package main

import (
  "context"
  "fmt"
  "log"

  "github.com/apache/arrow-go/v18/arrow/array"
  "github.com/apache/arrow-go/v18/arrow/memory"
  "github.com/gizmodata/hardcharger-adbc/go/v2/hardcharger"
)

func main() {
  ctx := context.Background()
  db, err := hardcharger.NewDriver(memory.DefaultAllocator).NewDatabaseWithContext(ctx, map[string]string{
    "uri":                      "hardcharger://localhost?tls=false",
    "username":                 "hardcharger",
    "password":                 "change-me",
    hardcharger.OptionQueryTag: `{"app": "report.go"}`,
  })
  if err != nil {
    log.Fatal(err)
  }
  defer db.Close(ctx)
  cnxn, err := db.Open(ctx)
  if err != nil {
    log.Fatal(err)
  }
  defer cnxn.Close(ctx)

  stmt, err := cnxn.NewStatement(ctx)
  if err != nil {
    log.Fatal(err)
  }
  defer stmt.Close(ctx)
  if err := stmt.SetSqlQuery(ctx, "SELECT i, i * i AS square FROM range(1, 4) t(i) ORDER BY i"); err != nil {
    log.Fatal(err)
  }
  reader, _, err := stmt.ExecuteQuery(ctx)
  if err != nil {
    log.Fatal(err)
  }
  defer reader.Release()
  for reader.Next() {
    batch := reader.RecordBatch()
    squares := batch.Column(1).(*array.Int64)
    for row := 0; row < int(batch.NumRows()); row++ {
      fmt.Println(squares.Value(row))
    }
  }
  if err := reader.Err(); err != nil {
    log.Fatal(err)
  }
}

1
4
9

The reader streams record batches as they arrive; release it when you’re done, which also tells the server it can drop the result.

Options

The database and connection options are the same in every ADBC language:

Option	Meaning
uri	hardcharger://host[:port][/prefix][?tls=false], or warp://, https://, http://
username, password	Password sign-in (token with an ID token as the password for SSO)
adbc.hardcharger.query_tag, adbc.hardcharger.session_tag	JSON tags recorded in instrumentation
adbc.hardcharger.setting.NAME	SET SESSION hardcharger.NAME on every session (database) or now (connection)
adbc.hardcharger.global_setting.NAME	SET GLOBAL hardcharger.NAME (administrators)
adbc.hardcharger.auth_type	external for browser sign-in
adbc.warp.tls.root_certs, adbc.warp.tls.client_cert, adbc.warp.tls.client_key	TLS: a private CA, mutual TLS
adbc.warp.statement.result_partitions, adbc.warp.statement.result_order	Partitioned results
adbc.warp.ipc_compression	zstd
adbc.warp.statement.async, adbc.warp.statement.retain_result	Submit, poll, fetch; resumable results
adbc.warp.statement.timeout_seconds	Per-statement timeout

The Go package exports the Hardcharger names as constants (hardcharger.OptionQueryTag, …). Bind parameters with stmt.Bind or stmt.BindStream; bulk-load with the standard adbc.ingest.target_table and adbc.ingest.mode options and BindStream.

Errors

Errors are adbc.Error values with the SQLSTATE and the server’s message. warpsql.ErrorCode(err) (from github.com/gizmodata/warp-sql-adbc/go/warpsql) returns the server’s stable error code (sql_error, session_not_found, …) behind any error the driver returns. Cancel a running statement by cancelling its context.