BigQuery Emulator

BigQuery emulator server implemented in Go.
BigQuery emulator provides a way to launch a BigQuery server on your local machine for testing and development.

Features

If you can choose the Go language as BigQuery client, you can launch a BigQuery emulator on the same process as the testing process by httptest .
BigQuery emulator can be built as a static single binary and can be launched as a standalone process. So, you can use the BigQuery emulator from programs written in non-Go languages or such as the bq command, by specifying the address of the launched BigQuery emulator.
BigQuery emulator utilizes SQLite for storage. You can select either memory or file as the data storage destination at startup, and if you set it to file, data can be persisted.
You can load seeds from a YAML file on startup

Install

If Go is installed, you can install the latest version with the following command

$ go install github.com/goccy/bigquery-emulator/cmd/bigquery-emulator@latest

The BigQuery emulator depends on go-zetasql. This library takes a very long time to install because it automatically builds the ZetaSQL library during install. It may look like it hangs because it does not log anything during the build process, but if the clang process is running in the background, it is working fine, so just wait it out. Also, for this reason, the following environment variables must be enabled for installation.

CGO_ENABLED=1
CXX=clang++

You can also download the docker image with the following command

$ docker pull ghcr.io/goccy/bigquery-emulator:latest

You can also download the darwin(amd64) and linux(amd64) binaries directly from releases

How to start the standalone server

If you can install the bigquery-emulator CLI, you can start the server using the following options.

$ ./bigquery-emulator -h
Usage:
  bigquery-emulator [OPTIONS]

Application Options:
      --project=        specify the project name
      --dataset=        specify the dataset name
      --port=           specify the port number (default: 9050)
      --log-level=      specify the log level (debug/info/warn/error) (default: error)
      --log-format=     sepcify the log format (console/json) (default: console)
      --database=       specify the database file if required. if not specified, it will be on memory
      --data-from-yaml= specify the path to the YAML file that contains the initial data
  -v, --version         print version

Help Options:
  -h, --help            Show this help message

Start the server by specifying the project name

$ ./bigquery-emulator --project=test
[bigquery-emulator] listening at 0.0.0.0:9050

If you want to use docker image to start emulator, specify like the following.

$ docker run -it ghcr.io/goccy/bigquery-emulator:latest --project=test

How to use from bq client

1. Start the standalone server

$ ./bigquery-emulator --project=test --data-from-yaml=./server/testdata/data.yaml
[bigquery-emulator] listening at 0.0.0.0:9050

server/testdata/data.yaml is here

2. Call endpoint from bq client

$ bq --api http://0.0.0.0:9050 query --project_id=test "SELECT * FROM dataset1.table_a WHERE id = 1"

+----+-------+
| id | name  |
+----+-------+
|  1 | alice |
+----+-------+

How to use from python client

1. Start the standalone server

$ ./bigquery-emulator --project=test --dataset=dataset1
[bigquery-emulator] listening at 0.0.0.0:9050

2. Call endpoint from python client

Create ClientOptions with api_endpoint option and use AnonymousCredentials to disable authentication.

from google.api_core.client_options import ClientOptions
from google.auth.credentials import AnonymousCredentials
from google.cloud import bigquery
from google.cloud.bigquery import QueryJobConfig

client_options = ClientOptions(api_endpoint="http://0.0.0.0:9050")
client = bigquery.Client(
  "test",
  client_options=client_options,
  credentials=AnonymousCredentials(),
)
client.query(query="...", job_config=QueryJobConfig())

If you use a DataFrame as the download destination for the query results, you have to disable BigQueryStorage client by create_bqstorage_client=False.

https://cloud.google.com/bigquery/docs/samples/bigquery-query-results-dataframe?hl=en

result = client.query(sql).to_dataframe(create_bqstorage_client=False)

Status

BigQuery emulator supports many queries. See here for details.
https://github.com/goccy/go-zetasqlite#status

Synopsis

If you use the Go language as a BigQuery client, you can launch the BigQuery emulator on the same process as the testing process.
Please imports github.com/goccy/bigquery-emulator/server ( and github.com/goccy/bigquery-emulator/types ) and you can use server.New API to create the emulator server instance.

See the API reference for more information: https://pkg.go.dev/github.com/goccy/bigquery-emulator

package main

import (
  "context"
  "fmt"

  "cloud.google.com/go/bigquery"
  "github.com/goccy/bigquery-emulator/server"
  "github.com/goccy/bigquery-emulator/types"
  "google.golang.org/api/iterator"
  "google.golang.org/api/option"
)

func main() {
  ctx := context.Background()
  const (
    projectID = "test"
    datasetID = "dataset1"
    routineID = "routine1"
  )
  bqServer, err := server.New(server.TempStorage)
  if err != nil {
    panic(err)
  }
  if err := bqServer.Load(
    server.StructSource(
      types.NewProject(
        projectID,
        types.NewDataset(
          datasetID,
        ),
      ),
    ),
  ); err != nil {
    panic(err)
  }
  if err := bqServer.SetProject(projectID); err != nil {
    panic(err)
  }
  testServer := bqServer.TestServer()
  defer testServer.Close()

  client, err := bigquery.NewClient(
    ctx,
    projectID,
    option.WithEndpoint(testServer.URL),
    option.WithoutAuthentication(),
  )
  if err != nil {
    panic(err)
  }
  defer client.Close()
  routineName, err := client.Dataset(datasetID).Routine(routineID).Identifier(bigquery.StandardSQLID)
  if err != nil {
    panic(err)
  }
  sql := fmt.Sprintf(`
CREATE FUNCTION %s(
  arr ARRAY<STRUCT<name STRING, val INT64>>
) AS (
  (SELECT SUM(IF(elem.name = "foo",elem.val,null)) FROM UNNEST(arr) AS elem)
)`, routineName)
  job, err := client.Query(sql).Run(ctx)
  if err != nil {
    panic(err)
  }
  status, err := job.Wait(ctx)
  if err != nil {
    panic(err)
  }
  if err := status.Err(); err != nil {
    panic(err)
  }

  it, err := client.Query(fmt.Sprintf(`
SELECT %s([
  STRUCT<name STRING, val INT64>("foo", 10),
  STRUCT<name STRING, val INT64>("bar", 40),
  STRUCT<name STRING, val INT64>("foo", 20)
])`, routineName)).Read(ctx)
  if err != nil {
    panic(err)
  }

  var row []bigquery.Value
  if err := it.Next(&row); err != nil {
    if err == iterator.Done {
        return
    }
    panic(err)
  }
  fmt.Println(row[0]) // 30
}

How it works