README

********************************************************************************
Go Snowflake Driver
********************************************************************************

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This topic provides instructions for installing, running, and modifying the Go Snowflake Driver. The driver supports Go's `database/sql <https://golang.org/pkg/database/sql/>`_ package.

Prerequisites
================================================================================

The following software packages are required to use the Go Snowflake Driver.

Go
----------------------------------------------------------------------

The latest driver requires the `Go language <https://golang.org/>`_ 1.13 or higher. The supported operating systems are Linux, Mac OS, and Windows, but you may run the driver on other platforms if the Go language works correctly on those platforms.


Installation
================================================================================

Get Gosnowflake source code, if not installed.

.. code-block:: bash

    go get -u github.com/snowflakedb/gosnowflake

Docs
====

For detailed documentation and basic usage examples, please see the documentation at
`godoc.org <https://godoc.org/github.com/snowflakedb/gosnowflake/>`_.

Sample Programs
================================================================================

Snowflake provides a set of sample programs to test with. Set the environment variable ``$GOPATH`` to the top directory of your workspace, e.g., ``~/go`` and make certain to 
include ``$GOPATH/bin`` in the environment variable ``$PATH``. Run the ``make`` command to build all sample programs.

.. code-block:: go

    make install

In the following example, the program ``select1.go`` is built and installed in ``$GOPATH/bin`` and can be run from the command line:

.. code-block:: bash

    SNOWFLAKE_TEST_ACCOUNT=<your_account> \
    SNOWFLAKE_TEST_USER=<your_user> \
    SNOWFLAKE_TEST_PASSWORD=<your_password> \
    select1
    Congrats! You have successfully run SELECT 1 with Snowflake DB!

Development
================================================================================

The developer notes are hosted with the source code on `GitHub <https://github.com/snowflakedb/gosnowflake>`_.

Testing Code
----------------------------------------------------------------------

Set the Snowflake connection info in ``parameters.json``:

.. code-block:: json

    {
        "testconnection": {
            "SNOWFLAKE_TEST_USER":      "<your_user>",
            "SNOWFLAKE_TEST_PASSWORD":  "<your_password>",
            "SNOWFLAKE_TEST_ACCOUNT":   "<your_account>",
            "SNOWFLAKE_TEST_WAREHOUSE": "<your_warehouse>",
            "SNOWFLAKE_TEST_DATABASE":  "<your_database>",
            "SNOWFLAKE_TEST_SCHEMA":    "<your_schema>",
            "SNOWFLAKE_TEST_ROLE":      "<your_role>"
        }
    }

Install `jq <https://stedolan.github.io/jq/>`_ so that the parameters can get parsed correctly, and run ``make test`` in your Go development environment:

.. code-block:: bash

    make test

Submitting Pull Requests
----------------------------------------------------------------------

You may use your preferred editor to edit the driver code. Make certain to run ``make fmt lint`` before submitting any pull request to Snowflake. This command formats your source code according to the standard Go style and detects any coding style issues.

Support
----------------------------------------------------------------------

For official support, contact Snowflake support at:
https://support.snowflake.net/

Expand ▾ Collapse ▴

Documentation

Overview

Package gosnowflake is a pure Go Snowflake driver for the database/sql package.

Clients can use the database/sql package directly. For example:

import (
	"database/sql"

	_ "github.com/snowflakedb/gosnowflake"
)

func main() {
	db, err := sql.Open("snowflake", "user:password@myaccount/mydb")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()
	...
}

Connection String

Use Open to create a database handle with connection parameters:

db, err := sql.Open("snowflake", "<connection string>")

The Go Snowflake Driver supports the following connection syntaxes (or data source name formats):

* username[:password]@accountname/dbname/schemaname[?param1=value&...&paramN=valueN
* username[:password]@accountname/dbname[?param1=value&...&paramN=valueN
* username[:password]@hostname:port/dbname/schemaname?account=<your_account>[&param1=value&...&paramN=valueN]

where all parameters must be escaped or use `Config` and `DSN` to construct a DSN string.

The following example opens a database handle with the Snowflake account myaccount where the username is jsmith, password is mypassword, database is mydb, schema is testschema, and warehouse is mywh:

db, err := sql.Open("snowflake", "jsmith:mypassword@myaccount/mydb/testschema?warehouse=mywh")

Connection Parameters

The following connection parameters are supported:

	* account <string>: Specifies the name of your Snowflake account, where string is the name
		assigned to your account by Snowflake. In the URL you received from
		Snowflake, your account name is the first segment in the domain (e.g.
		abc123 in https://abc123.snowflakecomputing.com). This parameter is
		optional if your account is specified after the @ character. If you
		are not on us-west-2 region or AWS deployment, then append the region
		after the account name, e.g. “<account>.<region>”. If you are not on
		AWS deployment, then append not only the region, but also the platform,
		e.g., “<account>.<region>.<platform>”. Account, region, and platform
		should be separated by a period (“.”), as shown above. If you are using
        a global url, then append connection group and "global",
        e.g., "account-<connection_group>.global". Account and connection group are
        separated by a dash ("-"), as shown above.

	* region <string>: DEPRECATED. You may specify a region, such as
		“eu-central-1”, with this parameter. However, since this parameter
		is deprecated, it is best to specify the region as part of the
		account parameter. For details, see the description of the account
		parameter.

	* database: Specifies the database to use by default in the client session
		(can be changed after login).

	* schema: Specifies the database schema to use by default in the client
		session (can be changed after login).

	* warehouse: Specifies the virtual warehouse to use by default for queries,
		loading, etc. in the client session (can be changed after login).

	* role: Specifies the role to use by default for accessing Snowflake
		objects in the client session (can be changed after login).

	* passcode: Specifies the passcode provided by Duo when using MFA for login.

	* passcodeInPassword: false by default. Set to true if the MFA passcode is
		embedded in the login password. Appends the MFA passcode to the end of the
		password.

	* loginTimeout: Specifies the timeout, in seconds, for login. The default
		is 60 seconds. The login request gives up after the timeout length if the
		HTTP response is success.

	* authenticator: Specifies the authenticator to use for authenticating user credentials:
		- To use the internal Snowflake authenticator, specify snowflake (Default).
		- To authenticate through Okta, specify https://<okta_account_name>.okta.com (URL prefix for Okta).
		- To authenticate using your IDP via a browser, specify externalbrowser.
		- To authenticate via OAuth, specify oauth and provide an OAuth Access Token (see the token parameter below).

	* application: Identifies your application to Snowflake Support.

	* insecureMode: false by default. Set to true to bypass the Online
		Certificate Status Protocol (OCSP) certificate revocation check.
		IMPORTANT: Change the default value for testing or emergency situations only.

	* token: a token that can be used to authenticate. Should be used in conjunction with the "oauth" authenticator.

	* client_session_keep_alive: Set to true have a heartbeat in the background every hour to keep the connection alive
		such that the connection session will never expire. Care should be taken in using this option as it opens up
		the access forever as long as the process is alive.

	* ocspFailOpen: true by default. Set to false to make OCSP check fail closed mode.

	* validateDefaultParameters: true by default. Set to false to disable checks on existence and privileges check for
								 Database, Schema, Warehouse and Role when setting up the connection

All other parameters are taken as session parameters. For example, TIMESTAMP_OUTPUT_FORMAT session parameter can be set by adding:

...&TIMESTAMP_OUTPUT_FORMAT=MM-DD-YYYY...

Proxy

The Go Snowflake Driver honors the environment variables HTTP_PROXY, HTTPS_PROXY and NO_PROXY for the forward proxy setting.

NO_PROXY specifies which hostname endings should be allowed to bypass the proxy server, e.g. :code:`no_proxy=.amazonaws.com` means that AWS S3 access does not need to go through the proxy.

NO_PROXY does not support wildcards. Each value specified should be one of the following:

* The end of a hostname (or a complete hostname), for example: ".amazonaws.com" or "xy12345.snowflakecomputing.com".

* An IP address, for example "192.196.1.15".

If more than one value is specified, values should be separated by commas, for example:

no_proxy=localhost,.my_company.com,xy12345.snowflakecomputing.com,192.168.1.15,192.168.1.16

Logging

By default, the driver's builtin logger is NOP; no output is generated. This is intentional for those applications that use the same set of logger parameters not to conflict with glog, which is incorporated in the driver logging framework.

In order to enable debug logging for the driver, add a build tag sfdebug to the go tool command lines, for example:

go build -tags=sfdebug

In your application, you will need to import the "flag" module, and include code to enable the logging. For example:

if !flag.Parsed() {
        // enable glog for Go Snowflake Driver
        flag.Parse()
}

For tests, run the test command with the tag along with glog parameters. For example, the following command will generate all acitivty logs in the standard error.

go test -tags=sfdebug -v . -vmodule=*=2 -stderrthreshold=INFO

Likewise, if you build your application with the tag, you may specify the same set of glog parameters.

your_go_program -vmodule=*=2 -stderrthreshold=INFO

Using the -stderrthreshold option will result in logging being shown in the STDERR of the executing shell. If you wish to have the logging in a file, then you may use the -log_dir option, and give it a path to a directory where log files will be made.

your_go_program -vmodule=*=2 -log_dir=/path/to/logs

The -stderrthreshold option and the -log_dir option may also be used at the same time, and the log data will be put in both places.

your_go_program -vmodule=*=2 -stderrthreshold=INFO -log_dir=/path/to/logs

To get the logs for a specific module, use the -vmodule option. For example, to retrieve the driver.go and connection.go module logs:

your_go_program -vmodule=driver=2,connection=2 -stderrthreshold=INFO

Note: If your request retrieves no logs, call db.Close() or glog.flush() to flush the glog buffer.

Note: The logger may be changed in the future for better logging. Currently if the applications use the same parameters as glog, you cannot collect both application and driver logs at the same time.

Canceling Query by CtrlC

From 0.5.0, a signal handling responsibility has moved to the applications. If you want to cancel a query/command by Ctrl+C, add a os.Interrupt trap in context to execute methods that can take the context parameter, e.g., QueryContext, ExecContext.

// handle interrupt signal
ctx, cancel := context.WithCancel(context.Background())
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt)
defer func() {
	signal.Stop(c)
}()
go func() {
	select {
	case <-c:
		cancel()
	case <-ctx.Done():
	}
}()
... (connection)
// execute a query
rows, err := db.QueryContext(ctx, query)
... (Ctrl+C to cancel the query)

See cmd/selectmany.go for the full example.

Supported Data Types

Queries return SQL column type information in the ColumnType type. The DatabaseTypeName method returns strings representing Snowflake data types. The following table shows those strings, the corresponding Snowflake data type, and the corresponding Golang native data type:

String Representation	Snowflake Data Type	Golang Data Type
---------------------   -------------------	-----------------------
FIXED	                NUMBER/INT              int64 , int32, int16, int8, int
REAL	                REAL                    float64, float32
TEXT	                VARCHAR/STRING          string
DATE	                DATE                    time.Time
TIME	                TIME                    time.Time
TIMESTAMP_LTZ	        TIMESTAMP_LTZ           time.Time
TIMESTAMP_NTZ	        TIMESTAMP_NTZ           time.Time
TIMESTAMP_TZ	        TIMESTAMP_TZ            time.Time
VARIANT	                VARIANT                 string
OBJECT	                OBJECT                  string
ARRAY	                ARRAY                   string
BINARY	                BINARY                  []byte
BOOLEAN	                BOOLEAN                 bool

Binding Time Type

Go's database/sql package limits Go's data types to the following for binding and fetching:

int64
float64
bool
[]byte
string
time.Time

Fetching data isn't an issue since the database data type is provided along with the data so the Go Snowflake Driver can translate Snowflake data types to Go native data types.

When the client binds data to send to the server, however, the driver cannot determine the date/timestamp data types to associate with binding parameters. For example:

dbt.mustExec("CREATE OR REPLACE TABLE tztest (id int, ntz, timestamp_ntz, ltz timestamp_ltz)")
// ...
stmt, err :=dbt.db.Prepare("INSERT INTO tztest(id,ntz,ltz) VALUES(1, ?, ?)")
// ...
tmValue time.Now()
// ... Is tmValue a TIMESTAMP_NTZ or TIMESTAMP_LTZ?
_, err = stmt.Exec(tmValue, tmValue)

To resolve this issue, a binding parameter flag is introduced that associates any subsequent time.Time type to the DATE, TIME, TIMESTAMP_LTZ, TIMESTAMP_NTZ or BINARY data type. The above example could be rewritten as follows:

import (
	sf "github.com/snowflakedb/gosnowflake"
)
dbt.mustExec("CREATE OR REPLACE TABLE tztest (id int, ntz, timestamp_ntz, ltz timestamp_ltz)")
// ...
stmt, err :=dbt.db.Prepare("INSERT INTO tztest(id,ntz,ltz) VALUES(1, ?, ?)")
// ...
tmValue time.Now()
// ...
_, err = stmt.Exec(sf.DataTypeTimestampNtz, tmValue, sf.DataTypeTimestampLtz, tmValue)

Timestamps with Time Zones

The driver fetches TIMESTAMP_TZ (timestamp with time zone) data using the offset-based Location types, which represent a collection of time offsets in use in a geographical area, such as CET (Central European Time) or UTC (Coordinated Universal Time). The offset-based Location data is generated and cached when a Go Snowflake Driver application starts, and if the given offset is not in the cache, it is generated dynamically.

Currently, Snowflake doesn't support the name-based Location types, e.g., America/Los_Angeles.

For more information about Location types, see the Go documentation for https://golang.org/pkg/time/#Location.

Binary Data

Internally, this feature leverages the []byte data type. As a result, BINARY data cannot be bound without the binding parameter flag. In the following example, sf is an alias for the gosnowflake package:

var b = []byte{0x01, 0x02, 0x03}
_, err = stmt.Exec(sf.DataTypeBinary, b)

Maximum number of Result Set Chunk Downloader

The driver directly downloads a result set from the cloud storage if the size is large. It is required to shift workloads from the Snowflake database to the clients for scale. The download takes place by goroutine named "Chunk Downloader" asynchronously so that the driver can fetch the next result set while the application can consume the current result set.

The application may change the number of result set chunk downloader if required. Note this doesn't help reduce memory footprint by itself. Consider Custom JSON Decoder.

import (
	sf "github.com/snowflakedb/gosnowflake"
)
sf.MaxChunkDownloadWorkers = 2

Experimental: Custom JSON Decoder for parsing Result Set

The application may have the driver use a custom JSON decoder that incrementally parses the result set as follows.

import (
	sf "github.com/snowflakedb/gosnowflake"
)
sf.CustomJSONDecoderEnabled = true
...

This option will reduce the memory footprint to half or even quarter, but it can significantly degrade the performance depending on the environment. The test cases running on Travis Ubuntu box show five times less memory footprint while four times slower. Be cautious when using the option.

(Private Preview) JWT authentication

** Not recommended for production use until GA

Now JWT token is supported when compiling with a golang version of 1.10 or higher. Binary compiled with lower version of golang would return an error at runtime when users try to use JWT authentication feature.

To enable this feature, one can construct DSN with fields "authenticator=SNOWFLAKE_JWT&privateKey=<your_private_key>", or using Config structure specifying:

config := &Config{
	...
	Authenticator: "SNOWFLAKE_JWT"
	PrivateKey:   "<your_private_key_struct in *rsa.PrivateKey type>"
}

The <your_private_key> should be a base64 URL encoded PKCS8 rsa private key string. One way to encode a byte slice to URL base 64 URL format is through base64.URLEncoding.EncodeToString() function.

On the server side, one can alter the public key with the SQL command:

ALTER USER <your_user_name> SET RSA_PUBLIC_KEY='<your_public_key>';

The <your_public_key> should be a base64 Standard encoded PKI public key string. One way to encode a byte slice to base 64 Standard format is through base64.StdEncoding.EncodeToString() function.

To generate the valid key pair, one can do the following command on the shell script:

	# generate 2048-bit pkcs8 encoded RSA private key
	openssl genpkey -algorithm RSA \
    	-pkeyopt rsa_keygen_bits:2048 \
    	-pkeyopt rsa_keygen_pubexp:65537 | \
  		openssl pkcs8 -topk8 -outform der > rsa-2048-private-key.p8

	# extravt 2048-bit PKI encoded RSA public key from the private key
	openssl pkey -pubout -inform der -outform der \
    	-in rsa-2048-private-key.p8 \
    	-out rsa-2048-public-key.spki

Note: As of Feb 2020, Golang's official library does not support passcode-encrypted PKCS8 private key. For security purposes, Snowflake highly recommends that you store the passcode-encrypted private key on the disk and decrypt the key in your application using a library you trust.

Executing Multiple Statements in One Call

Note: This feature is in preview. It is available to all accounts, but it is intended for development work, not production work. This feature is first available in version 1.3.7 of the driver.

By default, Snowflake returns an error for queries issued with multiple statements. This restriction helps protect against SQL Injection attacks (https://en.wikipedia.org/wiki/SQL_injection).

The multi-statement feature allows users skip this restriction and execute multiple SQL statements through a single Golang function call. However, this opens up the possibility for SQL injection, so it should be used carefully. The risk can be reduced by specifying the exact number of statements to be executed, which makes it more difficult to inject a statement by appending it. More details are below.

The Go Snowflake Driver provides two functions that can execute multiple SQL statements in a single call:

* db.QueryContext(): This function is used to execute queries, such as SELECT statements, that return a result set. * db.ExecContext(): This function is used to execute statements that don't return a result set (i.e. most DML and DDL statements).

To compose a multi-statement query, simply create a string that contains all the queries, separated by semicolons, in the order in which the statements should be executed.

To protect against SQL Injection attacks while using the multi-statement feature, pass a Context that specifies the number of statements in the string. For example:

import (
	"context"
	"database/sql"
)

var multi_statement_query = "SELECT c1 FROM t1; SELECT c2 FROM t2"
var number_of_statements = 2
blank_context = context.Background()
multi_statement_context, _ := WithMultiStatement(blank_context, number_of_statements)
rows, err := db.QueryContext(multi_statement_context, multi_statement_query)

When multiple queries are executed by a single call to QueryContext(), multiple result sets are returned. After you process the first result set, get the next result set (for the next SQL statement) by calling NextResultSet().

The following pseudo-code shows how to process multiple result sets:

Execute the statement and get the result set(s):

	rows, err := db.QueryContext(ctx, multiStmtQuery)

Retrieve the rows in the first query's result set:

	while rows.Next() {
		err = rows.Scan(&variable_1)
		if err != nil {
			t.Errorf("failed to scan: %#v", err)
		}
		...
	}

Retrieve the remaining result sets and the rows in them:

	while rows.NextResultSet()  {

		while rows.Next() {
			...
		}

	}

The function db.execContext() returns a single result, which is the sum of the results of the individual statements. For example, if your multi-statement query executed two UPDATE statements, each of which updated 10 rows, then the result returned would be 20. Individual results for individual statements are not available.

The following code shows how to retrieve the result of a multi-statement query executed through db.ExecContext():

Execute the SQL statements:

    res, err := db.ExecContext(ctx, multiStmtQuery)

Get the summed result and store it in the variable named count:

    count, err := res.RowsAffected()

Note: Because a multi-statement ExecContext() returns a single value, you cannot detect offsetting errors. For example, suppose you expected the return value to be 20 because you expected each UPDATE statement to update 10 rows. If one UPDATE statement updated 15 rows and the other UPDATE statement updated only 5 rows, the total would still be 20. You would see no indication that the UPDATES had not functioned as expected.

The ExecContext() function does not return an error if passed a query (e.g. a SELECT statement). However, it still returns only a single value, not a result set, so using it to execute queries (or a mix of queries and non-query statements) is impractical.

The QueryContext() function does not return an error if passed non-query statements (e.g. DML). The function returns a result set for each statement, whether or not the statement is a query. For each non-query statement, the result set contains a single row that contains a single column; the value is the number of rows changed by the statement.

If you want to execute a mix of query and non-query statements (e.g. a mix of SELECT and DML statements) in a multi-statement query, use QueryContext(). You can retrieve the result sets for the queries, and you can retrieve or ignore the row counts for the non-query statements.

If any of the SQL statements fail to compile or execute, execution is aborted. Any previous statements that ran before are unaffected.

For example, if the statements below are run as one multi-statement query, the multi-statement query fails on the third statement, and an exception is thrown.

CREATE OR REPLACE TABLE test(n int);
INSERT INTO TEST VALUES (1), (2);
INSERT INTO TEST VALUES ('not_an_integer');  -- execution fails here
INSERT INTO TEST VALUES (3);

If you then query the contents of the table named "test", the values 1 and 2 would be present.

When using the QueryContext() and ExecContext() functions, golang code can check for errors the usual way. For example:

rows, err := db.QueryContext(ctx, multiStmtQuery)
if err != nil {
	Fatalf("failed to query multiple statements: %v", err)
}

Preparing statements and using bind variables are also not supported for multi-statement queries.

Using Arrow Data Transfer Format

Note: This feature is in preview. It is available to all accounts, but it is intended for development work, not production work. This feature is first available in version 1.3.4 of the driver.

The Go Snowflake Driver supports the Arrow data format, which can improve performance and reduce memory consumption when transferring data between Snowflake and Golang clients.

Historically, the Go Snowflake Driver used the JSON data format when transferring data between Snowflake and the Golang client. The Arrow data format avoids the JSON format's extra conversions between binary and textual representations of the data.

The data format is controlled by the session-level Snowflake parameter GO_QUERY_RESULT_FORMAT. For more information about Snowflake parameters, see https://docs.snowflake.com/en/sql-reference/parameters.html.

To use Arrow format, execute:

ALTER SESSION SET GO_QUERY_RESULT_FORMAT = 'ARROW';

To use JSON format, execute:

ALTER SESSION SET GO_QUERY_RESULT_FORMAT = 'JSON';

The valid values for the parameter are:

ARROW
JSON

The default value is 'JSON'. The default will change in the future.

If the user attempts to set the parameter to an invalid value, an error is returned.

Neither the parameter name nor the parameter value is case-sensitive.

This parameter can be set only at the session level.

While using this feature, keep in mind the following:

* The Arrow data format can reduce rounding errors in floating point numbers. You might see slightly different
   values for floating point numbers when using Arrow format than in JSON format.

* For some numeric data types, the driver can retrieve larger values when using the Arrow format than when using the
  JSON format. For example, using Arrow format allows the full range of SQL NUMERIC(38,0) values to be retrieved,
  while using JSON format allows only values in the range supported by the Golang int64 data type.

  Users should ensure that Golang variables are declared using the appropriate data type for the full range of values
  contained in the column. For an example, see the description below on how to extract big values.

When using the Arrow format, the driver supports more Golang data types and more ways to convert SQL values to those Golang data types than when using JSON format.

The table below lists the supported Snowflake SQL data types and the corresponding Golang data types. The columns are:

1. The SQL data type.
2. The default Golang data type that is returned when you use snowflakeRows.Scan() to read data from
   Arrow data format via an interface{}.
3. The possible Golang data types that can be returned when you use snowflakeRows.Scan() to read data from
   Arrow data format directly.
4. The default Golang data type that is returned when you use snowflakeRows.Scan() to read data from
   JSON data format via an interface{}. (All returned values are JSON strings.)
5. The standard Golang data type that is returned when you use snowflakeRows.Scan() to read data from
   JSON data format directly.
6. Footnotes numbers.

This table shows the data types:

====================================================================================================================================
                                  | Default Go  | Supported Go                             | Default Go  | Supported  |
                                  | Data Type   | Data Types                               | Data Type   | Go Data    |
SQL Data Type                     | for Scan()  | for Scan()                               | for Scan()  | Types for  | Footnotes
                                  | interface{} | (ARROW)                                  | interface{} | Scan()     |
                                  | (ARROW)     |                                          | (JSON)      | (JSON)     |
=====================================================================================================================================
BOOLEAN                           | bool        | bool                                     | string      | bool       |
VARCHAR                           | string      | string                                   | string      | string     |
DOUBLE                            | float64     | float32, float64                         | string      | float64    | [1]  [2]
INTEGER that fits in int64        | int64       | int, int8, int16, int32, int64           | string      | int64      | [1]  [2]
INTEGER that doesn't fit in int64 | *big.Int    | int, int8, int16, int32, int64, *big.Int | string      |            | [1]  [3]  [5]
NUMBER(P, S) where S > 0          | *big.Float  | float32, float64, *big.Float             | string      |            | [1]  [4]  [5]
DATE                              | time.Time   | time.Time                                | string      | time.Time  |
TIME                              | time.Time   | time.Time                                | string      | time.Time  |
TIMESTAMP_LTZ                     | time.Time   | time.Time                                | string      | time.Time  |
TIMESTAMP_NTZ                     | time.Time   | time.Time                                | string      | time.Time  |
TIMESTAMP_TZ                      | time.Time   | time.Time                                | string      | time.Time  |
BINARY                            | []byte      | []byte                                   | string      | []byte     |
ARRAY                             | string      | string                                   | string      | string     |
OBJECT                            | string      | string                                   | string      | string     |
VARIANT                           | string      | string                                   | string      | string     |

Footnotes:

[1] Converting from a higher precision data type to a lower precision data type via the snowflakeRows.Scan() method can lose low bits (lose precision), lose high bits (completely change the value), or result in error.

[2] Attempting to convert from a higher precision data type to a lower precision data type via interface{} causes an error.

[3] You cannot directly Scan() into the alternative data types via snowflakeRows.Scan(), but can convert to those data types by using .Int64()/.String()/.Uint64() methods. For an example, see the description below
    on extracting big values.

[4] You cannot directly Scan() into the alternative data types via snowflakeRows.Scan(), but can convert to those data types by using .Float32()/.String()/.Float64() methods. For an example, see the description below
    on extracting big values.

[5] Returns either an int64 with the high bits truncated or an error.

This example shows how to retrieve very large values using the math/big package. This example retrieves a large INTEGER value to an interface and then extracts a big.Int value from that interface. If the value fits into an int64, then the code also copies the value to a variable of type int64.

import math/big

...

var my_interface interface{}
var my_big_int_pointer *big.Int
var my_int64 int64
var rows snowflakeRows

...

rows.Scan(&my_interface)
my_big_int_pointer, ok = my_interface.(*big.Int)
if my_big_int_pointer.IsInt64() {
    my_int64 = my_big_int_pointer.Int64()
}

If the variable named "rows" is known to contain a big.Int, then you can use the following instead of scanning into an interface and then converting to a big.Int:

rows.Scan(&my_big_int_pointer)

If the variable named "rows" contains a big.Int, then each of the following fails:

rows.Scan(&my_int64)

my_int64, ok = my_interface.(int64)

Similar code and rules also apply to big.Float values.

If you're not sure what data type will be returned, you can use code similar to the following to check the data type of the returned value:

// Create variables into which we can scan the returned values.
var i64 int64
var bigIntPtr *big.Int

for rows.Next() {
    // Get the data type info.
    column_types, err := rows.ColumnTypes()
    if err != nil {
        log.Fatalf("ERROR: ColumnTypes() failed. err: %v", err)
    }
    // The data type of the zeroeth column in the row.
    column_type := column_types[0].ScanType()
    // Choose the appropriate variable based on the data type.
    switch column_type {
        case reflect.TypeOf(i64):
            err = rows.Scan(&i64)
            fmt.Println("INFO: retrieved int64 value:")
            fmt.Println(i64)
        case reflect.TypeOf(bigIntPtr):
            err = rows.Scan(&bigIntPtr)
            fmt.Println("INFO: retrieved bigIntPtr value:")
            fmt.Println(bigIntPtr)
    }
}

Note: SQL NULL values are converted to Golang nil values, and vice-versa.

Limitations

GET and PUT operations are unsupported.

Index

Constants

const (

	// ErrCodeEmptyAccountCode is an error code for the case where a DNS doesn't include account parameter
	ErrCodeEmptyAccountCode = 260000
	// ErrCodeEmptyUsernameCode is an error code for the case where a DNS doesn't include user parameter
	ErrCodeEmptyUsernameCode = 260001
	// ErrCodeEmptyPasswordCode is an error code for the case where a DNS doesn't include password parameter
	ErrCodeEmptyPasswordCode = 260002
	// ErrCodeFailedToParseHost is an error code for the case where a DNS includes an invalid host name
	ErrCodeFailedToParseHost = 260003
	// ErrCodeFailedToParsePort is an error code for the case where a DNS includes an invalid port number
	ErrCodeFailedToParsePort = 260004
	// ErrCodeIdpConnectionError is an error code for the case where a IDP connection failed
	ErrCodeIdpConnectionError = 260005
	// ErrCodeSSOURLNotMatch is an error code for the case where a SSO URL doesn't match
	ErrCodeSSOURLNotMatch = 260006
	// ErrCodeServiceUnavailable is an error code for the case where service is unavailable.
	ErrCodeServiceUnavailable = 260007
	// ErrCodeFailedToConnect is an error code for the case where a DB connection failed due to wrong account name
	ErrCodeFailedToConnect = 260008
	// ErrCodeRegionOverlap is an error code for the case where a region is specified despite an account region present
	ErrCodeRegionOverlap = 260009
	// ErrCodePrivateKeyParseError is an error code for the case where the private key is not parsed correctly
	ErrCodePrivateKeyParseError = 260010
	// ErrCodeFailedToParseAuthenticator is an error code for the case where a DNS includes an invalid authenticator
	ErrCodeFailedToParseAuthenticator = 260011

	// ErrFailedToPostQuery is an error code for the case where HTTP POST failed.
	ErrFailedToPostQuery = 261000
	// ErrFailedToRenewSession is an error code for the case where session renewal failed.
	ErrFailedToRenewSession = 261001
	// ErrFailedToCancelQuery is an error code for the case where cancel query failed.
	ErrFailedToCancelQuery = 261002
	// ErrFailedToCloseSession is an error code for the case where close session failed.
	ErrFailedToCloseSession = 261003
	// ErrFailedToAuth is an error code for the case where authentication failed for unknown reason.
	ErrFailedToAuth = 261004
	// ErrFailedToAuthSAML is an error code for the case where authentication via SAML failed for unknown reason.
	ErrFailedToAuthSAML = 261005
	// ErrFailedToAuthOKTA is an error code for the case where authentication via OKTA failed for unknown reason.
	ErrFailedToAuthOKTA = 261006
	// ErrFailedToGetSSO is an error code for the case where authentication via OKTA failed for unknown reason.
	ErrFailedToGetSSO = 261007
	// ErrFailedToParseResponse is an error code for when we cannot parse an external browser response from Snowflake.
	ErrFailedToParseResponse = 261008
	// ErrFailedToGetExternalBrowserResponse is an error code for when there's an error reading from the open socket.
	ErrFailedToGetExternalBrowserResponse = 261009
	// ErrFailedToHeartbeat is an error code when a heartbeat fails.
	ErrFailedToHeartbeat = 261010

	// ErrFailedToGetChunk is an error code for the case where it failed to get chunk of result set
	ErrFailedToGetChunk = 262000

	// ErrNoReadOnlyTransaction is an error code for the case where readonly mode is specified.
	ErrNoReadOnlyTransaction = 263000
	// ErrNoDefaultTransactionIsolationLevel is an error code for the case where non default isolation level is specified.
	ErrNoDefaultTransactionIsolationLevel = 263001

	// ErrInvalidTimestampTz is an error code for the case where a returned TIMESTAMP_TZ internal value is invalid
	ErrInvalidTimestampTz = 268000
	// ErrInvalidOffsetStr is an error code for the case where a offset string is invalid. The input string must
	// consist of sHHMI where one sign character '+'/'-' followed by zero filled hours and minutes
	ErrInvalidOffsetStr = 268001
	// ErrInvalidBinaryHexForm is an error code for the case where a binary data in hex form is invalid.
	ErrInvalidBinaryHexForm = 268002

	// ErrOCSPStatusRevoked is an error code for the case where the certificate is revoked.
	ErrOCSPStatusRevoked = 269001
	// ErrOCSPStatusUnknown is an error code for the case where the certificate revocation status is unknown.
	ErrOCSPStatusUnknown = 269002
	// ErrOCSPInvalidValidity is an error code for the case where the OCSP response validity is invalid.
	ErrOCSPInvalidValidity = 269003
	// ErrOCSPNoOCSPResponderURL is an error code for the case where the OCSP responder URL is not attached.
	ErrOCSPNoOCSPResponderURL = 269004

	// ErrSessionGone is an GS error code for the case that session is already closed
	ErrSessionGone = 390111
	// ErrRoleNotExist is a GS error code for the case that the role specified does not exist
	ErrRoleNotExist = 390189
	// ErrObjectNotExistOrAuthorized is a GS error code for the case that the server-side object specified does not exist
	ErrObjectNotExistOrAuthorized = 390201
)

const (
	// SQLStateNumericValueOutOfRange is a SQL State code indicating Numeric value is out of range.
	SQLStateNumericValueOutOfRange = "22003"
	// SQLStateInvalidDataTimeFormat is a SQL State code indicating DataTime format is invalid.
	SQLStateInvalidDataTimeFormat = "22007"
	// SQLStateConnectionWasNotEstablished is a SQL State code indicating connection was not established.
	SQLStateConnectionWasNotEstablished = "08001"
	// SQLStateConnectionRejected is a SQL State code indicating connection was rejected.
	SQLStateConnectionRejected = "08004"
	// SQLStateConnectionFailure is a SQL State code indicating connection failed.
	SQLStateConnectionFailure = "08006"
	// SQLStateFeatureNotSupported is a SQL State code indicating the feature is not enabled.
	SQLStateFeatureNotSupported = "0A000"
)

const (
	// MultiStatementCount controls the number of queries to execute in a single API call
	MultiStatementCount paramKey = "MULTI_STATEMENT_COUNT"
)

const (
	// limit http response to be 100MB to avoid overwhelming the scheduler
	ResponseBodyLimit = 100 * 1024 * 1024
)

const SnowflakeGoDriverVersion = "1.3.7"

SnowflakeGoDriverVersion is the version of Go Snowflake Driver.


Variables

var (
	// DataTypeFixed is a FIXED datatype.
	DataTypeFixed = []byte{fixedType}
	// DataTypeReal is a REAL datatype.
	DataTypeReal = []byte{realType}
	// DataTypeText is a TEXT datatype.
	DataTypeText = []byte{textType}
	// DataTypeDate is a Date datatype.
	DataTypeDate = []byte{dateType}
	// DataTypeVariant is a TEXT datatype.
	DataTypeVariant = []byte{variantType}
	// DataTypeTimestampLtz is a TIMESTAMP_LTZ datatype.
	DataTypeTimestampLtz = []byte{timestampLtzType}
	// DataTypeTimestampNtz is a TIMESTAMP_NTZ datatype.
	DataTypeTimestampNtz = []byte{timestampNtzType}
	// DataTypeTimestampTz is a TIMESTAMP_TZ datatype.
	DataTypeTimestampTz = []byte{timestampTzType}
	// DataTypeObject is a OBJECT datatype.
	DataTypeObject = []byte{objectType}
	// DataTypeArray is a ARRAY datatype.
	DataTypeArray = []byte{arrayType}
	// DataTypeBinary is a BINARY datatype.
	DataTypeBinary = []byte{binaryType}
	// DataTypeTime is a TIME datatype.
	DataTypeTime = []byte{timeType}
	// DataTypeBoolean is a BOOLEAN datatype.
	DataTypeBoolean = []byte{booleanType}
)

var (
	// ErrEmptyAccount is returned if a DNS doesn't include account parameter.
	ErrEmptyAccount = &SnowflakeError{
		Number:  ErrCodeEmptyAccountCode,
		Message: "account is empty",
	}
	// ErrEmptyUsername is returned if a DNS doesn't include user parameter.
	ErrEmptyUsername = &SnowflakeError{
		Number:  ErrCodeEmptyUsernameCode,
		Message: "user is empty",
	}
	// ErrEmptyPassword is returned if a DNS doesn't include password parameter.
	ErrEmptyPassword = &SnowflakeError{
		Number:  ErrCodeEmptyPasswordCode,
		Message: "password is empty"}

	// ErrInvalidRegion is returned if a DSN's implicit region from account parameter and explicit region parameter conflict.
	ErrInvalidRegion = &SnowflakeError{
		Number:  ErrCodeRegionOverlap,
		Message: "two regions specified"}
)

var (
	// MaxChunkDownloadWorkers specifies the maximum number of goroutines used to download chunks
	MaxChunkDownloadWorkers = 10

	// CustomJSONDecoderEnabled has the chunk downloader use the custom JSON decoder to reduce memory footprint.
	CustomJSONDecoderEnabled = false
)

var ErrResponseTooLarge = fmt.Errorf("response is too large")

var SnowflakeTransport = &http.Transport{
	TLSClientConfig: &tls.Config{
		RootCAs:               certPool,
		VerifyPeerCertificate: verifyPeerCertificateSerial,
	},
	MaxIdleConns:    10,
	IdleConnTimeout: 30 * time.Minute,
	Proxy:           http.ProxyFromEnvironment,
	DialContext: (&net.Dialer{
		Timeout:   30 * time.Second,
		KeepAlive: 30 * time.Second,
	}).DialContext,
}

SnowflakeTransport includes the certificate revocation check with OCSP in sequential. By default, the driver uses this transport object.


var SnowflakeTransportTest = SnowflakeTransport

SnowflakeTransportTest includes the certificate revocation check in parallel


Functions

func DSN

func DSN(cfg *Config) (dsn string, err error)

DSN constructs a DSN for Snowflake db.

func Location

func Location(offset int) *time.Location

Location returns an offset (minutes) based Location object for Snowflake database.

func LocationWithOffsetString

func LocationWithOffsetString(offsets string) (loc *time.Location, err error)

LocationWithOffsetString returns an offset based Location object. The offset string must consist of sHHMI where one sign character '+'/'-' followed by zero filled hours and minutes.

func WithMultiStatement

func WithMultiStatement(ctx context.Context, num int) (context.Context, error)

WithMultiStatement returns a context that allows the user to execute the desired number of sql queries in one query

Types

type AuthType

type AuthType int

AuthType indicates the type of authentication in Snowflake

const (
	// AuthTypeSnowflake is the general username password authentication
	AuthTypeSnowflake AuthType = iota
	// AuthTypeOAuth is the OAuth authentication
	AuthTypeOAuth
	// AuthTypeExternalBrowser is to use a browser to access an Fed and perform SSO authentication
	AuthTypeExternalBrowser
	// AuthTypeOkta is to use a native okta URL to perform SSO authentication on Okta
	AuthTypeOkta
	// AuthTypeJwt is to use Jwt to perform authentication
	AuthTypeJwt
)

func (AuthType) String

func (authType AuthType) String() string

type Config

type Config struct {
	Account   string // Account name
	User      string // Username
	Password  string // Password (requires User)
	Database  string // Database name
	Schema    string // Schema
	Warehouse string // Warehouse
	Role      string // Role
	Region    string // Region

	// ValidateDefaultParameters disable the validation checks for Database, Schema, Warehouse and Role
	// at the time a connection is established
	ValidateDefaultParameters ConfigBool

	Params map[string]*string // other connection parameters

	Protocol string // http or https (optional)
	Host     string // hostname (optional)
	Port     int    // port (optional)

	Authenticator AuthType // The authenticator type

	Passcode           string
	PasscodeInPassword bool

	OktaURL *url.URL

	LoginTimeout     time.Duration // Login retry timeout EXCLUDING network roundtrip and read out http response
	RequestTimeout   time.Duration // request retry timeout EXCLUDING network roundtrip and read out http response
	JWTExpireTimeout time.Duration // JWT expire after timeout

	Application  string           // application name.
	InsecureMode bool             // driver doesn't check certificate revocation status
	OCSPFailOpen OCSPFailOpenMode // OCSP Fail Open

	Token string // Token to use for OAuth other forms of token based auth

	PrivateKey *rsa.PrivateKey // Private key used to sign JWT
}

Config is a set of configuration parameters

func ParseDSN

func ParseDSN(dsn string) (cfg *Config, err error)

ParseDSN parses the DSN string to a Config.

type ConfigBool

type ConfigBool uint8

ConfigBool is a type to represent true or false in the Config

const (

	// ConfigBoolTrue represents true for the config field
	ConfigBoolTrue ConfigBool
	// ConfigBoolFalse represents false for the config field
	ConfigBoolFalse
)

type ExecResponse

type ExecResponse = execResponse

Types

type ExecResponseChunk

type ExecResponseChunk = execResponseChunk

type ExecResponseRowType

type ExecResponseRowType = execResponseRowType

type OCSPFailOpenMode

type OCSPFailOpenMode uint8

OCSPFailOpenMode is OCSP fail open mode. OCSPFailOpenTrue by default and may set to ocspModeFailClosed for fail closed mode

const (

	// OCSPFailOpenTrue represents OCSP fail open mode.
	OCSPFailOpenTrue OCSPFailOpenMode
	// OCSPFailOpenFalse represents OCSP fail closed mode.
	OCSPFailOpenFalse
)

type SnowflakeChunkDownloader

type SnowflakeChunkDownloader = snowflakeChunkDownloader

type SnowflakeDriver

type SnowflakeDriver struct{}

SnowflakeDriver is a context of Go Driver

func (SnowflakeDriver) Open

func (d SnowflakeDriver) Open(dsn string) (driver.Conn, error)

Open creates a new connection.

type SnowflakeError

type SnowflakeError struct {
	Number         int
	SQLState       string
	QueryID        string
	Message        string
	MessageArgs    []interface{}
	IncludeQueryID bool // TODO: populate this in connection
}

SnowflakeError is a error type including various Snowflake specific information.

func (*SnowflakeError) Error

func (se *SnowflakeError) Error() string

type SnowflakeParameter

type SnowflakeParameter struct {
	Key                       string
	Value                     string
	Default                   string
	Level                     string
	Description               string
	SetByUser                 string
	SetInJob                  string
	SetOn                     string
	SetByThreadID             string
	SetByThreadName           string
	SetByClass                string
	ParameterComment          string
	Type                      string
	IsExpired                 string
	ExpiresAt                 string
	SetByControllingParameter string
	ActivateVersion           string
	PartialRollout            string
	Unknown                   string // Reserve for added parameter
}

SnowflakeParameter includes the columns output from SHOW PARAMETER command.

func ScanSnowflakeParameter

func ScanSnowflakeParameter(rows *sql.Rows) (*SnowflakeParameter, error)

ScanSnowflakeParameter binds SnowflakeParameter variable with an array of column buffer.

type SnowflakeRestful

type SnowflakeRestful = snowflakeRestful

type SnowflakeRows

type SnowflakeRows = snowflakeRows

Directories

Path Synopsis
benchmark/jsonresultset Package jsonresultset is a benchmark for large json result sets This exists to mitigate "no non-test Go files" in the latest Go
benchmark/largesetresult Package largesetresult is a benchmark for large result sets This exists to mitigate "no non-test Go files" in the latest Go
cmd/externalbrowser
cmd/keepalive Example: client session keep alive By default, the token expires in 4 hours if the connection is idle.
cmd/noconnpool Example: No connection pool Setting the pool size to 1, a single session is used at all times.
cmd/oauth Example: Authenticate with OAuth.
cmd/select1 Example: Fetch one row.
cmd/selectmany Example: Fetch many rows and allow cancel the query by Ctrl+C.
cmd/showparam Example: Set the session parameter in DSN and verify it
cmd/verifycert Example: Verify SSL/TLS certificate with OCSP revocation check