spanner-cli

spanner-cli

Interactive command line tool for Cloud Spanner.

Description

spanner-cli is an interactive command line tool for Google Cloud Spanner.
You can control your Spanner databases with idiomatic SQL commands.

Install

Install Go and run the following command.

# For Go 1.16+
go install github.com/cloudspannerecosystem/spanner-cli@latest

# For Go <1.16
go get -u github.com/cloudspannerecosystem/spanner-cli

Or you can download the old binary from the releases.

Usage

Usage:
  spanner-cli [OPTIONS]

spanner:
  -p, --project=       (required) GCP Project ID. [$SPANNER_PROJECT_ID]
  -i, --instance=      (required) Cloud Spanner Instance ID [$SPANNER_INSTANCE_ID]
  -d, --database=      (required) Cloud Spanner Database ID. [$SPANNER_DATABASE_ID]
  -e, --execute=       Execute SQL statement and quit.
  -f, --file=          Execute SQL statement from file and quit.
  -t, --table          Display output in table format for batch mode.
  -v, --verbose        Display verbose output.
      --credential=    Use the specific credential file
      --prompt=        Set the prompt to the specified format
      --history=       Set the history file to the specified path
      --priority=      Set default request priority (HIGH|MEDIUM|LOW)
      --role=          Use the specific database role
      --directed-read= Directed read option (replica_location:replica_type).
                       The replicat_type is optional and either READ_ONLY or READ_WRITE.

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

Unless you specify a credential file with --credential, this tool uses Application Default Credentials as credential source to connect to Spanner databases.
Please make sure to prepare your credential by gcloud auth application-default login.

Example

Interactive mode

$ spanner-cli -p myproject -i myinstance -d mydb
Connected.
spanner> CREATE TABLE users (
      ->   id INT64 NOT NULL,
      ->   name STRING(16) NOT NULL,
      ->   active BOOL NOT NULL
      -> ) PRIMARY KEY (id);
Query OK, 0 rows affected (30.60 sec)

spanner> SHOW TABLES;
+----------------+
| Tables_in_mydb |
+----------------+
| users          |
+----------------+
1 rows in set (18.66 msecs)

spanner> INSERT INTO users (id, name, active) VALUES (1, "foo", true), (2, "bar", false);
Query OK, 2 rows affected (5.08 sec)

spanner> SELECT * FROM users ORDER BY id ASC;
+----+------+--------+
| id | name | active |
+----+------+--------+
| 1  | foo  | true   |
| 2  | bar  | false  |
+----+------+--------+
2 rows in set (3.09 msecs)

spanner> BEGIN;
Query OK, 0 rows affected (0.02 sec)

spanner(rw txn)> DELETE FROM users WHERE active = false;
Query OK, 1 rows affected (0.61 sec)

spanner(rw txn)> COMMIT;
Query OK, 0 rows affected (0.20 sec)

spanner> SELECT * FROM users ORDER BY id ASC;
+----+------+--------+
| id | name | active |
+----+------+--------+
| 1  | foo  | true   |
+----+------+--------+
1 rows in set (2.58 msecs)

spanner> DROP TABLE users;
Query OK, 0 rows affected (25.20 sec)

spanner> SHOW TABLES;
Empty set (2.02 msecs)

spanner> EXIT;
Bye

Batch mode

By passing SQL from standard input, spanner-cli runs in batch mode.

$ echo 'SELECT * FROM users;' | spanner-cli -p myproject -i myinstance -d mydb
id      name    active
1       foo     true
2       bar     false

You can also pass SQL with command line option -e.

$ spanner-cli -p myproject -i myinstance -d mydb -e 'SELECT * FROM users;'
id      name    active
1       foo     true
2       bar     false

With -t option, results are displayed in table format.

$ spanner-cli -p myproject -i myinstance -d mydb -e 'SELECT * FROM users;' -t
+----+------+--------+
| id | name | active |
+----+------+--------+
| 1  | foo  | true   |
| 2  | bar  | false  |
+----+------+--------+

Directed reads mode

spanner-cli now supports directed reads, a feature that allows you to read data from a specific replica of a Spanner database. To use directed reads with spanner-cli, you need to specify the --directed-read flag. The --directed-read flag takes a single argument, which is the name of the replica that you want to read from. The replica name can be specified in one of the following formats:

• <replica_location>
• <replica_location>:<replica_type>

The <replica_location> specifies the region where the replica is located such as us-central1, asia-northeast2.
The <replica_type> specifies the type of the replica either READ_WRITE or READ_ONLY.

$ spanner-cli -p myproject -i myinstance -d mydb --directed-read us-central1

$ spanner-cli -p myproject -i myinstance -d mydb --directed-read us-central1:READ_ONLY

$ spanner-cli -p myproject -i myinstance -d mydb --directed-read asia-northeast2:READ_WRITE

Directed reads are only effective for single queries or queries within a read-only transaction. Please note that directed read options do not apply to queries within a read-write transaction.

[!NOTE] If you specify an incorrect region or type for directed reads, directed reads will not be enabled and your requsts won't be routed as expected. For example, in a multi-region configuration nam3, if you mistype us-east1 as us-east-1, the connection will succeed, but directed reads will not be enabled.

To perform directed reads to asia-northeast2 in a multi-region configuration asia1, you need to specify asia-northeast2 or asia-northeast2:READ_WRITE. Since the replicas placed in asia-northeast2 are READ_WRITE replicas, directed reads will not be enabled if you specify asia-northeast2:READ_ONLY.

Please refer to the Spanner documentation to verify the valid configurations.

Syntax

In the following syntax, we use <> for a placeholder, [] for an optional keyword, and {} for a mutually exclusive keyword.

• The syntax is case-insensitive.
• \G delimiter is also supported for displaying results vertically.

Customize prompt

You can customize the prompt by --prompt option.
There are some defined variables for being used in prompt.

Variables:

• \p : GCP Project ID
• \i : Cloud Spanner Instance ID
• \d : Cloud Spanner Database ID
• \t : In transaction

Example:

$ spanner-cli -p myproject -i myinstance -d mydb --prompt='[\p:\i:\d]\t> '
Connected.
[myproject:myinstance:mydb]> SELECT * FROM users ORDER BY id ASC;
+----+------+--------+
| id | name | active |
+----+------+--------+
| 1  | foo  | true   |
| 2  | bar  | false  |
+----+------+--------+
2 rows in set (3.09 msecs)

[myproject:myinstance:mydb]> begin;
Query OK, 0 rows affected (0.08 sec)

[myproject:myinstance:mydb](rw txn)> ...

The default prompt is spanner\t> .

Config file

This tool supports a configuration file called spanner_cli.cnf, similar to my.cnf.
The config file path must be ~/.spanner_cli.cnf.
In the config file, you can set default option values for command line options.

Example:

[spanner]
project = myproject
instance = myinstance
prompt = "[\\p:\\i:\\d]\\t> "

Configuration Precedence

1. Command line flags(highest)
2. Environment variables
3. .spanner_cli.cnf in current directory
4. .spanner_cli.cnf in home directory(lowest)

Request Priority

You can set request priority for command level or transaction level. By default MEDIUM priority is used for every request.

To set a priority for command line level, you can use --priority={HIGH|MEDIUM|LOW} command line option.

To set a priority for transaction level, you can use PRIORITY {HIGH|MEDIUM|LOW} keyword.

Here are some examples for transaction-level priority.

# Read-write transaction with low priority
BEGIN PRIORITY LOW;

# Read-only transaction with low priority
BEGIN RO PRIORITY LOW;

# Read-only transaction with 60s stale read and medium priority
BEGIN RO 60 PRIORITY MEDIUM;

# Read-only transaction with exact timestamp and medium priority
BEGIN RO 2021-04-01T23:47:44+00:00 PRIORITY MEDIUM;

Note that transaction-level priority takes precedence over command-level priority.

Transaction Tags and Request Tags

In a read-write transaction, you can add a tag following BEGIN RW TAG <tag>. spanner-cli adds the tag set in BEGIN RW TAG as a transaction tag. The tag will also be used as request tags within the transaction.

# Read-write transaction
# transaction_tag = tx1
+--------------------+
| BEGIN RW TAG tx1;  |
|                    |
| SELECT val         |
| FROM tab1      +-----request_tag = tx1
| WHERE id = 1;      |
|                    |
| UPDATE tab1        |
| SET val = 10   +-----request_tag = tx1
| WHERE id = 1;      |
|                    |
| COMMIT;            |
+--------------------+

In a read-only transaction, you can add a tag following BEGIN RO TAG <tag>. Since read-only transaction doesn't support transaction tag, spanner-cli adds the tag set in BEGIN RO TAG as request tags.

# Read-only transaction
# transaction_tag = N/A
+--------------------+
| BEGIN RO TAG tx2;  |
|                    |
| SELECT SUM(val)    |
| FROM tab1      +-----request_tag = tx2
| WHERE id = 1;      |
|                    |
| CLOSE;             |
+--------------------+

Using with the Cloud Spanner Emulator

This tool supports the Cloud Spanner Emulator via the SPANNER_EMULATOR_HOST environment variable.

$ export SPANNER_EMULATOR_HOST=localhost:9010
# Or with gcloud env-init:
$ $(gcloud emulators spanner env-init)

$ spanner-cli -p myproject -i myinstance -d mydb

How to develop

Run unit tests.

$ make test

Run integration tests, which connects to real Cloud Spanner database.

$ PROJECT=${PROJECT_ID} INSTANCE=${INSTANCE_ID} DATABASE=${DATABASE_ID} CREDENTIAL=${CREDENTIAL} make test

TODO

• Show secondary index by "SHOW CREATE TABLE"

Disclaimer

Do not use this tool for production databases as the tool is still alpha quality.

Please feel free to report issues and send pull requests, but note that this application is not officially supported as part of the Cloud Spanner product.