Name

sqitch-authentication - Guide to using database authentication credentials with Sqitch

Description

For database engines that require authentication, Sqitch supports a number of credential-specification options, and searches for them in a specific sequence. These searches are performed in two parts: a search for a username and a search for a password.

Usernames

Sqitch searches for usernames sequentially, using the first value it finds. Any of these approaches may be used to specify a username, in this order:

• 1. In the $SQITCH_USERNAME environment variable
• 2. Via the --db-username option
• 3. In the deploy target URI; this is the preferred option
• 4. In an engine-specific environment variable or configuration

Naturally, this last option varies by database engine. The details are as follows:

• PostgreSQL, YugabyteDB, CockroachDB

  The Postgres, Yugabyte, and Cockroach engines use the PGUSER environment variable, if set. Otherwise, it uses the system username.

• MySQL

  For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files. These files must limit access only to the current user (0600). Sqitch will look for a username and password under the [client] and [mysql] sections, in that order.

• Oracle

  Oracle provides no default to search for a username.

• Vertica

  The Vertica engine uses the VSQL_USER environment variable, if set. Otherwise, it uses the system username.

• Firebird

  The Firebird engine uses the ISC_USER environment variable, if set.

• Exasol

  Exasol provides no default to search for a username.

• Snowflake

  The Snowflake engine uses the SNOWSQL_USER environment variable, if set. Next, it looks in the ~/.snowsql/config file and use the default connections.username value. Otherwise, it uses the system username.

• ClickHouse

  The ClickHouse engine uses the CLICKHOUSE_USER environment variable, if set.

Passwords

You may have noticed that Sqitch has no --password option. This is intentional. It’s generally not a great idea to specify a password on the command-line: from there, it gets logged to your command history and is easy to extract by anyone with access to your system. So you might wonder how to specify passwords so that Sqitch an successfully deploy to databases that require passwords. There are four approaches, in order from most- to least-recommended:

• 1. Avoid using a password at all
• 2. Use a database engine-specific password file
• 3. Use the $SQITCH_PASSWORD environment variable
• 4. Include the password in the deploy target URI

Each is covered in detail in the sections below.

Don’t use Passwords

Of course, the best way to protect your passwords is not to use them at all. If your database engine is able to do passwordless authentication, it’s worth taking the time to make it work, especially on your production database systems. Some examples:

• PostgreSQL

  PostgreSQL supports a number of authentication methods, including the passwordless SSL certificate, GSSAPI, and, for local connections, peer authentication.

• MySQL

  MySQL supports a number of authentication methods, plus SSL authentication.

• Oracle

  Oracle supports a number of authentication methods, including SSL authentication, third-party authentication, and, for local connections, OS authentication.

• Vertica

  Vertica supports a number of authentication methods including the passwordless TLS authentication, GSS authentication, and, for local connections, ident authentication.

• Firebird

  Firebird supports passwordless authentication only via trusted authentication for local connections.

• Exasol

  Exasol doesn’t seem to support password-less authentication at this time, though there is support for Authentication using OpenID. To use it with Sqitch, include AUTHMETHOD=refreshtoken in the target URI query string, e.g.,

  db:exasol://sys:exasol@localhost:8563/?Driver=Exasol&AUTHMETHOD=refreshtoken
  

• Snowflake

  Snowflake does not support password-less authentication, but does support key-pair authentication. Follow the instructions to create a key pair, then set the private_key_path in the ~/.snowsql/config to point to the private key file:

  private_key_path = "<path>/rsa_key.p8"
  

  To connect, set the $SNOWSQL_PRIVATE_KEY_PASSPHRASE environment variable to the passphrase for the private key, and add these parameters under the configuration for your DSN in /etc/odbc.ini or ~/.odbc.ini:

  [sqitch]
  AUTHENTICATOR     = SNOWFLAKE_JWT
  UID               = <username>
  PRIV_KEY_FILE     = <path>/rsa_key.p8
  PRIV_KEY_FILE_PWD = <password>
  

  Then connect using the named DSN via the DSN query parameter:

  db:snowflake://movera@example.snowflakecomputing.com/flipr?warehouse=compute_wh;DSN=sqitch
  

  Or add the ODBC parameters directly to the query part of your connection URI (although it’s safer to put priv_key_file_pwd in odbc.ini):

  • authenticator=SNOWFLAKE_JWT
  • uid=$username
  • priv_key_file=path/to/privatekey.p8
  • priv_key_file_pwd=$private_key_password

  For example:

  db:snowflake://movera@example.snowflakecomputing.com/flipr?Driver=Snowflake;warehouse=sqitch;authenticator=SNOWFLAKE_JWT;uid=movera;priv_key_file=path/to/privatekey.p8;priv_key_file_pwd=s0up3rs3cre7
  

  Sadly, both the SNOWSQL_PRIVATE_KEY_PASSPHRASE environment variable and the priv_key_file_pwd ODBC parameter must be set, as Sqitch uses ODBC to maintain its registry and SnowSQL to execute change scripts.

• ClickHouse

  ClickHouse does not support password-less authentication, but does support TLS Client authentication. Sqitch reads the $.openSSL.client section of the Client configuration|https://clickhouse.com/docs/interfaces/cli#connection-credentials to also configure is ODBC connection. For example, given this config:

  <config>
   <openSSL>
     <client>
       <certificateFile>my_cert_name.crt</certificateFile>
       <privateKeyFile>my_cert_name.key</privateKeyFile>
     </client>
   </openSSL>
    </config>
  

  It maps the configuration parameters to the ODBC parameters https://github.com/clickHouse/clickhouse-odbc?tab=readme-ov-file#configuration as follows:

  • privateKeyFile: PrivateKeyFile

    Path to private key file. Raises an error if both are set and not the same value.

  • certificateFile: CertificateFile

    Path to certificate file. Raises an error if both are set and not the same value.

  • caConfig: CALocation

    Path to the file or directory containing the CA/root certificates. Raises an error if both are set and not the same value.

  • secure, port, host, verificationMode: SSLMode

    Sets the ODBC SSLMode parameter to require when the secure parameter from the configuration file is true or the port is 9440, or the host name from the configuration file or the target ends in .clickhouse.cloud. If none of those are true but verificationMode is set, set the SSLMode query parameters as follows:

    verificationMode | SSLMode
      ------------------|-----------
    none             | [not set]
    relaxed          | allow
    strict           | require
    once             | require
    

  Unfortunately, these parameters cannot currently be specified exclusively via ODBC parameters, because the client lacks options or environment variables to match. It’s best for now to omit them from target URIs and rely only on the client configuration.

Use a Password File

If you must use password authentication with your database server, you may be able to use a protected password file. This is file with access limited only to the current user that the server client library can read in. As such, the format is specified by the database vendor, and not all database servers offer the feature. Here’s how the database engines supported by Sqitch shake out:

• PostgreSQL, YugabyteDB, CockroachDB

  PostgreSQL, YugabyteDB, and CockroachDB will use a .pgpass file in the user’s home directory to or referenced by the $PGPASSFILE environment variable. This file must limit access only to the current user (0600) and contains lines specify authentication rules as follows:

  hostname:port:database:username:password
  

• MySQL

  For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files. These files must limit access only to the current user (0600). Sqitch will look for a username and password under the [client] and [mysql] sections, in that order.

• Oracle

  Oracle supports password file created with the ORAPWD utility to authenticate SYSDBA and SYSOPER users, but Sqitch is unable to take advantage of this functionality. Neither can one embed a username and password into a tnsnames.ora file.

• Vertica

  Vertica does not currently support a password file.

• Firebird

  Firebird does not currently support a password file.

• Exasol

  Exasol allows configuring connection profiles for the ’exaplus’ client:

  > exaplus -u sys -p exasol -c localhost:8563 -wp flipr_test
  EXAplus 6.0.4 (c) EXASOL AG
  
  Profile flipr_test is saved.
  > exaplus -profile flipr_test -q -sql "select current_timestamp;"
  
  CURRENT_TIMESTAMP
  --------------------------
  2017-11-02 13:35:48.360000
  

  These profiles are stored in ~/.exasol/profiles.xml, readable only to the user by default. See the documentation for more information on connection profiles, specifically the EXAplus section in the chapter on “Clients and interfaces”.

  For ODBC connections from Sqitch, we can use connection settings in ~/.odbc.ini:

  [flipr_test]
  DRIVER = Exasol
  EXAHOST = localhost:8563
  EXAUID = sys
  EXAPWD = exasol
  AUTHMETHOD = refreshtoken
  

  When combining the above, Sqitch doesn’t need to know any credentials; they are stored somewhat safely in ~/.exasol/profiles.xml and ~/.odbc.ini:

  > sqitch status db:exasol:flipr_test
  # On database db:exasol:flipr_test
  # Project:  flipr
  # ...
  #
  Nothing to deploy (up-to-date)
  > sqitch rebase --onto '@HEAD^' -y db:exasol:flipr_test
  Reverting changes to hashtags @v1.0.0-dev2 from db:exasol:flipr_test
    - userflips .. ok
  Deploying changes to db:exasol:flipr_test
    + userflips .. ok
  

• Snowflake

  For Snowflake, Sqitch will read the ~/.snowsql/config file and use the default connections settings; named connections are not supported. An example:

  [connections]
  accountname = myaccount.us-east-1
  warehousename = compute
  username = frank
  password = fistula postmark bag
  rolename = ACCOUNTADMIN
  dbname = reporting
  

  The variables that Sqitch currently reads are:

  • connections.accountname
  • connections.username
  • connections.password
  • connections.rolename
  • connections.region (Deprecated by Snowflake)
  • connections.warehousename
  • connections.dbname

• ClickHouse

  ClickHouse supports password configuration via its client configuration file. Sqitch will read the host, port, database, and password parameters from either the root of the configuration file, as well as the secure and openSSL.client parameters, for example:

  <config>
    <user>username</user>
    <password>password</password>
    <secure>true</secure>
    <openSSL>
      <client>
        <caConfig>/etc/ssl/cert.pem</caConfig>
      </client>
    </openSSL>
  </config>
  

  All but the openSSL.client parameters may be set on a named connection basis, matched by the host name in the target URL (or the $CLICKHOUSE_HOSTNAME environment variable). All the parameters are the same except host becomes hostname. For example, to set parameters for the host click.house:

  <config>
    <connections_credentials>
      <connection>
        <name>click.house</name>
        <hostname>clickhouse.example.com</hostname>
        <port>9440</port>
        <secure>1</secure>
        <user>default</user>
        <password>password</password>
      </connection>
    </connections_credentials>
  </config>
  

  Note that setting port to 9440 will implicitly set the ODBC port to 8443 unless it’s explicitly set to something else.

Use $SQITCH_PASSWORD

The $SQITCH_PASSWORD environment variable can be used to specify the password for any supported database engine. However use of this environment variable is not recommended for security reasons, as some operating systems allow non-root users to see process environment variables via ps.

The behavior of $SQITCH_PASSWORD is consistent across all supported engines, as is the complementary $SQITCH_USERNAME environment variable. Some database engines support their own password environment variables, which you may wish to use instead. However, their behaviors may not be consistent:

• PostgreSQL, YugabyteDB, CockroachDB

  $PGPASSWORD

• MySQL

  $MYSQL_PWD

• Vertica

  $VSQL_PASSWORD

• Firebird

  $ISC_PASSWORD

• Snowflake

  $SNOWSQL_PWD

• ClickHouse

  $CLICKHOUSE_PASSWORD

Use Target URIs

Passwords may also be specified in target URIs. This is not generally recommended, since such URIs are either specified via the command-line (and therefore visible in ps and your shell history) or stored in the configuration, the project instance of which is generally pushed to your source code repository. But it’s provided here as an absolute last resort (and because web URLs support it, though it’s heavily frowned upon there, too).

Such URIs can either be specified on the command-line:

sqitch deploy db:pg://fred:s3cr3t@db.example.com/widgets

Or stored as named targets in the project configuration file:

sqitch target add wigets db:pg://fred:s3cr3t@db.example.com/widgets

After which the target is available by its name:

sqitch deploy widgets

See sqitch-targets and sqitch-configuration for details on target configuration.

See Also

• sqitch-environment
• sqitch-configuration
• sqitch-target

Sqitch

Part of the sqitch suite.