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

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.

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:

The Postgres, Yugabyte, and Cockroach engines use the "PGUSER" environment variable, if set. Otherwise, it uses the system username.
For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files <https://dev.mysql.com/doc/refman/5.7/en/password-security-user.html>. 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 provides no default to search for a username.
The Vertica engine uses the "VSQL_USER" environment variable, if set. Otherwise, it uses the system username.
The Firebird engine uses the "ISC_USER" environment variable, if set.
Exasol provides no default to search for a username.
The Snowflake engine uses the "SNOWSQL_USER" environment variable, if set. Next, it looks in the ~/.snowsql/config file <https://docs.snowflake.com/en/user-guide/snowsql-start.html#snowsql-config-file> and use the default "connections.username" value. Otherwise, it uses the system username.

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.

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 supports a number of authentication methods <https://www.postgresql.org/docs/current/static/auth-methods.html>, including the passwordless SSL certificate <https://www.postgresql.org/docs/current/static/auth-methods.html#AUTH-CERT>, GSSAPI <https://www.postgresql.org/docs/current/static/auth-methods.html#GSSAPI-AUTH>, and, for local connections, peer authentication <https://www.postgresql.org/docs/current/static/auth-methods.html#AUTH-PEER>.
MySQL supports a number of authentication methods <https://dev.mysql.com/doc/internals/en/authentication-method.html>, plus SSL authentication <https://dev.mysql.com/doc/internals/en/ssl.html>.
Oracle supports a number of authentication methods <https://docs.oracle.com/cd/B19306_01/network.102/b14266/authmeth.htm#BABCGGEB>, including SSL authentication <https://docs.oracle.com/cd/B19306_01/network.102/b14266/authmeth.htm#i1009722>, third-party authentication <https://docs.oracle.com/cd/B19306_01/network.102/b14266/authmeth.htm#i1009853>, and, for local connections, OS authentication <https://docs.oracle.com/cd/B19306_01/network.102/b14266/authmeth.htm#i1007520>.
Vertica supports a number of authentication methods <https://my.vertica.com/docs/7.1.x/HTML/index.htm#Authoring/AdministratorsGuide/Security/ClientAuth/SupportedClientAuthenticationMethods.htm> including the passwordless TLS authentication <https://my.vertica.com/docs/7.1.x/HTML/index.htm#Authoring/AdministratorsGuide/Security/ClientAuth/ConfiguringTLSAuthentication.htm>, GSS authentication <https://my.vertica.com/docs/7.1.x/HTML/index.htm#Authoring/AdministratorsGuide/Security/ClientAuth/Kerberos/ImplementingKerberosAuthentication.htm>, and, for local connections, ident authentication <https://my.vertica.com/docs/7.1.x/HTML/index.htm#Authoring/AdministratorsGuide/Security/ClientAuth/ConfiguringIdentAuthentication.htm>.
Firebird supports passwordless authentication only via trusted authentication <https://www.firebirdsql.org/manual/qsg2-config.html> for local connections.
Exasol doesn't seem to support password-less authentication at this time, though there is support for Authentication using OpenID <https://docs.exasol.com/sql/create_user.htm#Authenti4>. 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 does not support password-less authentication, but does support key-pair authentication. Follow the instructions <https://docs.snowflake.com/en/user-guide/snowsql-start.html#using-key-pair-authentication> to create a key pair, then set the following variables in the ~/.snowsql/config file: 

  authenticator = SNOWFLAKE_JWT
  private_key_path = "path/to/privatekey.p8"

To connect, set the $SNOWSQL_PRIVATE_KEY_PASSPHRASE environment variable to the passphrase for the private key, and add these parameters to the query part of your connection URI:

  • "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

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, and CockroachDB will use a .pgpass file <https://www.postgresql.org/docs/current/static/libpq-pgpass.html> 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
For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files <https://dev.mysql.com/doc/refman/5.7/en/password-security-user.html>. 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 supports password file <https://docs.oracle.com/cd/B28359_01/server.111/b28310/dba007.htm#ADMIN10241> 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 <https://stackoverflow.com/q/7183513/79202> into a tnsnames.ora <https://docs.oracle.com/cd/B28359_01/network.111/b28317/tnsnames.htm#NETRF007> file.
Vertica does not currently support a password file.
Firebird does not currently support a password file.
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 <https://www.exasol.com/portal/display/DOC/Database+User+Manual> 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
For Snowflake, Sqitch will read the ~/.snowsql/config file <https://docs.snowflake.com/en/user-guide/snowsql-start.html#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"

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:

$PGPASSWORD
$MYSQL_PWD
$VSQL_PASSWORD
$ISC_PASSWORD
$SNOWSQL_PWD

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.

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

Part of the sqitch suite.

2022-10-15 perl v5.34.0