Login Credentials

The /wiki/spaces/SD/pages/242942034 is a command line tool for issuing SciDB queries. When SciDB is running in security mode, iquery must present login credentials (that is, username and password) in order to establish a database connection. You specify login credentials using an authentication file. If iquery cannot find an authentication file, or if it finds an authentication file containing a user-name entry but no user-password entry, it prompts you for a password on the terminal.

Legal Usernames

A valid username must meet these criteria:

Cannot be empty.
Cannot exceed 256 bytes in length.
Must not contain whitespace.
Must not contain control characters.
Must not begin with a decimal digit.
May contain hyphens (-, ASCII 0x2D) and underscores (_, ASCII 0x5F), but not at the beginning or end of the name. No other punctuation is allowed.
Must contain only 7-bit ASCII characters.

These same rules also apply to role names.

Legal Passwords

A valid password must meet these criteria:

Cannot be empty.
Cannot exceed 256 bytes in length.
Must not contain control characters.
Must contain only 7-bit ASCII characters.

For INI format authentication files, there are further limitations:

Cannot have leading or trailing whitespace.
Must not contain single quote (ASCII 0x2C) or backslashes (ASCII 0x5C).

Authentication File Format

SciDB authentication files may be in either of two formats: JSON or INI. JSON is the preferred format. The iquery program first tries to parse an authentication file as JSON, and if that fails, it tries to parse it as INI.

Both formats are case-sensitive.

Because authentication files contain cleartext passwords, iquery will refuse to use an authentication file unless its file protection mode is either 0600 (read and write permission for owner and for no one else) or 0400 (read permission for owner and no one else). See the Linux chmod(1) manual page.

JSON authentication files

Here is a sample JSON authentication file containing the factory default credentials for the scidbadmin user:

{
  "user-name": "scidbadmin",
  "user-password": "Paradigm4"
}

If your password contains characters that would cause a JSON parse error, you must escape them with backslashes.

INI authentication files

For compatibility with prior releases, iquery supports the INI authentication file format.

Here is an INI format authentication file containing the factory default credentials for the scidbadmin user:

[security_password]
user-name=scidbadmin
user-password=Paradigm4

Limitations of INI authentication files

The INI format does not support quoted option values, so passwords cannot have leading or trailing space characters. Earlier SciDB versions also imposed additional restrictions on allowable password characters. The only allowable characters were:

alphanumeric characters
comma, ASCII 0x2C
period, ASCII 0x2E
forward slash, ASCII 0x2F
hyphen, ASCII 0x2D
underscore, ASCII 0x5F

If you use INI format authentication files, limit passwords to this character set to avoid complications.

How iquery Locates Authentication Files

The iquery program first looks for its authentication file on the command line, then tries to get it from an environment variable, and finally looks for it in a default location in your home directory.

Command line option: -A/--auth-file

You can specify a particular authentication file directly on the iquery command line using the -A/--auth-file command line option. For example:

$ cat /tmp/alice.auth
{ "user-name": "alice", "user-password": "big secret" }
$ iquery -A /tmp/alice.auth -aq "show_user()"
{i} name
{0} 'alice'
$

Environment variable: SCIDB_CONFIG_USER

If no command line option is given, iquery next examines the value of the SCIDB_CONFIG_USER environment variable and uses its value as the name of the authentication file:

$ export SCIDB_CONFIG_USER=/tmp/alice.auth
$ iquery -aq "show_user()"
{i} name
{0} 'alice'
$

Default location: $HOME/.config/scidb/iquery.auth

If no explicit command line option is given and the SCIDB_CONFIG_USER environment variable is not set, iquery tries to use $HOME/.config/scidb/iquery.auth as the authentication file:

$ unset SCIDB_CONFIG_USER
$ cp /tmp/alice.auth ~/.config/scidb/iquery.auth
$ iquery -aq "show_user()"
{i} name
{0} 'alice'
$

Entering Passwords Via The Terminal

If iquery needs a password to connect to SciDB and none can be found in an authentication file, it prompts for a password on the terminal using getpass(3).

If iquery found an authentication file with only a user-name entry but no user-password entry, it uses that user name when connecting to the database. Otherwise, if it finds no authentication file, it uses the name of the logged in user, taken from the $USER environment variable.

You have a limited time to respond to the password prompt before SciDB closes iquery's TCP connection. The timeout is given by the SciDB client-auth-timeout configuration parameter.

About iquery Examples In The Security Documentation

Specifying the -A/--auth-file iquery command line option in every example quickly becomes tedious and distracts from the teaching value of the example. The examples in the Security section assume that a proper $HOME/.config/scidb/iquery.auth authentication file is already set up, and forego mention of it unless it is directly relevant to the point of the example.

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