Filter Expressions

A number of CLI command accept a filter expression to select the versions to display or act on:

  • benji batch-scrub, benji batch-deep-scrub: The expression selects the versions to scrub. When no filter is specified all versions are scrubbed.

  • benji enforce: The expression selects the versions to which the retention policy is applied.

  • benji ls: The filter expression selects which versions to list. When no filter is specified all versions are listed.

  • benji metadata-export, benji metadata-backup: The expression selects the versions to export or to backup respectively.

The filter expression syntax is a subset of Python’s expression syntax. The following tokens are recognized:

  • Identifiers: These reference version metadata columns and are named date, uid, name, snapshot, size, block_size, status, protected and storage, read, written, dedup, sparse, and duration.

  • The uid identifier can either be compared to a string like uid == "V1" (leading zeros after the V are not necessary) or directly to an integer like uid == 1.

  • The status identifier should be compared to a string representing the status like status == "valid".

  • The date identifier should be compared to a string representing an absolute or relative time reference. To parse this reference dateparser with a locale of en (english) is used. The date and time format output by Benji is also accepted.

  • In addition labels can be referenced via a special dictionary named labels. The syntax is labels["label-name"]. The string literal between the square brackets can be enclosed in either single or double quotes. Labels only supported comparisons with == and !=. It is possible to test for label existence by using labels["label-name"] as a stand-alone expression.

  • Strings literals either enclosed in single or double quotes

  • Integers

  • Comparison operators: The normal set of operators is supported: ==, !=, <, >, <= and >=. Benji (actually Python and SQLAlchemy) will try to adapt types when possible.

  • Logical operators: not, and, and or (in order of precendence). not can be applied to other expressions and directly to identifiers (not protected for example, but also not labels["label-name"] to test for label absence).

  • Boolean constants: True and False

  • Brackets are supported to control precedence.

Examples:

  • Version named V0000000001: uid == "V0000000001" or uid == "V1" or uid == 1

  • All invalid versions: status == "invalid"

  • All versions older than one week: date < "1 week ago"

  • All versions which have a label named label-1 and are valid: labels["label-1"] and status == "valid"

  • All versions with a name of database-1 or a name of redis-1: name == "database-1" or name == "redis-1"

  • All versions with a name of database-1 or a name of redis-1 that are older than one month: (name == "database-1" or name == "redis-1") and date < "1 month ago"

  • All versions that have a label of label-1 with value example-1: labels["label-1"] == "example-1"

  • All protected versions: protected == True