Classes and utility functions

Class srlinux.data.ColumnFormatter(ancestor_keys=True, horizontal_alignment=None, vertical_alignment=None, borders=None

Formats the specific Data object as a column-based table. For example:

+----------+-------------------+--------------------+---------------+
| Entry id |     Ip prefix     |  Origin protocol   |   Next hop    |
+==========+===================+====================+===============+
| 1        | 1.1.2.0/24        | local_aggregate    | None          |
| 2        | 1.1.2.2/32        | directly_connected | None          |
+----------+-------------------+--------------------+---------------+

The output can be customized using the following constructor arguments:

ancestor_keys : bool or list

The bool construct controls whether the ancestor keys are added as columns to the output table:

• True - (the default) includes all ancestor keys

• False - does not include any ancestor keys

A list provides more granular control. The list must contain a value for each ancestor key, and can contain:

• None - suppresses the key

• A string to specify the column key to use for the ancestor key

For example, when passed [None, ‟A”, None], the first and third ancestor key are dropped, and the second is renamed to ‟A”.

horizontal_alignment : dict{str: Alignment}

Dictionary mapping column-names to their horizontal alignment (Alignment.Left/Center/Right). Columns not mentioned are left-aligned.

vertical_alignment : dict{str: Alignment}

Dictionary mapping column-names to their vertical alignment (Alignment.Top/Middle/Bottom). Columns not mentioned are top-aligned.

borders : Borders

Combination of Borders values indicating which borders to print. Defaults to ‟Borders.Outside | Borders.Header | Borders.Columns”.

Class srlinux.data.Alignment

The values used to align data in the table cells. The following table lists the alignment values.

Table 2. Cell alignment values

Alignment value	Description
Left= 1	Horizontally aligns the data to the left
Right= 2	Horizontally aligns the data to the right
Center= 3	Horizontally centers the data
Top= 4	Vertically aligns the data to the top
Middle= 5	Vertically centers the data
Bottom= 6	Vertically aligns the data to the bottom

Class srlinux.data.Borders

Specifies border type when drawing a table. Values can be combined together using the symbol ‛|’. For example: Borders.Outside | Borders.Header draws a border around the table and a line below the header. The following table defines the border values to use when drawing a table.

Table 3. Types of table borders

Table border	Description
Nothing= 0	Draws no borders
Outside= 1	Draws a border around the table
Header= 2	Draws a horizontal line between the header and the first row
Rows= 4	Draws a horizontal line between the rows
Columns= 8	Draws a vertical line between the columns

Class srlinux.data.TagValueFormatter(filter=None)

Formats the specified Data object as a list of ‟tag: value” pairs (one on each line). For example:

key  : <name>
field: <value>

Class srlinux.data.TagValueWithKeyLineFormatter(filter=None)

Formats the specified Data object as a single line with the name and the keys, followed by a list of ‟tag: value” pairs (one on each line). For example:

node <name> id <id>
 field: <value>

Class srlinux.data.Indent(formatter, indentation=' ')

Decorator that indents every line printed by the wrapped formatter. For example:

Indent(MyOtherFormatter(), 6)
Indent(MyOtherFormatter(), '      ')

Either of the examples shown above adds six spaces before every line printed by MyOtherFormatter. The following table defines the indent arguments.

Table 4. Indent arguments

Argument	Description
indentation: str or int	The indent string put before every line, or an integer that indicates the amount of spaces to add.

Class srlinux.data.Border(formatter, position=None, character='-')

Decorator that prints a border line above, below, or above and below another formatter. For example:

Border(MyOtherFormatter(), Border.Above | Border.Below, '+')

This example prints a border line of ++++++++++ above and below the output of the other formatter. The following table lists the border line arguments.

Table 5. Border line arguments

Argument	Description
position : Border	Controls where the border lines are drawn. Multiple values can be combined together using the ‟|” symbol.
Border.Above	Prints a line above the first Data entry. Defaults to printing a line above and below.
Border.Below	Prints a line below the last Data entry. Defaults to printing a line above and below.
Border.Between	Prints a line between each Data entry. Defaults to printing a line above and below.
character: char (optional)	Defines the character used to draw the border line. Defaults to ‟-”.

Class srlinux.data.Header(formatter, text, character='-')

Decorator that prints a header above another formatter. For example:

Header(
    MyOtherFormatter(),
    text='The header text',
    character='+'
)

This example prints:

++++++++++++++++++++++++
The header text
++++++++++++++++++++++++
<snip here is the output of MyOtherFormatter>

The following table defines the header arguments.

Table 6. Header arguments

Argument	Description
text: str	Defines the header text, which can contain new lines.
character: char (optional)	Defines the character used to draw the border. Defaults to ‟-”.

Class srlinux.data.Footer(formatter, text, character='-')

Decorator that prints a footer below another formatter. For example:

Footer(
    MyOtherFormatter(),
    text='The footer text',
    character='+'
)

This example prints:

<snip here is the output of MyOtherFormatter>
++++++++++++++++++++++++
The footer text
++++++++++++++++++++++++

The following table defines the footer arguments.

Table 7. Footer arguments

Argument	Description
text: str	Defines the footer text, which can contain new lines.
character: char	Defines the character used to draw the border. Defaults to ‟-”.

iClass srlinux.data.Whiteline(formatter, position=None)

Decorator that prints an empty line above, below, and between entries of another formatter. For example:

Whiteline(MyOtherFormatter(), Whiteline.Above | Whiteline.Below)

This example prints an empty line above and below the output of the other formatter.

The following table defines the Whiteline arguments.

Table 8. Whiteline arguments

Argument	Description
position : Whiteline	Controls where the empty lines are drawn. Multiple values can be combined together using ‟|”.
Whiteline.Above	Prints a line above the first Data entry. Defaults to printing a line above and below.
Whiteline.Below	Prints a line below the last Data entry. Defaults to printing a line above and below.
Whiteline.Between	Prints a line between each Data entry. Defaults to printing a line above and below.

iClass srlinux.data.FilteredFormatter(formatter, schema, fields=[], leaflists=[])

Decorator that only displays the selected fields and leaf-lists. For example:

FilteredFormatter(
    MyOtherFormatter(),
    schema=data.schema,
    fields=['field-to-keep', 'other-field-to-keep'],
    leaflists=['leaflist-to-keep', 'other-leaflist-to-keep'],
)

A common use case for this decorator is to enhance the format of some fields, but keeps the original field values available for when the output is formatted as JSON.

For the next example, both the original fields and the combined field are added to the Data object, and the original fields are filtered out for formatting.

data = Data(schema)

# The 2 original fields. Added to data so that 'show <snip> | as json' displays them
 in a useful fashion.
data.source = '1.2.3.4'
data.destination = '5.6.7.8'

# The combined field we want to show in the show report.
data.flow = f'{data.source} -> {data.destination}'

# Only show the combined field in the show report.
data.formatter = FilteredFormatter(
    TagValueFormatter(),
    schema=data.schema,
    fields=['flow']
)

The following table defines the available FilteredFormatter arguments.

Table 9. FilteredFormatter arguments

Argument	Description
schema : SchemaNode	Defines the schema of the Data object this formatter is applied to
fields : list of str	Defines the names of the fields to display. Any field not mentioned is omitted from the output. The default is to remove all fields.
leaflists : list of str	Defines the names of the leaf-lists to display. Any leaf-list not mentioned is omitted from the output. The default is to remove all leaf-lists.

iClass srlinux.data.ColumnPrinter(columns, max_width, horizontal_alignment, vertical_alignment, borders, filter=None)

Utility class to print a set of rows as a column-based table. For example:

+----------+-------------------+
| Entry id |     Ip prefix     |
+==========+===================+
| 1        | 1.1.2.0/24        |
| 2        | 1.1.2.2/32        |
+----------+-------------------+

This output is generated with the following:

printer = ColumnPrinter(['Entry id', 'Ip prefix'], borders=Borders.Outside, max_widt
h=80)

printer.add_row([1, '1.1.2.0/24'])
printer.add_row([2, '1.1.2.2/32'])

printer.iter_format()
# Returns
# (
#    '+----------+-------------------+',
#    '| Entry id |     Ip prefix     |',
#    '+==========+===================+',
#    '| 1        | 1.1.2.0/24        |',
#    '| 2        | 1.1.2.2/32        |',
#    '+----------+-------------------+'
# )

The following table defines the constructor arguments that can be used to customize the output.

Table 10. ColumnPrinter constructor arguments

Constructor argument	Description
horizontal_alignment : dict{str: Alignment}	Dictionary mapping of column-names to their horizontal alignment (Alignment.Left/Center/Right). Columns not mentioned here are left-aligned.
vertical_alignment : dict{str: Alignment}	Dictionary mapping of column-names to their vertical alignment (Alignment.Top/Middle/Bottom). Columns not mentioned here are top-aligned.
borders : Borders	Combining borders values that indicate what borders can be drawn. Defaults to ‟Borders.Outside | Borders.Header | Borders.Columns”.
filter : Filter	Filters out fields from the output. Fields that do not match the filter are not printed.

iClass srlinux.data.TagValuePrinter(tags, max_width, filter=None)

Utility class to print a set of ‟tag: value” pairs. For example:

printer = TagValuePrinter(['first', 'second'], max_width=80)
printer.iter_format(['value', 'other-value'])
# Returns (
#    'first : value',
#    'second: other-value',
# )

If None (or ‛’ or []) is passed in as a value, the item is skipped in the output:

printer.iter_format([None, 'other-value'])
# Returns (
#    'second: other-value',
# )

The following table defines the TagValuePrinter arguments.

Table 11. TagValuePrinter arguments

Argument	Description
filter : Filter	Filters out fields/leaf-lists from the output. Fields that do not match the filter are not printed.

iClass srlinux.data.TagValueWithKeyLinePrinter(name, keys, tags, max_width, filter=None)

Utility class to print a single line with the name and the keys, followed by a list of ‟tag: value” pairs (one on each line). For example:

node <name> id <id>
 field: <value>

The following is an example of this usage:

printer = TagValueWithKeyLinePrinter(name='node', keys=['key'], tags=['first-
field', 'second-field'], max_width=80)
printer.iter_format(keys=[<name>], values=['value', 'other-value'])
# Returns (
#    'node <name>',
#    '  first-field : value',
#    '  second-field: other-value',
# )

If None (or ‛’ or []) is passed in as a value, the item is skipped in the output:

printer.iter_format(keys=['<name>'], [None, 'other-value'])
# Returns (
#    'node <name>',
#    '  second-field: other-value',
# )

The following table defines theTagValueWithKeyLinePrinter arguments.

Table 12. TagValueWithKeyLinePrinter arguments

Argument	Description
filter : Filter	Filters out fields/leaf-lists from the output. Fields that do not match the filter are not printed.

srlinux.data.print_line(width, character='-')

Returns a line of length ‟width”, consisting of the specified character.

srlinux.data.print_double_line(width)

Returns a line of length ‟width” consisting of ============.

srlinux.data.indent(values, indentation)

Indents each value with the specified indentation. The indentation can either be a string, or an integer indicating the number of spaces to use for the indentation.

srlinux.data.format_value(value)

Formats the Data value as a string, which works for key, field, and leaf-list values of all accepted types (number, string, bool), even if the field/leaf-list is absent.