yq/pkg/yqlib/doc/usage/properties.md

Properties

Encode/Decode/Roundtrip to/from a property file. Line comments on value nodes will be copied across.

By default, empty maps and arrays are not encoded - see below for an example on how to encode a value for these.

Encode properties

Note that empty arrays and maps are not encoded by default.

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props sample.yml

will output

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets.0 = cat
person.pets.1.nested.0 = list entry
person.food.0 = pizza

Encode properties with array brackets

Declare the --properties-array-brackets flag to give array paths in brackets (e.g. SpringBoot).

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props --properties-array-brackets sample.yml

will output

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets[0] = cat
person.pets[1].nested[0] = list entry
person.food[0] = pizza

Encode properties - custom separator

Use the --properties-customer-separator flag to specify your own key/value separator.

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props --properties-customer-separator=" :@ " sample.yml

will output

# block comments come through
# comments on values appear
person.name :@ Mike Wazowski

# comments on array values appear
person.pets.0 :@ cat
person.pets.1.nested.0 :@ list entry
person.food.0 :@ pizza

Encode properties: scalar encapsulation

Note that string values with blank characters in them are encapsulated with double quotes

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props --unwrapScalar=false sample.yml

will output

# block comments come through
# comments on values appear
person.name = "Mike Wazowski"

# comments on array values appear
person.pets.0 = cat
person.pets.1.nested.0 = "list entry"
person.food.0 = pizza

Encode properties: no comments

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props '... comments = ""' sample.yml

will output

person.name = Mike Wazowski
person.pets.0 = cat
person.pets.1.nested.0 = list entry
person.food.0 = pizza

Encode properties: include empty maps and arrays

Use a yq expression to set the empty maps and sequences to your desired value.

Given a sample.yml file of:

# block comments come through
person: # neither do comments on maps
    name: Mike Wazowski # comments on values appear
    pets: 
    - cat # comments on array values appear
    - nested:
        - list entry
    food: [pizza] # comments on arrays do not
emptyArray: []
emptyMap: []

then

yq -o=props '(.. | select( (tag == "!!map" or tag =="!!seq") and length == 0)) = ""' sample.yml

will output

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets.0 = cat
person.pets.1.nested.0 = list entry
person.food.0 = pizza
emptyArray = 
emptyMap = 

Decode properties

Given a sample.properties file of:

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets.0 = cat
person.pets.1.nested.0 = list entry
person.food.0 = pizza

then

yq -p=props sample.properties

will output

person:
  # block comments come through
  # comments on values appear
  name: Mike Wazowski
  pets:
    # comments on array values appear
    - cat
    - nested:
        - list entry
  food:
    - pizza

Decode properties: numbers

All values are assumed to be strings when parsing properties, but you can use the from_yaml operator on all the strings values to autoparse into the correct type.

Given a sample.properties file of:

a.b = 10

then

yq -p=props ' (.. | select(tag == "!!str")) |= from_yaml' sample.properties

will output

a:
  b: 10

Decode properties - array should be a map

If you have a numeric map key in your property files, use array_to_map to convert them to maps.

Given a sample.properties file of:

things.10 = mike

then

yq -p=props '.things |= array_to_map' sample.properties

will output

things:
  10: mike

Roundtrip

Given a sample.properties file of:

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets.0 = cat
person.pets.1.nested.0 = list entry
person.food.0 = pizza

then

yq -p=props -o=props '.person.pets.0 = "dog"' sample.properties

will output

# block comments come through
# comments on values appear
person.name = Mike Wazowski

# comments on array values appear
person.pets.0 = dog
person.pets.1.nested.0 = list entry
person.food.0 = pizza