Create-subst

# Automatically create setters when creating the substitution, inferring
# the setter values.
#
# 1. create a substitution derived from 2 setters.  The user will never
# call the substitution directly, instead it will be computed when the
# setters are used.
kpt cfg create-subst DIR/ image-tag --field-value nginx:v1.7.9 \
  --pattern \${image-setter}:\${tag-setter}

# 2. update the substitution value by setting one of the 2 setters it is
# computed from
kpt cfg set . tag-setter v1.8.0

# Manually create setters and substitution.  This is preferred to configure
# the setters with a type, description, set-by, etc.
#
# 1. create the setter for the image name -- set the field so it isn't
# referenced
kpt cfg create-setter DIR/ image-setter nginx --field "none" \
    --set-by "package-default"

# 2. create the setter for the image tag -- set the field so it isn't
# referenced
kpt cfg create-setter DIR/ tag-setter v1.7.9 --field "none" \
    --set-by "package-default"

# 3. create the substitution computed from the image and tag setters
kpt cfg create-subst DIR/ image-tag nginx:v1.7.9 \
  --pattern \${image-setter}:\${tag-setter}

# 4. update the substitution value by setting one of the setters
kpt cfg set . tag-setter v1.8.0

kpt cfg create-subst DIR NAME --field-value VALUE --pattern PATTERN

DIR
  Path to a package directory

NAME
  The name of the substitution to create.  This is simply the unique key
  which is referenced by fields which have the substitution applied.
  e.g. image-substitution

VALUE
  The current value of the field that will have PATTERN substituted.
  e.g. nginx:1.7.9

PATTERN
  A string containing one or more MARKER substrings which will be
  substituted for setter values.  The pattern may contain multiple
  different MARKERS, the same MARKER multiple times, and non-MARKER
  substrings.
  e.g. ${image-setter}:${tag-setter}

--field string
  name of the field to set -- e.g. --field image

--field-value string
  value of the field to create substitution for -- e.g. --field-value nginx:0.1.0

--pattern string
  substitution pattern -- e.g. --pattern \${my-image-setter}:\${my-tag-setter}

--recurse-subpackages, -R
  create substitution recursively in all the nested subpackages