Documentation
¶
Overview ¶
Package regexpext provides Regexp wrapper types that automatically compile regex strings while they are being unmarshaled from YAML or JSON files. If the compilation fails, the error will be reported as part of the Unmarshal operation.
Index ¶
- type BoundedRegexp
- func (r BoundedRegexp) FindStringSubmatch(in string) []string
- func (r BoundedRegexp) MarshalJSON() ([]byte, error)
- func (r BoundedRegexp) MarshalYAML() (any, error)
- func (r BoundedRegexp) MatchString(in string) bool
- func (r BoundedRegexp) Regexp() (*regexp.Regexp, error)
- func (r *BoundedRegexp) UnmarshalJSON(buf []byte) error
- func (r *BoundedRegexp) UnmarshalYAML(u func(any) error) error
- type ConfigSet
- type PlainRegexp
- func (r PlainRegexp) FindStringSubmatch(in string) []string
- func (r PlainRegexp) MarshalJSON() ([]byte, error)
- func (r PlainRegexp) MarshalYAML() (any, error)
- func (r PlainRegexp) MatchString(in string) bool
- func (r PlainRegexp) Regexp() (*regexp.Regexp, error)
- func (r *PlainRegexp) UnmarshalJSON(buf []byte) error
- func (r *PlainRegexp) UnmarshalYAML(u func(any) error) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type BoundedRegexp ¶
type BoundedRegexp string
BoundedRegexp is like PlainRegexp, but ^ and $ anchors will automatically be added to the start and end of the regexp, respectively. For example, when unmarshaling the value "foo|bar" into a BoundedRegexp, the unmarshaled regexp will be "^(?:foo|bar)$".
During unmarshaling, absent string values will behave the same as empty string values. In both cases, the Regexp will be identical to "^$" and only match empty inputs.
func (BoundedRegexp) FindStringSubmatch ¶
func (r BoundedRegexp) FindStringSubmatch(in string) []string
FindStringSubmatch is a shorthand for `r.Regexp()` followed by `rx.FindStringSubmatch()`. If regex parsing returns an error, this function returns nil.
func (BoundedRegexp) MarshalJSON ¶
func (r BoundedRegexp) MarshalJSON() ([]byte, error)
MarshalJSON implements the json.Marshaler interface.
func (BoundedRegexp) MarshalYAML ¶
func (r BoundedRegexp) MarshalYAML() (any, error)
MarshalYAML implements the yaml.Marshaler interface.
func (BoundedRegexp) MatchString ¶
func (r BoundedRegexp) MatchString(in string) bool
MatchString is a shorthand for `r.Regexp()` followed by `rx.MatchString()`. If regex parsing returns an error, this function returns false.
func (BoundedRegexp) Regexp ¶
func (r BoundedRegexp) Regexp() (*regexp.Regexp, error)
Regexp returns the parsed regexp.Regexp instance for this BoundedRegexp. An error is returned if the regular expression string inside this BoundedRegexp is invalid. If the BoundedRegexp was unmarshaled from JSON or YAML, no error will ever be returned because invalid regex strings were already rejected during unmarshalling.
func (*BoundedRegexp) UnmarshalJSON ¶
func (r *BoundedRegexp) UnmarshalJSON(buf []byte) error
UnmarshalJSON implements the json.Unmarshaler interface.
func (*BoundedRegexp) UnmarshalYAML ¶
func (r *BoundedRegexp) UnmarshalYAML(u func(any) error) error
UnmarshalYAML implements the yaml.Unmarshaler interface.
type ConfigSet ¶
type ConfigSet[K ~string, V any] []struct { Key BoundedRegexp `json:"key" yaml:"key"` Value V `json:"value" yaml:"value"` }
ConfigSet works similar to map[K]V in that it picks values of type V for keys of type K, but the keys in the data structure are actually regexes that can apply to an entire set of K instead of just one specific value of K.
This type is intended to use in configuration, as a substitute for map[K]V that satisfies the DRY rule (Don't Repeat Yourself), or when the full set of relevant keys is not known at config editing time.
func (ConfigSet[K, V]) Pick ¶
func (cs ConfigSet[K, V]) Pick(key K) Option[V]
Pick returns the first value entry whose key regex matches the supplied key, or None if no entry in the ConfigSet matches the key.
func (ConfigSet[K, V]) PickAndFill ¶
func (cs ConfigSet[K, V]) PickAndFill(key K, fill func(value *V, expand func(string) string)) Option[V]
PickAndFill is like Pick, but if the regex in the matching entry contains parenthesized subexpressions (also known as capture groups), the fill callback is used to expand references to the captured texts in the value.
Usage in code looks like this:
type ObjectType string
type MetricSource struct {
PrometheusQuery string
}
var cs ConfigSet[ObjectType, MetricSource]
// omitted: fill `cs` by parsing configuration
objectName := "foo_widget"
metricSource := cs.PickAndFill(objectName, func(ms *MetricSource, expand func(string) string) {
ms.PrometheusQuery = expand(ms.PrometheusQuery)
}).UnwrapOr(MetricSource{})
With this, configuration can be condensed like in the example below:
originalConfig := ConfigSet[ObjectType, MetricSource]{
{ Key: "foo_widget", Value: MetricSource{PrometheusQuery: "count(foo_widgets)"} },
{ Key: "bar_widget", Value: MetricSource{PrometheusQuery: "count(bar_widgets)"} },
{ Key: "qux_widget", Value: MetricSource{PrometheusQuery: "count(qux_widgets)"} },
}
condensedConfig := ConfigSet[ObjectType, MetricSource]{
{ Key: "(foo|bar|qux)_widget", Value: MetricSource{PrometheusQuery: "count(${1}_widgets)"} },
}
Expansion follows the same rules as for regexp.ExpandString() from the standard library.
type PlainRegexp ¶
type PlainRegexp string
PlainRegexp is a regex string that implements the Marshaler and Unmarshaler interfaces for encoding/json and gopkg.in/yaml.v2, respectively. This type also works with gopkg.in/yaml.v3: Even though the Unmarshaler interface has changed in yaml.v3, v3 also still supports the v2 interface. The "PlainRegexp" name is in contrast to type BoundedRegexp, see documentation over there.
During unmarshaling, absent string values will behave the same as empty string values. In both cases, the Regexp will match every input.
func (PlainRegexp) FindStringSubmatch ¶
func (r PlainRegexp) FindStringSubmatch(in string) []string
FindStringSubmatch is a shorthand for `r.Regexp()` followed by `rx.FindStringSubmatch()`. If regex parsing returns an error, this function returns nil.
func (PlainRegexp) MarshalJSON ¶
func (r PlainRegexp) MarshalJSON() ([]byte, error)
MarshalJSON implements the json.Marshaler interface.
func (PlainRegexp) MarshalYAML ¶
func (r PlainRegexp) MarshalYAML() (any, error)
MarshalYAML implements the yaml.Marshaler interface.
func (PlainRegexp) MatchString ¶
func (r PlainRegexp) MatchString(in string) bool
MatchString is a shorthand for `r.Regexp()` followed by `rx.MatchString()`. If regex parsing returns an error, this function returns false.
func (PlainRegexp) Regexp ¶
func (r PlainRegexp) Regexp() (*regexp.Regexp, error)
Regexp returns the parsed regexp.Regexp instance for this PlainRegexp. An error is returned if the regular expression string inside this PlainRegexp is invalid. If the PlainRegexp was unmarshaled from JSON or YAML, no error will ever be returned because invalid regex strings were already rejected during unmarshalling.
func (*PlainRegexp) UnmarshalJSON ¶
func (r *PlainRegexp) UnmarshalJSON(buf []byte) error
UnmarshalJSON implements the json.Unmarshaler interface.
func (*PlainRegexp) UnmarshalYAML ¶
func (r *PlainRegexp) UnmarshalYAML(u func(any) error) error
UnmarshalYAML implements the yaml.Unmarshaler interface.
Source Files