feat context: Support resource set default values

This adds functionality to specify default values directly in resource sets.

The idea is that users can create a file called `values.yaml` or `values.json`
in a resource set's folder and have all variables specified in that file be
automatically merged into the resource set variables with the lowest priority.

This fixes #25
This fixes #30 (to a degree)
This commit is contained in:
Vincent Ambo 2017-04-04 14:28:22 +02:00
parent 4eadb58841
commit 11cfc80020
4 changed files with 65 additions and 3 deletions

View file

@ -64,8 +64,9 @@ func LoadContextFromFile(filename string) (*Context, error) {
) )
} }
c.ResourceSets = *flattenResourceSetCollections(&c.ResourceSets) c.ResourceSets = flattenResourceSetCollections(&c.ResourceSets)
c.BaseDir = path.Dir(filename) c.BaseDir = path.Dir(filename)
c.ResourceSets = loadAllDefaultValues(&c)
return &c, nil return &c, nil
} }
@ -73,7 +74,7 @@ func LoadContextFromFile(filename string) (*Context, error) {
// Flattens resource set collections, i.e. resource sets that themselves have an additional 'include' field set. // Flattens resource set collections, i.e. resource sets that themselves have an additional 'include' field set.
// Those will be regarded as a short-hand for including multiple resource sets from a subfolder. // Those will be regarded as a short-hand for including multiple resource sets from a subfolder.
// See https://github.com/tazjin/kontemplate/issues/9 for more information. // See https://github.com/tazjin/kontemplate/issues/9 for more information.
func flattenResourceSetCollections(rs *[]ResourceSet) *[]ResourceSet { func flattenResourceSetCollections(rs *[]ResourceSet) []ResourceSet {
flattened := make([]ResourceSet, 0) flattened := make([]ResourceSet, 0)
for _, r := range *rs { for _, r := range *rs {
@ -89,5 +90,44 @@ func flattenResourceSetCollections(rs *[]ResourceSet) *[]ResourceSet {
} }
} }
return &flattened return flattened
}
func loadAllDefaultValues(c *Context) []ResourceSet {
updated := make([]ResourceSet, len(c.ResourceSets))
for i, rs := range c.ResourceSets {
merged := loadDefaultValues(&rs, c)
rs.Values = *merged
updated[i] = rs
}
return updated
}
// Loads and merges default values for a resource set collection from path/to/set/default.{json|yaml}.
// YAML takes precedence over JSON.
// Default values in resource set collections have the lowest priority possible.
func loadDefaultValues(rs *ResourceSet, c *Context) *map[string]interface{} {
var defaultVars map[string]interface{}
// Attempt to load YAML values
y, err := ioutil.ReadFile(path.Join(c.BaseDir, rs.Name, "default.yaml"))
if err == nil {
yaml.Unmarshal(y, &defaultVars)
return util.Merge(&defaultVars, &rs.Values)
}
// Attempt to load JSON values
j, err := ioutil.ReadFile(path.Join(c.BaseDir, rs.Name, "default.json"))
if err == nil {
json.Unmarshal(j, &defaultVars)
return util.Merge(&defaultVars, &rs.Values)
}
// The actual error is not inspected here. The reasoning for this is that in case of serious problems (e.g.
// permission issues with the folder / folder not existing) failure will occur a bit later anyways.
// Otherwise we'd have to differentiate between file-not-found-errors (no default values specified) and other
// errors here.
return &rs.Values
} }

View file

@ -140,3 +140,17 @@ func TestSubresourceVariableInheritanceOverride(t *testing.T) {
t.Fail() t.Fail()
} }
} }
func TestDefaultValuesLoading(t *testing.T) {
ctx, err := LoadContextFromFile("testdata/default-loading.yaml")
if err != nil {
t.Error(err)
t.Fail()
}
rs := ctx.ResourceSets[0]
if rs.Values["defaultValues"] != "loaded" {
t.Errorf("Default values not loaded from YAML file")
t.Fail()
}
}

6
context/testdata/default-loading.yaml vendored Normal file
View file

@ -0,0 +1,6 @@
---
context: default-loading
include:
- name: default
values:
override: notAtAll

2
context/testdata/default/default.yaml vendored Normal file
View file

@ -0,0 +1,2 @@
defaultValues: loaded
override: noop