3728d0ae2e
The logic to deserialise a structure from *either* JSON or YAML is reused several times and can be easily extracted, which this commit does.
107 lines
3.1 KiB
Go
107 lines
3.1 KiB
Go
package context
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import (
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"path"
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"github.com/polydawn/meep"
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"github.com/tazjin/kontemplate/util"
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)
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type ResourceSet struct {
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Name string `json:"name"`
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Values map[string]interface{} `json:"values"`
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// Fields for resource set collections
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Include []ResourceSet `json:"include"`
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Parent string
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}
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type Context struct {
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Name string `json:"context"`
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Global map[string]interface{} `json:"global"`
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ResourceSets []ResourceSet `json:"include"`
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BaseDir string
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}
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type ContextLoadingError struct {
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meep.AllTraits
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Filename string
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}
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// Attempt to load and deserialise a Context from the specified file.
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func LoadContextFromFile(filename string) (*Context, error) {
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var c Context
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err := util.LoadJsonOrYaml(filename, &c)
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if err != nil {
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return nil, meep.New(
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&ContextLoadingError{Filename: filename},
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meep.Cause(err),
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)
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}
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c.ResourceSets = flattenResourceSetCollections(&c.ResourceSets)
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c.BaseDir = path.Dir(filename)
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c.ResourceSets = loadAllDefaultValues(&c)
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return &c, nil
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}
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// Flattens resource set collections, i.e. resource sets that themselves have an additional 'include' field set.
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// Those will be regarded as a short-hand for including multiple resource sets from a subfolder.
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// See https://github.com/tazjin/kontemplate/issues/9 for more information.
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func flattenResourceSetCollections(rs *[]ResourceSet) []ResourceSet {
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flattened := make([]ResourceSet, 0)
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for _, r := range *rs {
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if len(r.Include) == 0 {
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flattened = append(flattened, r)
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} else {
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for _, subResourceSet := range r.Include {
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subResourceSet.Parent = r.Name
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subResourceSet.Name = path.Join(r.Name, subResourceSet.Name)
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subResourceSet.Values = *util.Merge(&r.Values, &subResourceSet.Values)
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flattened = append(flattened, subResourceSet)
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}
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}
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}
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return flattened
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}
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func loadAllDefaultValues(c *Context) []ResourceSet {
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updated := make([]ResourceSet, len(c.ResourceSets))
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for i, rs := range c.ResourceSets {
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merged := loadDefaultValues(&rs, c)
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rs.Values = *merged
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updated[i] = rs
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}
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return updated
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}
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// Loads and merges default values for a resource set collection from path/to/set/default.{json|yaml}.
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// YAML takes precedence over JSON.
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// Default values in resource set collections have the lowest priority possible.
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func loadDefaultValues(rs *ResourceSet, c *Context) *map[string]interface{} {
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var defaultVars map[string]interface{}
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// Attempt to load YAML values
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err := util.LoadJsonOrYaml(path.Join(c.BaseDir, rs.Name, "default.yaml"), &defaultVars)
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if err == nil {
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return util.Merge(&defaultVars, &rs.Values)
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}
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// Attempt to load JSON values
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err = util.LoadJsonOrYaml(path.Join(c.BaseDir, rs.Name, "default.json"), &defaultVars)
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if err == nil {
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return util.Merge(&defaultVars, &rs.Values)
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}
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// The actual error is not inspected here. The reasoning for this is that in case of serious problems (e.g.
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// permission issues with the folder / folder not existing) failure will occur a bit later anyways.
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// Otherwise we'd have to differentiate between file-not-found-errors (no default values specified) and other
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// errors here.
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return &rs.Values
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}
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