88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
package config
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import (
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"fmt"
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)
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// configTree represents a tree of configurations where the root is the
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// first file and its children are the configurations it has imported.
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type configTree struct {
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Path string
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Config *Config
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Children []*configTree
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}
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// Flatten flattens the entire tree down to a single merged Config
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// structure.
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func (t *configTree) Flatten() (*Config, error) {
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// No children is easy: we're already merged!
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if len(t.Children) == 0 {
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return t.Config, nil
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}
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// Depth-first, merge all the children first.
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childConfigs := make([]*Config, len(t.Children))
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for i, ct := range t.Children {
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c, err := ct.Flatten()
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if err != nil {
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return nil, err
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}
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childConfigs[i] = c
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}
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// Merge all the children in order
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config := childConfigs[0]
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childConfigs = childConfigs[1:]
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for _, config2 := range childConfigs {
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var err error
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config, err = mergeConfig(config, config2)
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if err != nil {
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return nil, err
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}
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}
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// Merge the final merged child config with our own
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return mergeConfig(config, t.Config)
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}
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func mergeConfig(c1, c2 *Config) (*Config, error) {
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c := new(Config)
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// Merge variables: Variable merging is quite simple. Set fields in
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// later set variables override those earlier.
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c.Variables = c1.Variables
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for k, v2 := range c2.Variables {
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v1, ok := c.Variables[k]
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if ok {
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if v2.Default == "" {
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v2.Default = v1.Default
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}
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if v2.Description == "" {
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v2.Description = v1.Description
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}
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}
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c.Variables[k] = v2
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}
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// Merge resources: If they collide, we just take the latest one
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// for now. In the future, we might provide smarter merge functionality.
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resources := make(map[string]*Resource)
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for _, r := range c1.Resources {
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id := fmt.Sprintf("%s[%s]", r.Type, r.Name)
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resources[id] = r
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}
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for _, r := range c2.Resources {
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id := fmt.Sprintf("%s[%s]", r.Type, r.Name)
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resources[id] = r
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}
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c.Resources = make([]*Resource, 0, len(resources))
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for _, r := range resources {
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c.Resources = append(c.Resources, r)
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}
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return c, nil
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}
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