terraform/config/config_tree.go

69 lines
1.5 KiB
Go

package config
// configTree represents a tree of configurations where the root is the
// first file and its children are the configurations it has imported.
type configTree struct {
Path string
Config *Config
Children []*configTree
}
// Flatten flattens the entire tree down to a single merged Config
// structure.
func (t *configTree) Flatten() (*Config, error) {
// No children is easy: we're already merged!
if len(t.Children) == 0 {
return t.Config, nil
}
// Depth-first, merge all the children first.
childConfigs := make([]*Config, len(t.Children))
for i, ct := range t.Children {
c, err := ct.Flatten()
if err != nil {
return nil, err
}
childConfigs[i] = c
}
// Merge all the children in order
config := childConfigs[0]
childConfigs = childConfigs[1:]
for _, config2 := range childConfigs {
var err error
config, err = mergeConfig(config, config2)
if err != nil {
return nil, err
}
}
// Merge the final merged child config with our own
return mergeConfig(config, t.Config)
}
func mergeConfig(c1, c2 *Config) (*Config, error) {
c := new(Config)
// Merge variables: Variable merging is quite simple. Set fields in
// later set variables override those earlier.
c.Variables = c1.Variables
for k, v2 := range c2.Variables {
v1, ok := c.Variables[k]
if ok {
if v2.Default == "" {
v2.Default = v1.Default
}
if v2.Description == "" {
v2.Description = v1.Description
}
}
c.Variables[k] = v2
}
// TODO: merge resources
return c, nil
}