terraform/config/merge.go

83 lines
2.1 KiB
Go

package config
import (
"fmt"
)
// Merge merges two configurations into a single configuration.
//
// Merge allows for the two configurations to have duplicate resources,
// because the resources will be merged. This differs from a single
// Config which must only have unique resources.
func Merge(c1, c2 *Config) (*Config, error) {
c := new(Config)
// Merge unknown keys
unknowns := make(map[string]struct{})
for _, k := range c1.unknownKeys {
unknowns[k] = struct{}{}
}
for _, k := range c2.unknownKeys {
unknowns[k] = struct{}{}
}
for k, _ := range unknowns {
c.unknownKeys = append(c.unknownKeys, k)
}
// 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
}
// Merge outputs: If they collide, just take the latest one for now. In
// the future, we might provide smarter merge functionality.
c.Outputs = make(map[string]*Output)
for k, v := range c1.Outputs {
c.Outputs[k] = v
}
for k, v := range c2.Outputs {
c.Outputs[k] = v
}
// Merge provider configs: If they collide, we just take the latest one
// for now. In the future, we might provide smarter merge functionality.
c.ProviderConfigs = make(map[string]*ProviderConfig)
for k, v := range c1.ProviderConfigs {
c.ProviderConfigs[k] = v
}
for k, v := range c2.ProviderConfigs {
c.ProviderConfigs[k] = v
}
// Merge resources: If they collide, we just take the latest one
// for now. In the future, we might provide smarter merge functionality.
resources := make(map[string]*Resource)
for _, r := range c1.Resources {
id := fmt.Sprintf("%s[%s]", r.Type, r.Name)
resources[id] = r
}
for _, r := range c2.Resources {
id := fmt.Sprintf("%s[%s]", r.Type, r.Name)
resources[id] = r
}
c.Resources = make([]*Resource, 0, len(resources))
for _, r := range resources {
c.Resources = append(c.Resources, r)
}
return c, nil
}