terraform/module_dependencies.go

   1 package terraform
   2
   3 import (
   4         "github.com/hashicorp/terraform/config"
   5         "github.com/hashicorp/terraform/config/module"
   6         "github.com/hashicorp/terraform/moduledeps"
   7         "github.com/hashicorp/terraform/plugin/discovery"
   8 )
   9
  10 // ModuleTreeDependencies returns the dependencies of the tree of modules
  11 // described by the given configuration tree and state.
  12 //
  13 // Both configuration and state are required because there can be resources
  14 // implied by instances in the state that no longer exist in config.
  15 //
  16 // This function will panic if any invalid version constraint strings are
  17 // present in the configuration. This is guaranteed not to happen for any
  18 // configuration that has passed a call to Config.Validate().
  19 func ModuleTreeDependencies(root *module.Tree, state *State) *moduledeps.Module {
  20         // First we walk the configuration tree to build the overall structure
  21         // and capture the explicit/implicit/inherited provider dependencies.
  22         deps := moduleTreeConfigDependencies(root, nil)
  23
  24         // Next we walk over the resources in the state to catch any additional
  25         // dependencies created by existing resources that are no longer in config.
  26         // Most things we find in state will already be present in 'deps', but
  27         // we're interested in the rare thing that isn't.
  28         moduleTreeMergeStateDependencies(deps, state)
  29
  30         return deps
  31 }
  32
  33 func moduleTreeConfigDependencies(root *module.Tree, inheritProviders map[string]*config.ProviderConfig) *moduledeps.Module {
  34         if root == nil {
  35                 // If no config is provided, we'll make a synthetic root.
  36                 // This isn't necessarily correct if we're called with a nil that
  37                 // *isn't* at the root, but in practice that can never happen.
  38                 return &moduledeps.Module{
  39                         Name: "root",
  40                 }
  41         }
  42
  43         ret := &moduledeps.Module{
  44                 Name: root.Name(),
  45         }
  46
  47         cfg := root.Config()
  48         providerConfigs := cfg.ProviderConfigsByFullName()
  49
  50         // Provider dependencies
  51         {
  52                 providers := make(moduledeps.Providers, len(providerConfigs))
  53
  54                 // Any providerConfigs elements are *explicit* provider dependencies,
  55                 // which is the only situation where the user might provide an actual
  56                 // version constraint. We'll take care of these first.
  57                 for fullName, pCfg := range providerConfigs {
  58                         inst := moduledeps.ProviderInstance(fullName)
  59                         versionSet := discovery.AllVersions
  60                         if pCfg.Version != "" {
  61                                 versionSet = discovery.ConstraintStr(pCfg.Version).MustParse()
  62                         }
  63                         providers[inst] = moduledeps.ProviderDependency{
  64                                 Constraints: versionSet,
  65                                 Reason:      moduledeps.ProviderDependencyExplicit,
  66                         }
  67                 }
  68
  69                 // Each resource in the configuration creates an *implicit* provider
  70                 // dependency, though we'll only record it if there isn't already
  71                 // an explicit dependency on the same provider.
  72                 for _, rc := range cfg.Resources {
  73                         fullName := rc.ProviderFullName()
  74                         inst := moduledeps.ProviderInstance(fullName)
  75                         if _, exists := providers[inst]; exists {
  76                                 // Explicit dependency already present
  77                                 continue
  78                         }
  79
  80                         reason := moduledeps.ProviderDependencyImplicit
  81                         if _, inherited := inheritProviders[fullName]; inherited {
  82                                 reason = moduledeps.ProviderDependencyInherited
  83                         }
  84
  85                         providers[inst] = moduledeps.ProviderDependency{
  86                                 Constraints: discovery.AllVersions,
  87                                 Reason:      reason,
  88                         }
  89                 }
  90
  91                 ret.Providers = providers
  92         }
  93
  94         childInherit := make(map[string]*config.ProviderConfig)
  95         for k, v := range inheritProviders {
  96                 childInherit[k] = v
  97         }
  98         for k, v := range providerConfigs {
  99                 childInherit[k] = v
 100         }
 101         for _, c := range root.Children() {
 102                 ret.Children = append(ret.Children, moduleTreeConfigDependencies(c, childInherit))
 103         }
 104
 105         return ret
 106 }
 107
 108 func moduleTreeMergeStateDependencies(root *moduledeps.Module, state *State) {
 109         if state == nil {
 110                 return
 111         }
 112
 113         findModule := func(path []string) *moduledeps.Module {
 114                 module := root
 115                 for _, name := range path[1:] { // skip initial "root"
 116                         var next *moduledeps.Module
 117                         for _, cm := range module.Children {
 118                                 if cm.Name == name {
 119                                         next = cm
 120                                         break
 121                                 }
 122                         }
 123
 124                         if next == nil {
 125                                 // If we didn't find a next node, we'll need to make one
 126                                 next = &moduledeps.Module{
 127                                         Name: name,
 128                                 }
 129                                 module.Children = append(module.Children, next)
 130                         }
 131
 132                         module = next
 133                 }
 134                 return module
 135         }
 136
 137         for _, ms := range state.Modules {
 138                 module := findModule(ms.Path)
 139
 140                 for _, is := range ms.Resources {
 141                         fullName := config.ResourceProviderFullName(is.Type, is.Provider)
 142                         inst := moduledeps.ProviderInstance(fullName)
 143                         if _, exists := module.Providers[inst]; !exists {
 144                                 if module.Providers == nil {
 145                                         module.Providers = make(moduledeps.Providers)
 146                                 }
 147                                 module.Providers[inst] = moduledeps.ProviderDependency{
 148                                         Constraints: discovery.AllVersions,
 149                                         Reason:      moduledeps.ProviderDependencyFromState,
 150                                 }
 151                         }
 152                 }
 153         }
 154
 155 }