package configs import ( "sort" version "github.com/hashicorp/go-version" "github.com/hashicorp/hcl2/hcl" "github.com/hashicorp/terraform/addrs" ) // BuildConfig constructs a Config from a root module by loading all of its // descendent modules via the given ModuleWalker. // // The result is a module tree that has so far only had basic module- and // file-level invariants validated. If the returned diagnostics contains errors, // the returned module tree may be incomplete but can still be used carefully // for static analysis. func BuildConfig(root *Module, walker ModuleWalker) (*Config, hcl.Diagnostics) { var diags hcl.Diagnostics cfg := &Config{ Module: root, } cfg.Root = cfg // Root module is self-referential. cfg.Children, diags = buildChildModules(cfg, walker) return cfg, diags } func buildChildModules(parent *Config, walker ModuleWalker) (map[string]*Config, hcl.Diagnostics) { var diags hcl.Diagnostics ret := map[string]*Config{} calls := parent.Module.ModuleCalls // We'll sort the calls by their local names so that they'll appear in a // predictable order in any logging that's produced during the walk. callNames := make([]string, 0, len(calls)) for k := range calls { callNames = append(callNames, k) } sort.Strings(callNames) for _, callName := range callNames { call := calls[callName] path := make([]string, len(parent.Path)+1) copy(path, parent.Path) path[len(path)-1] = call.Name req := ModuleRequest{ Name: call.Name, Path: path, SourceAddr: call.SourceAddr, SourceAddrRange: call.SourceAddrRange, VersionConstraint: call.Version, Parent: parent, CallRange: call.DeclRange, } mod, ver, modDiags := walker.LoadModule(&req) diags = append(diags, modDiags...) if mod == nil { // nil can be returned if the source address was invalid and so // nothing could be loaded whatsoever. LoadModule should've // returned at least one error diagnostic in that case. continue } child := &Config{ Parent: parent, Root: parent.Root, Path: path, Module: mod, CallRange: call.DeclRange, SourceAddr: call.SourceAddr, SourceAddrRange: call.SourceAddrRange, Version: ver, } child.Children, modDiags = buildChildModules(child, walker) diags = append(diags, modDiags...) ret[call.Name] = child } return ret, diags } // A ModuleWalker knows how to find and load a child module given details about // the module to be loaded and a reference to its partially-loaded parent // Config. type ModuleWalker interface { // LoadModule finds and loads a requested child module. // // If errors are detected during loading, implementations should return them // in the diagnostics object. If the diagnostics object contains any errors // then the caller will tolerate the returned module being nil or incomplete. // If no errors are returned, it should be non-nil and complete. // // Full validation need not have been performed but an implementation should // ensure that the basic file- and module-validations performed by the // LoadConfigDir function (valid syntax, no namespace collisions, etc) have // been performed before returning a module. LoadModule(req *ModuleRequest) (*Module, *version.Version, hcl.Diagnostics) } // ModuleWalkerFunc is an implementation of ModuleWalker that directly wraps // a callback function, for more convenient use of that interface. type ModuleWalkerFunc func(req *ModuleRequest) (*Module, *version.Version, hcl.Diagnostics) // LoadModule implements ModuleWalker. func (f ModuleWalkerFunc) LoadModule(req *ModuleRequest) (*Module, *version.Version, hcl.Diagnostics) { return f(req) } // ModuleRequest is used with the ModuleWalker interface to describe a child // module that must be loaded. type ModuleRequest struct { // Name is the "logical name" of the module call within configuration. // This is provided in case the name is used as part of a storage key // for the module, but implementations must otherwise treat it as an // opaque string. It is guaranteed to have already been validated as an // HCL identifier and UTF-8 encoded. Name string // Path is a list of logical names that traverse from the root module to // this module. This can be used, for example, to form a lookup key for // each distinct module call in a configuration, allowing for multiple // calls with the same name at different points in the tree. Path addrs.Module // SourceAddr is the source address string provided by the user in // configuration. SourceAddr string // SourceAddrRange is the source range for the SourceAddr value as it // was provided in configuration. This can and should be used to generate // diagnostics about the source address having invalid syntax, referring // to a non-existent object, etc. SourceAddrRange hcl.Range // VersionConstraint is the version constraint applied to the module in // configuration. This data structure includes the source range for // the constraint, which can and should be used to generate diagnostics // about constraint-related issues, such as constraints that eliminate all // available versions of a module whose source is otherwise valid. VersionConstraint VersionConstraint // Parent is the partially-constructed module tree node that the loaded // module will be added to. Callers may refer to any field of this // structure except Children, which is still under construction when // ModuleRequest objects are created and thus has undefined content. // The main reason this is provided is so that full module paths can // be constructed for uniqueness. Parent *Config // CallRange is the source range for the header of the "module" block // in configuration that prompted this request. This can be used as the // subject of an error diagnostic that relates to the module call itself, // rather than to either its source address or its version number. CallRange hcl.Range } // DisabledModuleWalker is a ModuleWalker that doesn't support // child modules at all, and so will return an error if asked to load one. // // This is provided primarily for testing. There is no good reason to use this // in the main application. var DisabledModuleWalker ModuleWalker func init() { DisabledModuleWalker = ModuleWalkerFunc(func(req *ModuleRequest) (*Module, *version.Version, hcl.Diagnostics) { return nil, nil, hcl.Diagnostics{ { Severity: hcl.DiagError, Summary: "Child modules are not supported", Detail: "Child module calls are not allowed in this context.", Subject: &req.CallRange, }, } }) }