terraform/addrs/module_instance.go

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package addrs
import (
"bytes"
"fmt"
"github.com/hashicorp/hcl2/hcl"
"github.com/hashicorp/hcl2/hcl/hclsyntax"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/gocty"
"github.com/hashicorp/terraform/tfdiags"
)
// ModuleInstance is an address for a particular module instance within the
// dynamic module tree. This is an extension of the static traversals
// represented by type Module that deals with the possibility of a single
// module call producing multiple instances via the "count" and "for_each"
// arguments.
//
// Although ModuleInstance is a slice, it should be treated as immutable after
// creation.
type ModuleInstance []ModuleInstanceStep
var (
_ Targetable = ModuleInstance(nil)
)
func ParseModuleInstance(traversal hcl.Traversal) (ModuleInstance, tfdiags.Diagnostics) {
mi, remain, diags := parseModuleInstancePrefix(traversal)
if len(remain) != 0 {
if len(remain) == len(traversal) {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid module instance address",
Detail: "A module instance address must begin with \"module.\".",
Subject: remain.SourceRange().Ptr(),
})
} else {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid module instance address",
Detail: "The module instance address is followed by additional invalid content.",
Subject: remain.SourceRange().Ptr(),
})
}
}
return mi, diags
}
// ParseModuleInstanceStr is a helper wrapper around ParseModuleInstance
// that takes a string and parses it with the HCL native syntax traversal parser
// before interpreting it.
//
// This should be used only in specialized situations since it will cause the
// created references to not have any meaningful source location information.
// If a reference string is coming from a source that should be identified in
// error messages then the caller should instead parse it directly using a
// suitable function from the HCL API and pass the traversal itself to
// ParseProviderConfigCompact.
//
// Error diagnostics are returned if either the parsing fails or the analysis
// of the traversal fails. There is no way for the caller to distinguish the
// two kinds of diagnostics programmatically. If error diagnostics are returned
// then the returned address is invalid.
func ParseModuleInstanceStr(str string) (ModuleInstance, tfdiags.Diagnostics) {
var diags tfdiags.Diagnostics
traversal, parseDiags := hclsyntax.ParseTraversalAbs([]byte(str), "", hcl.Pos{Line: 1, Column: 1})
diags = diags.Append(parseDiags)
if parseDiags.HasErrors() {
return nil, diags
}
addr, addrDiags := ParseModuleInstance(traversal)
diags = diags.Append(addrDiags)
return addr, diags
}
func parseModuleInstancePrefix(traversal hcl.Traversal) (ModuleInstance, hcl.Traversal, tfdiags.Diagnostics) {
remain := traversal
var mi ModuleInstance
var diags tfdiags.Diagnostics
for len(remain) > 0 {
var next string
switch tt := remain[0].(type) {
case hcl.TraverseRoot:
next = tt.Name
case hcl.TraverseAttr:
next = tt.Name
default:
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid address operator",
Detail: "Module address prefix must be followed by dot and then a name.",
Subject: remain[0].SourceRange().Ptr(),
})
break
}
if next != "module" {
break
}
kwRange := remain[0].SourceRange()
remain = remain[1:]
// If we have the prefix "module" then we should be followed by an
// module call name, as an attribute, and then optionally an index step
// giving the instance key.
if len(remain) == 0 {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid address operator",
Detail: "Prefix \"module.\" must be followed by a module name.",
Subject: &kwRange,
})
break
}
var moduleName string
switch tt := remain[0].(type) {
case hcl.TraverseAttr:
moduleName = tt.Name
default:
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid address operator",
Detail: "Prefix \"module.\" must be followed by a module name.",
Subject: remain[0].SourceRange().Ptr(),
})
break
}
remain = remain[1:]
step := ModuleInstanceStep{
Name: moduleName,
}
if len(remain) > 0 {
if idx, ok := remain[0].(hcl.TraverseIndex); ok {
remain = remain[1:]
switch idx.Key.Type() {
case cty.String:
step.InstanceKey = StringKey(idx.Key.AsString())
case cty.Number:
var idxInt int
err := gocty.FromCtyValue(idx.Key, &idxInt)
if err == nil {
step.InstanceKey = IntKey(idxInt)
} else {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid address operator",
Detail: fmt.Sprintf("Invalid module index: %s.", err),
Subject: idx.SourceRange().Ptr(),
})
}
default:
// Should never happen, because no other types are allowed in traversal indices.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid address operator",
Detail: "Invalid module key: must be either a string or an integer.",
Subject: idx.SourceRange().Ptr(),
})
}
}
}
mi = append(mi, step)
}
var retRemain hcl.Traversal
if len(remain) > 0 {
retRemain = make(hcl.Traversal, len(remain))
copy(retRemain, remain)
// The first element here might be either a TraverseRoot or a
// TraverseAttr, depending on whether we had a module address on the
// front. To make life easier for callers, we'll normalize to always
// start with a TraverseRoot.
if tt, ok := retRemain[0].(hcl.TraverseAttr); ok {
retRemain[0] = hcl.TraverseRoot{
Name: tt.Name,
SrcRange: tt.SrcRange,
}
}
}
return mi, retRemain, diags
}
// UnkeyedInstanceShim is a shim method for converting a Module address to the
// equivalent ModuleInstance address that assumes that no modules have
// keyed instances.
//
// This is a temporary allowance for the fact that Terraform does not presently
// support "count" and "for_each" on modules, and thus graph building code that
// derives graph nodes from configuration must just assume unkeyed modules
// in order to construct the graph. At a later time when "count" and "for_each"
// support is added for modules, all callers of this method will need to be
// reworked to allow for keyed module instances.
func (m Module) UnkeyedInstanceShim() ModuleInstance {
path := make(ModuleInstance, len(m))
for i, name := range m {
path[i] = ModuleInstanceStep{Name: name}
}
return path
}
// ModuleInstanceStep is a single traversal step through the dynamic module
// tree. It is used only as part of ModuleInstance.
type ModuleInstanceStep struct {
Name string
InstanceKey InstanceKey
}
// RootModuleInstance is the module instance address representing the root
// module, which is also the zero value of ModuleInstance.
var RootModuleInstance ModuleInstance
// IsRoot returns true if the receiver is the address of the root module instance,
// or false otherwise.
func (m ModuleInstance) IsRoot() bool {
return len(m) == 0
}
// Child returns the address of a child module instance of the receiver,
// identified by the given name and key.
func (m ModuleInstance) Child(name string, key InstanceKey) ModuleInstance {
ret := make(ModuleInstance, 0, len(m)+1)
ret = append(ret, m...)
return append(ret, ModuleInstanceStep{
Name: name,
InstanceKey: key,
})
}
// Parent returns the address of the parent module instance of the receiver, or
// the receiver itself if there is no parent (if it's the root module address).
func (m ModuleInstance) Parent() ModuleInstance {
if len(m) == 0 {
return m
}
return m[:len(m)-1]
}
// String returns a string representation of the receiver, in the format used
// within e.g. user-provided resource addresses.
//
// The address of the root module has the empty string as its representation.
func (m ModuleInstance) String() string {
var buf bytes.Buffer
sep := ""
for _, step := range m {
buf.WriteString(sep)
buf.WriteString("module.")
buf.WriteString(step.Name)
if step.InstanceKey != NoKey {
buf.WriteString(step.InstanceKey.String())
}
sep = "."
}
return buf.String()
}
// Less returns true if the receiver should sort before the given other value
// in a sorted list of addresses.
func (m ModuleInstance) Less(o ModuleInstance) bool {
if len(m) != len(o) {
// Shorter path sorts first.
return len(m) < len(o)
}
for i := range m {
mS, oS := m[i], o[i]
switch {
case mS.Name != oS.Name:
return mS.Name < oS.Name
case mS.InstanceKey != oS.InstanceKey:
return InstanceKeyLess(mS.InstanceKey, oS.InstanceKey)
}
}
return false
}
// Ancestors returns a slice containing the receiver and all of its ancestor
// module instances, all the way up to (and including) the root module.
// The result is ordered by depth, with the root module always first.
//
// Since the result always includes the root module, a caller may choose to
// ignore it by slicing the result with [1:].
func (m ModuleInstance) Ancestors() []ModuleInstance {
ret := make([]ModuleInstance, 0, len(m)+1)
for i := 0; i <= len(m); i++ {
ret = append(ret, m[:i])
}
return ret
}
// Call returns the module call address that corresponds to the given module
// instance, along with the address of the module instance that contains it.
//
// There is no call for the root module, so this method will panic if called
// on the root module address.
//
// A single module call can produce potentially many module instances, so the
// result discards any instance key that might be present on the last step
// of the instance. To retain this, use CallInstance instead.
//
// In practice, this just turns the last element of the receiver into a
// ModuleCall and then returns a slice of the receiever that excludes that
// last part. This is just a convenience for situations where a call address
// is required, such as when dealing with *Reference and Referencable values.
func (m ModuleInstance) Call() (ModuleInstance, ModuleCall) {
if len(m) == 0 {
panic("cannot produce ModuleCall for root module")
}
inst, lastStep := m[:len(m)-1], m[len(m)-1]
return inst, ModuleCall{
Name: lastStep.Name,
}
}
// CallInstance returns the module call instance address that corresponds to
// the given module instance, along with the address of the module instance
// that contains it.
//
// There is no call for the root module, so this method will panic if called
// on the root module address.
//
// In practice, this just turns the last element of the receiver into a
// ModuleCallInstance and then returns a slice of the receiever that excludes
// that last part. This is just a convenience for situations where a call\
// address is required, such as when dealing with *Reference and Referencable
// values.
func (m ModuleInstance) CallInstance() (ModuleInstance, ModuleCallInstance) {
if len(m) == 0 {
panic("cannot produce ModuleCallInstance for root module")
}
inst, lastStep := m[:len(m)-1], m[len(m)-1]
return inst, ModuleCallInstance{
Call: ModuleCall{
Name: lastStep.Name,
},
Key: lastStep.InstanceKey,
}
}
// TargetContains implements Targetable by returning true if the given other
// address either matches the receiver, is a sub-module-instance of the
// receiver, or is a targetable absolute address within a module that
// is contained within the reciever.
func (m ModuleInstance) TargetContains(other Targetable) bool {
switch to := other.(type) {
case ModuleInstance:
if len(to) < len(m) {
// Can't be contained if the path is shorter
return false
}
// Other is contained if its steps match for the length of our own path.
for i, ourStep := range m {
otherStep := to[i]
if ourStep != otherStep {
return false
}
}
// If we fall out here then the prefixed matched, so it's contained.
return true
case AbsResource:
return m.TargetContains(to.Module)
case AbsResourceInstance:
return m.TargetContains(to.Module)
default:
return false
}
}
func (m ModuleInstance) targetableSigil() {
// ModuleInstance is targetable
}