terraform/configs/configupgrade/module_sources.go

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package configupgrade
import (
"fmt"
"io/ioutil"
"path/filepath"
"strings"
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/terraform/configs"
"github.com/hashicorp/terraform/tfdiags"
"github.com/hashicorp/hcl/v2"
hcl2syntax "github.com/hashicorp/hcl/v2/hclsyntax"
version "github.com/hashicorp/go-version"
)
type ModuleSources map[string][]byte
// LoadModule looks for Terraform configuration files in the given directory
// and loads each of them into memory as source code, in preparation for
// further analysis and conversion.
//
// At this stage the files are not parsed at all. Instead, we just read the
// raw bytes from the file so that they can be passed into a parser in a
// separate step.
//
// If the given directory or any of the files cannot be read, an error is
// returned. It is not safe to proceed with processing in that case because
// we cannot "see" all of the source code for the configuration.
func LoadModule(dir string) (ModuleSources, error) {
entries, err := ioutil.ReadDir(dir)
if err != nil {
return nil, err
}
ret := make(ModuleSources)
for _, entry := range entries {
name := entry.Name()
if entry.IsDir() {
continue
}
if configs.IsIgnoredFile(name) {
continue
}
ext := fileExt(name)
if ext == "" {
continue
}
fullPath := filepath.Join(dir, name)
src, err := ioutil.ReadFile(fullPath)
if err != nil {
return nil, err
}
ret[name] = src
}
return ret, nil
}
// UnusedFilename finds a filename that isn't already used by a file in
// the receiving sources and returns it.
//
// The given "proposed" name is returned verbatim if it isn't already used.
// Otherwise, the function will try appending incrementing integers to the
// proposed name until an unused name is found. Callers should propose names
// that they do not expect to already be in use so that numeric suffixes are
// only used in rare cases.
//
// The proposed name must end in either ".tf" or ".tf.json" because a
// ModuleSources only has visibility into such files. This function will
// panic if given a file whose name does not end with one of these
// extensions.
//
// A ModuleSources only works on one directory at a time, so the proposed
// name must not contain any directory separator characters.
func (ms ModuleSources) UnusedFilename(proposed string) string {
ext := fileExt(proposed)
if ext == "" {
panic(fmt.Errorf("method UnusedFilename used with invalid proposal %q", proposed))
}
if _, exists := ms[proposed]; !exists {
return proposed
}
base := proposed[:len(proposed)-len(ext)]
for i := 1; ; i++ {
try := fmt.Sprintf("%s-%d%s", base, i, ext)
if _, exists := ms[try]; !exists {
return try
}
}
}
// MaybeAlreadyUpgraded is a heuristic to see if a given module may have
// already been upgraded by this package.
//
// The heuristic used is to look for a Terraform Core version constraint in
// any of the given sources that seems to be requiring a version greater than
// or equal to v0.12.0. If true is returned then the source range of the found
// version constraint is returned in case the caller wishes to present it to
// the user as context for a warning message. The returned range is not
// meaningful if false is returned.
func (ms ModuleSources) MaybeAlreadyUpgraded() (bool, tfdiags.SourceRange) {
for name, src := range ms {
f, diags := hcl2syntax.ParseConfig(src, name, hcl.Pos{Line: 1, Column: 1})
if diags.HasErrors() {
// If we can't parse at all then that's a reasonable signal that
// we _haven't_ been upgraded yet, but we'll continue checking
// other files anyway.
continue
}
content, _, diags := f.Body.PartialContent(&hcl.BodySchema{
Blocks: []hcl.BlockHeaderSchema{
{
Type: "terraform",
},
},
})
if diags.HasErrors() {
// Suggests that the file has an invalid "terraform" block, such
// as one with labels.
continue
}
for _, block := range content.Blocks {
content, _, diags := block.Body.PartialContent(&hcl.BodySchema{
Attributes: []hcl.AttributeSchema{
{
Name: "required_version",
},
},
})
if diags.HasErrors() {
continue
}
attr, present := content.Attributes["required_version"]
if !present {
continue
}
constraintVal, diags := attr.Expr.Value(nil)
if diags.HasErrors() {
continue
}
if constraintVal.Type() != cty.String || constraintVal.IsNull() {
continue
}
constraints, err := version.NewConstraint(constraintVal.AsString())
if err != nil {
continue
}
// The go-version package doesn't actually let us see the details
// of the parsed constraints here, so we now need a bit of an
// abstraction inversion to decide if any of the given constraints
// match our heuristic. However, we do at least get to benefit
// from go-version's ability to extract multiple constraints from
// a single string and the fact that it's already validated each
// constraint to match its expected pattern.
Constraints:
for _, constraint := range constraints {
str := strings.TrimSpace(constraint.String())
// Want to match >, >= and ~> here.
if !(strings.HasPrefix(str, ">") || strings.HasPrefix(str, "~>")) {
continue
}
// Try to find something in this string that'll parse as a version.
for i := 1; i < len(str); i++ {
candidate := str[i:]
v, err := version.NewVersion(candidate)
if err != nil {
continue
}
if v.Equal(firstVersionWithNewParser) || v.GreaterThan(firstVersionWithNewParser) {
// This constraint appears to be preventing the old
// parser from being used, so we suspect it was
// already upgraded.
return true, tfdiags.SourceRangeFromHCL(attr.Range)
}
// If we fall out here then we _did_ find something that
// parses as a version, so we'll stop and move on to the
// next constraint. (Otherwise we'll pass by 0.7.0 and find
// 7.0, which is also a valid version.)
continue Constraints
}
}
}
}
return false, tfdiags.SourceRange{}
}
var firstVersionWithNewParser = version.Must(version.NewVersion("0.12.0"))
// fileExt returns the Terraform configuration extension of the given
// path, or a blank string if it is not a recognized extension.
func fileExt(path string) string {
if strings.HasSuffix(path, ".tf") {
return ".tf"
} else if strings.HasSuffix(path, ".tf.json") {
return ".tf.json"
} else {
return ""
}
}