terraform/configs/configupgrade/upgrade_expr.go

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package configupgrade
import (
"bytes"
"fmt"
"strconv"
hcl2 "github.com/hashicorp/hcl2/hcl"
hcl1ast "github.com/hashicorp/hcl/hcl/ast"
hcl1printer "github.com/hashicorp/hcl/hcl/printer"
hcl1token "github.com/hashicorp/hcl/hcl/token"
"github.com/hashicorp/hil"
hilast "github.com/hashicorp/hil/ast"
"github.com/hashicorp/terraform/tfdiags"
)
func upgradeExpr(val interface{}, filename string, interp bool, an *analysis) ([]byte, tfdiags.Diagnostics) {
var buf bytes.Buffer
var diags tfdiags.Diagnostics
// "val" here can be either a hcl1ast.Node or a hilast.Node, since both
// of these correspond to expressions in HCL2. Therefore we need to
// comprehensively handle every possible HCL1 *and* HIL AST node type
// and, at minimum, print it out as-is in HCL2 syntax.
switch tv := val.(type) {
case *hcl1ast.LiteralType:
litVal := tv.Token.Value()
switch tv.Token.Type {
case hcl1token.STRING:
if !interp {
// Easy case, then.
printQuotedString(&buf, litVal.(string))
break
}
hilNode, err := hil.Parse(litVal.(string))
if err != nil {
diags = diags.Append(&hcl2.Diagnostic{
Severity: hcl2.DiagError,
Summary: "Invalid interpolated string",
Detail: fmt.Sprintf("Interpolation parsing failed: %s", err),
Subject: hcl1PosRange(filename, tv.Pos()).Ptr(),
})
}
interpSrc, interpDiags := upgradeExpr(hilNode, filename, interp, an)
buf.Write(interpSrc)
diags = diags.Append(interpDiags)
case hcl1token.HEREDOC:
// TODO: Implement
panic("HEREDOC not supported yet")
case hcl1token.BOOL:
if litVal.(bool) {
buf.WriteString("true")
} else {
buf.WriteString("false")
}
default:
// For everything else (NUMBER, FLOAT) we'll just pass through the given bytes verbatim.
buf.WriteString(tv.Token.Text)
}
case hcl1ast.Node:
// If our more-specific cases above didn't match this then we'll
// ask the hcl1printer package to print the expression out
// itself, and assume it'll still be valid in HCL2.
// (We should rarely end up here, since our cases above should
// be comprehensive.)
hcl1printer.Fprint(&buf, tv)
case *hilast.LiteralNode:
switch tl := tv.Value.(type) {
case string:
// This shouldn't generally happen because literal strings are
// always wrapped in hilast.Output in HIL, but we'll allow it anyway.
printQuotedString(&buf, tl)
case int:
buf.WriteString(strconv.Itoa(tl))
case float64:
buf.WriteString(strconv.FormatFloat(tl, 'f', 64, 64))
case bool:
if tl {
buf.WriteString("true")
} else {
buf.WriteString("false")
}
}
case *hilast.VariableAccess:
buf.WriteString(tv.Name)
case *hilast.Arithmetic:
op, exists := hilArithmeticOpSyms[tv.Op]
if !exists {
panic(fmt.Errorf("arithmetic node with unsupported operator %#v", tv.Op))
}
lhsExpr := tv.Exprs[0]
rhsExpr := tv.Exprs[1]
lhsSrc, exprDiags := upgradeExpr(lhsExpr, filename, true, an)
diags = diags.Append(exprDiags)
rhsSrc, exprDiags := upgradeExpr(rhsExpr, filename, true, an)
diags = diags.Append(exprDiags)
// HIL's AST represents -foo as (0 - foo), so we'll recognize
// that here and normalize it back.
if tv.Op == hilast.ArithmeticOpSub && len(lhsSrc) == 1 && lhsSrc[0] == '0' {
buf.WriteString("-")
buf.Write(rhsSrc)
break
}
buf.Write(lhsSrc)
buf.WriteString(op)
buf.Write(rhsSrc)
case *hilast.Call:
name := tv.Func
args := tv.Args
buf.WriteString(name)
buf.WriteByte('(')
for i, arg := range args {
if i > 0 {
buf.WriteString(", ")
}
exprSrc, exprDiags := upgradeExpr(arg, filename, true, an)
diags = diags.Append(exprDiags)
buf.Write(exprSrc)
}
buf.WriteByte(')')
case *hilast.Conditional:
condSrc, exprDiags := upgradeExpr(tv.CondExpr, filename, true, an)
diags = diags.Append(exprDiags)
trueSrc, exprDiags := upgradeExpr(tv.TrueExpr, filename, true, an)
diags = diags.Append(exprDiags)
falseSrc, exprDiags := upgradeExpr(tv.FalseExpr, filename, true, an)
diags = diags.Append(exprDiags)
buf.Write(condSrc)
buf.WriteString(" ? ")
buf.Write(trueSrc)
buf.WriteString(" : ")
buf.Write(falseSrc)
case *hilast.Index:
targetSrc, exprDiags := upgradeExpr(tv.Target, filename, true, an)
diags = diags.Append(exprDiags)
keySrc, exprDiags := upgradeExpr(tv.Key, filename, true, an)
diags = diags.Append(exprDiags)
buf.Write(targetSrc)
buf.WriteString("[")
buf.Write(keySrc)
buf.WriteString("]")
case *hilast.Output:
if len(tv.Exprs) == 1 {
item := tv.Exprs[0]
naked := true
if lit, ok := item.(*hilast.LiteralNode); ok {
if _, ok := lit.Value.(string); ok {
naked = false
}
}
if naked {
// If there's only one expression and it isn't a literal string
// then we'll just output it naked, since wrapping a single
// expression in interpolation is no longer idiomatic.
interped, interpDiags := upgradeExpr(item, filename, true, an)
diags = diags.Append(interpDiags)
buf.Write(interped)
break
}
}
buf.WriteString(`"`)
for _, item := range tv.Exprs {
if lit, ok := item.(*hilast.LiteralNode); ok {
if litStr, ok := lit.Value.(string); ok {
printStringLiteralFromHILOutput(&buf, litStr)
continue
}
}
interped, interpDiags := upgradeExpr(item, filename, true, an)
diags = diags.Append(interpDiags)
buf.WriteString("${")
buf.Write(interped)
buf.WriteString("}")
}
buf.WriteString(`"`)
case hilast.Node:
// Nothing reasonable we can do here, so we should've handled all of
// the possibilities above.
panic(fmt.Errorf("upgradeExpr doesn't handle HIL node type %T", tv))
default:
// If we end up in here then the caller gave us something completely invalid.
panic(fmt.Errorf("upgradeExpr on unsupported type %T", val))
}
return buf.Bytes(), diags
}
var hilArithmeticOpSyms = map[hilast.ArithmeticOp]string{
hilast.ArithmeticOpAdd: " + ",
hilast.ArithmeticOpSub: " - ",
hilast.ArithmeticOpMul: " * ",
hilast.ArithmeticOpDiv: " / ",
hilast.ArithmeticOpMod: " % ",
hilast.ArithmeticOpLogicalAnd: " && ",
hilast.ArithmeticOpLogicalOr: " || ",
hilast.ArithmeticOpEqual: " == ",
hilast.ArithmeticOpNotEqual: " != ",
hilast.ArithmeticOpLessThan: " < ",
hilast.ArithmeticOpLessThanOrEqual: " <= ",
hilast.ArithmeticOpGreaterThan: " > ",
hilast.ArithmeticOpGreaterThanOrEqual: " >= ",
}