get builds from PackerConfig instead of parser

to allow just reading the config and to not start anything. This will allow to later on run `validate --syntax-only`.

Note that none of the builder/provisioner/post-processor config will be read but simply ignored. HCL2 still needs the body to be properly formatted and it should detect most syntax errors.

command/build.go

@@ -104,7 +104,7 @@ func (c *BuildCommand) GetBuildsFromHCL(path string) ([]packer.Build, int) {
 		PostProcessorsSchemas: c.CoreConfig.Components.PostProcessorStore,
 	}
 
-	builds, diags := parser.Parse(path, c.varFiles, c.flagVars, c.CoreConfig.Only, c.CoreConfig.Except)
+	cfg, diags := parser.Parse(path, c.varFiles, c.flagVars)
 	{
 		// write HCL errors/diagnostics if any.
 		b := bytes.NewBuffer(nil)
@@ -122,6 +122,24 @@ func (c *BuildCommand) GetBuildsFromHCL(path string) ([]packer.Build, int) {
 		ret = 1
 	}
 
+	builds, diags := cfg.GetBuilds(c.CoreConfig.Only, c.CoreConfig.Except)
+	{
+		// write HCL errors/diagnostics if any.
+		b := bytes.NewBuffer(nil)
+		err := hcl.NewDiagnosticTextWriter(b, parser.Files(), 80, false).WriteDiagnostics(diags)
+		if err != nil {
+			c.Ui.Error("could not write diagnostic: " + err.Error())
+			return nil, 1
+		}
+		if b.Len() != 0 {
+			c.Ui.Message(b.String())
+		}
+	}
+	ret = 0
+	if diags.HasErrors() {
+		ret = 1
+	}
+
 	return builds, ret
 }
 

hcl2template/common_test.go

@@ -59,7 +59,7 @@ func testParse(t *testing.T, tests []parseTest) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			gotCfg, gotDiags := tt.parser.parse(tt.args.filename, tt.args.varFiles, tt.args.vars)
+			gotCfg, gotDiags := tt.parser.Parse(tt.args.filename, tt.args.varFiles, tt.args.vars)
 			if tt.parseWantDiags == (gotDiags == nil) {
 				t.Fatalf("Parser.parse() unexpected %q diagnostics.", gotDiags)
 			}
@@ -116,7 +116,7 @@ func testParse(t *testing.T, tests []parseTest) {
 				return
 			}
 
-			gotBuilds, gotDiags := gotCfg.getBuilds(nil, nil)
+			gotBuilds, gotDiags := gotCfg.GetBuilds(nil, nil)
 			if tt.getBuildsWantDiags == (gotDiags == nil) {
 				t.Fatalf("Parser.getBuilds() unexpected diagnostics. %s", gotDiags)
 			}

hcl2template/parser.go

@@ -52,7 +52,11 @@ const (
 	hcl2VarJsonFileExt = ".auto.pkrvars.json"
 )
 
-func (p *Parser) parse(filename string, varFiles []string, argVars map[string]string) (*PackerConfig, hcl.Diagnostics) {
+// Parse will Parse HCL file(s) in path. Path can be a folder or a file.
+//
+// Parse will first Parse variables and then the rest; so that interpolation
+// can happen.
+func (p *Parser) Parse(filename string, varFiles []string, argVars map[string]string) (*PackerConfig, hcl.Diagnostics) {
 
 	var files []*hcl.File
 	var diags hcl.Diagnostics

hcl2template/types.packer_config.go

@@ -7,8 +7,6 @@ import (
 	"github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 	"github.com/zclconf/go-cty/cty"
-
-	"github.com/gobwas/glob"
 )
 
 // PackerConfig represents a loaded Packer HCL config. It will contain
@@ -253,10 +251,10 @@ func (cfg *PackerConfig) getCoreBuildPostProcessors(source *SourceBlock, blocks
 	return res, diags
 }
 
-// getBuilds will return a list of packer Build based on the HCL2 parsed build
+// GetBuilds returns a list of packer Build based on the HCL2 parsed build
 // blocks. All Builders, Provisioners and Post Processors will be started and
 // configured.
-func (cfg *PackerConfig) getBuilds(onlyGlobs []glob.Glob, exceptGlobs []glob.Glob) ([]packer.Build, hcl.Diagnostics) {
+func (cfg *PackerConfig) GetBuilds(only, except []string) ([]packer.Build, hcl.Diagnostics) {
 	res := []packer.Build{}
 	var diags hcl.Diagnostics
 
@@ -276,7 +274,11 @@ func (cfg *PackerConfig) getBuilds(onlyGlobs []glob.Glob, exceptGlobs []glob.Glo
 			buildName := fmt.Sprintf("%s.%s", src.Type, src.Name)
 
 			// -only
-			if len(onlyGlobs) > 0 {
+			if len(only) > 0 {
+				onlyGlobs, diags := convertFilterOption(only, "only")
+				if diags.HasErrors() {
+					return nil, diags
+				}
 				include := false
 				for _, onlyGlob := range onlyGlobs {
 					if onlyGlob.Match(buildName) {
@@ -290,7 +292,11 @@ func (cfg *PackerConfig) getBuilds(onlyGlobs []glob.Glob, exceptGlobs []glob.Glo
 			}
 
 			// -except
-			if len(exceptGlobs) > 0 {
+			if len(except) > 0 {
+				exceptGlobs, diags := convertFilterOption(except, "except")
+				if diags.HasErrors() {
+					return nil, diags
+				}
 				exclude := false
 				for _, exceptGlob := range exceptGlobs {
 					if exceptGlob.Match(buildName) {
@@ -356,60 +362,3 @@ func (cfg *PackerConfig) getBuilds(onlyGlobs []glob.Glob, exceptGlobs []glob.Glo
 	}
 	return res, diags
 }
-
-// Convert -only and -except globs to glob.Glob instances.
-func convertFilterOption(patterns []string, optionName string) ([]glob.Glob, hcl.Diagnostics) {
-	var globs []glob.Glob
-	var diags hcl.Diagnostics
-
-	for _, pattern := range patterns {
-		g, err := glob.Compile(pattern)
-		if err != nil {
-			diags = append(diags, &hcl.Diagnostic{
-				Summary:  fmt.Sprintf("Invalid -%s pattern %s: %s", optionName, pattern, err),
-				Severity: hcl.DiagError,
-			})
-		}
-		globs = append(globs, g)
-	}
-
-	return globs, diags
-}
-
-// Parse will parse HCL file(s) in path. Path can be a folder or a file.
-//
-// Parse will first parse variables and then the rest; so that interpolation
-// can happen.
-//
-// For each build block a packer.Build will be started, and for each builder,
-// all provisioners and post-processors will be started.
-//
-// Parse then return a slice of packer.Builds; which are what packer core uses
-// to run builds.
-func (p *Parser) Parse(path string, varFiles []string, argVars map[string]string, onlyBuilds []string, exceptBuilds []string) ([]packer.Build, hcl.Diagnostics) {
-	var onlyGlobs []glob.Glob
-	if len(onlyBuilds) > 0 {
-		og, diags := convertFilterOption(onlyBuilds, "only")
-		if diags.HasErrors() {
-			return nil, diags
-		}
-		onlyGlobs = og
-	}
-
-	var exceptGlobs []glob.Glob
-	if len(exceptBuilds) > 0 {
-		eg, diags := convertFilterOption(exceptBuilds, "except")
-		if diags.HasErrors() {
-			return nil, diags
-		}
-		exceptGlobs = eg
-	}
-
-	cfg, diags := p.parse(path, varFiles, argVars)
-	if diags.HasErrors() {
-		return nil, diags
-	}
-
-	builds, moreDiags := cfg.getBuilds(onlyGlobs, exceptGlobs)
-	return builds, append(diags, moreDiags...)
-}

hcl2template/utils.go

@@ -1,11 +1,13 @@
 package hcl2template
 
 import (
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
 
+	"github.com/gobwas/glob"
 	"github.com/hashicorp/hcl/v2"
 )
 
@@ -88,3 +90,22 @@ func GetHCL2Files(filename, hclSuffix, jsonSuffix string) (hclFiles, jsonFiles [
 
 	return hclFiles, jsonFiles, diags
 }
+
+// Convert -only and -except globs to glob.Glob instances.
+func convertFilterOption(patterns []string, optionName string) ([]glob.Glob, hcl.Diagnostics) {
+	var globs []glob.Glob
+	var diags hcl.Diagnostics
+
+	for _, pattern := range patterns {
+		g, err := glob.Compile(pattern)
+		if err != nil {
+			diags = append(diags, &hcl.Diagnostic{
+				Summary:  fmt.Sprintf("Invalid -%s pattern %s: %s", optionName, pattern, err),
+				Severity: hcl.DiagError,
+			})
+		}
+		globs = append(globs, g)
+	}
+
+	return globs, diags
+}