feat: add support for hcl files

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 - Add support for TOML configuration files
+- Add support for HCL configuration files
 - Use stdlib for tests instead of convey
 - Update golangci-lint configuration
 

adapters.go

@@ -2,9 +2,14 @@ package conf
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strings"
 
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/hcl/v2/gohcl"
+	"github.com/hashicorp/hcl/v2/hclsimple"
+	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/pelletier/go-toml/v2"
 )
 
@@ -14,6 +19,7 @@ const (
 	typeInvalid filetype = iota
 	typeJSON
 	typeTOML
+	typeHCL
 )
 
 // getType returns the type of the config file.
@@ -23,18 +29,24 @@ func getType(filename string) filetype {
 		return typeJSON
 	case strings.HasSuffix(filename, ".toml"):
 		return typeTOML
+	case strings.HasSuffix(filename, ".hcl"):
+		return typeHCL
 	default:
 		return typeInvalid
 	}
 }
 
 // unmarshal unmarshals the given data to the given struct.
-func unmarshal(ft filetype, data []byte, v any) error {
+func unmarshal(filepath string, data []byte, v any) error {
+	ft := getType(filepath)
+
 	switch ft {
 	case typeJSON:
 		return unmarshalJSON(data, v)
 	case typeTOML:
 		return unmarshalTOML(data, v)
+	case typeHCL:
+		return unmarshalHCL(filepath, data, v)
 	default:
 		return ErrUnsupportedFileType
 	}
@@ -47,6 +59,8 @@ func marshal(ft filetype, v any) ([]byte, error) {
 		return marshalJSON(v)
 	case typeTOML:
 		return marshalTOML(v)
+	case typeHCL:
+		return marshalHCL(v)
 	default:
 		return nil, ErrUnsupportedFileType
 	}
@@ -91,3 +105,43 @@ func marshalTOML(v any) ([]byte, error) {
 
 	return data, nil
 }
+
+// unmarshalHCL unmarshals the given data to the given struct.
+func unmarshalHCL(filepath string, data []byte, v any) error {
+	err := hclsimple.Decode(filepath, data, nil, v)
+
+	var diags hcl.Diagnostics
+
+	errors.As(err, &diags)
+	newDiags := hclFilterDiagnostics(diags)
+
+	if len(newDiags) > 0 {
+		return fmt.Errorf("cannot parse config file: %w", newDiags)
+	}
+
+	return nil
+}
+
+// marshalHCL marshals the given struct to bytes.
+func marshalHCL(v any) (b []byte, err error) { //nolint:nonamedreturns // need named return to convert a panic to error
+	f := hclwrite.NewEmptyFile()
+	gohcl.EncodeIntoBody(v, f.Body())
+
+	return f.Bytes(), nil
+}
+
+func hclFilterDiagnostics(diags hcl.Diagnostics) hcl.Diagnostics {
+	var newDiags hcl.Diagnostics
+
+	for _, diag := range diags {
+		if diag.Summary != "Unsupported argument" {
+			newDiags = append(newDiags, diag)
+		}
+	}
+
+	if len(newDiags) > 0 {
+		return newDiags
+	}
+
+	return nil
+}

config.go

@@ -7,6 +7,7 @@
 //
 // - JSON: ".json"
 // - TOML: ".toml"
+// - HCL: ".hcl"
 package conf
 
 import (
@@ -89,7 +90,7 @@ func read(path string, data any) error {
 		return fmt.Errorf("cannot read config file: %w", err)
 	}
 
-	return unmarshal(getType(path), content, data)
+	return unmarshal(path, content, data)
 }
 
 func write(path string, data any) error {

config_test.go

@@ -23,6 +23,12 @@ func TestTOMLFiles(t *testing.T) {
 	runTestSuite(t, "toml")
 }
 
+func TestHCLFiles(t *testing.T) {
+	t.Parallel()
+
+	runTestSuite(t, "hcl")
+}
+
 func TestUnknownFiles(t *testing.T) {
 	t.Parallel()
 
@@ -75,9 +81,9 @@ func runTestSuite(t *testing.T, ext string) {
 
 type testconf struct {
 	inUpdate  func()
-	String    string
+	String    string `hcl:"String,optional"`
-	Invariant string
+	Invariant string `hcl:"Invariant,optional"`
-	Int       int
+	Int       int    `hcl:"Int,optional"`
 }
 
 func (t testconf) Update() {

go.mod

@@ -10,7 +10,18 @@ require (
 )
 
 require (
+	github.com/agext/levenshtein v1.2.1 // indirect
+	github.com/apparentlymart/go-textseg/v13 v13.0.0 // indirect
+	github.com/apparentlymart/go-textseg/v15 v15.0.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
+	github.com/hashicorp/hcl/v2 v2.23.0 // indirect
+	github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/zclconf/go-cty v1.13.0 // indirect
+	golang.org/x/mod v0.8.0 // indirect
+	golang.org/x/sys v0.5.0 // indirect
+	golang.org/x/text v0.11.0 // indirect
+	golang.org/x/tools v0.6.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,11 +1,33 @@
+github.com/agext/levenshtein v1.2.1 h1:QmvMAjj2aEICytGiWzmxoE0x2KZvE0fvmqMOfy2tjT8=
+github.com/agext/levenshtein v1.2.1/go.mod h1:JEDfjyjHDjOF/1e4FlBE/PkbqA9OfWu2ki2W0IB5558=
+github.com/apparentlymart/go-textseg/v13 v13.0.0 h1:Y+KvPE1NYz0xl601PVImeQfFyEy6iT90AvPUL1NNfNw=
+github.com/apparentlymart/go-textseg/v13 v13.0.0/go.mod h1:ZK2fH7c4NqDTLtiYLvIkEghdlcqw7yxLeM89kiTRPUo=
+github.com/apparentlymart/go-textseg/v15 v15.0.0 h1:uYvfpb3DyLSCGWnctWKGj857c6ew1u1fNQOlOtuGxQY=
+github.com/apparentlymart/go-textseg/v15 v15.0.0/go.mod h1:K8XmNZdhEBkdlyDdvbmmsvpAG721bKi0joRfFdHIWJ4=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/hashicorp/hcl/v2 v2.23.0 h1:Fphj1/gCylPxHutVSEOf2fBOh1VE4AuLV7+kbJf3qos=
+github.com/hashicorp/hcl/v2 v2.23.0/go.mod h1:62ZYHrXgPoX8xBnzl8QzbWq4dyDsDtfCRgIq1rbJEvA=
+github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 h1:DpOJ2HYzCv8LZP15IdmG+YdwD2luVPHITV96TkirNBM=
+github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
 github.com/pelletier/go-toml/v2 v2.2.3 h1:YmeHyLY8mFWbdkNWwpr+qIL2bEqT0o95WSdkNHvL12M=
 github.com/pelletier/go-toml/v2 v2.2.3/go.mod h1:MfCQTFTvCcUyyvvwm1+G6H/jORL20Xlb6rzQu9GuUkc=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/zclconf/go-cty v1.13.0 h1:It5dfKTTZHe9aeppbNOda3mN7Ag7sg6QkBNm6TkyFa0=
+github.com/zclconf/go-cty v1.13.0/go.mod h1:YKQzy/7pZ7iq2jNFzy5go57xdxdWoLLpaEp4u238AE0=
+golang.org/x/mod v0.8.0 h1:LUYupSeNrTNCGzR/hVBk2NHZO4hXcVaW1k4Qx7rjPx8=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/text v0.11.0 h1:LAntKIrcmeSKERyiOh0XMV39LXS8IE9UL2yP7+f5ij4=
+golang.org/x/text v0.11.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/tools v0.6.0 h1:BOw41kyTf3PuCW1pVQf8+Cyg8pMlkYB1oo9iJ6D/lKM=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

test_data/full.hcl

@@ -0,0 +1,3 @@
+String    = "default string"
+Invariant = "should not change"
+Int       = 1

test_data/invalid.hcl

@@ -0,0 +1 @@
+String: not hcl

test_data/part1.hcl

@@ -0,0 +1 @@
+String = "foo"

test_data/part2.hcl

@@ -0,0 +1 @@
+Int = 42

test_data/same1.hcl

@@ -0,0 +1 @@
+String = "foo"

test_data/same2.hcl

@@ -0,0 +1 @@
+String = "bar"

test_data/unknown.hcl

@@ -0,0 +1,3 @@
+String = "config string"
+Int = 42
+Unknown = "foo"

test_data/valid.hcl

@@ -0,0 +1,2 @@
+String = "config string"
+Int = 42