Go toolchain "caster"

go.mod

@@ -4,6 +4,7 @@ go 1.15
 
 require (
 	github.com/Masterminds/semver/v3 v3.1.0
+	github.com/magefile/mage v1.10.0
 	github.com/stretchr/testify v1.6.1
 	github.com/svengreb/golib v0.1.0
 )

go.sum

@@ -38,6 +38,8 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/magefile/mage v1.10.0 h1:3HiXzCUY12kh9bIuyXShaVe529fJfyqoVM42o/uom2g=
+github.com/magefile/mage v1.10.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=

internal/support/os/env.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+// Package os provides utilities for operating system related operations and interactions.
+package os
+
+import (
+	"fmt"
+	"strings"
+)
+
+// EnvMapToSlice transforms a map of environment variable key/value pairs into a slice separated by an equal sign.
+func EnvMapToSlice(src map[string]string) []string {
+	dst := make([]string, len(src))
+	for k, v := range src {
+		dst = append(dst, fmt.Sprintf("%s=%s", k, v))
+	}
+	return dst
+}
+
+// EnvSliceToMap transforms a slice of environment variables separated by an equal sign into a map.
+func EnvSliceToMap(src []string, dst map[string]string) {
+	for _, envVar := range src {
+		kv := strings.Split(envVar, "=")
+		if len(kv) == 1 {
+			dst[kv[0]] = ""
+		} else {
+			dst[kv[0]] = kv[1]
+		}
+	}
+}

pkg/cast/cast.go

@@ -1,6 +1,7 @@
 // Copyright (c) 2019-present Sven Greb <development@svengreb.de>
 // This source code is licensed under the MIT license found in the LICENSE file.
 
+// Package cast provides caster for spell incantations.
 package cast
 
 import (

pkg/cast/error.go

@@ -0,0 +1,47 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+package cast
+
+import (
+	"errors"
+	"fmt"
+
+	wErr "github.com/svengreb/wand/pkg/error"
+)
+
+const (
+	// ErrCasterValidation indicates that a caster validation failed.
+	ErrCasterValidation = wErr.ErrString("caster validation failed")
+
+	// ErrCasterSpellIncantationKindUnsupported indicates that a spell incantation kind is not supported by a caster.
+	ErrCasterSpellIncantationKindUnsupported = wErr.ErrString("unsupported spell incantation kind")
+)
+
+// ErrCast represents a cast error.
+type ErrCast struct {
+	// Err is a wrapped error.
+	Err error
+	// Kind is the error kind.
+	Kind error
+}
+
+func (e *ErrCast) Error() string {
+	msg := "cast error"
+	if e.Kind != nil {
+		msg = fmt.Sprintf("%s: %v", msg, e.Kind)
+	}
+	if e.Err != nil {
+		msg = fmt.Sprintf("%s: %v", msg, e.Err)
+	}
+
+	return msg
+}
+
+// Is enables usage of errors.Is() to determine the kind of error that occurred.
+func (e *ErrCast) Is(err error) bool {
+	return errors.Is(err, e.Kind)
+}
+
+// Unwrap returns the underlying error for usage with errors.Unwrap().
+func (e *ErrCast) Unwrap() error { return e.Err }

pkg/cast/golang/toolchain/options.go

@@ -0,0 +1,64 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+package toolchain
+
+import (
+	"github.com/magefile/mage/mg"
+)
+
+const (
+	// CasterName is the name of the Go toolchain command caster.
+	CasterName = "golang"
+
+	// DefaultEnvVarGO111MODULE is the default environment variable name to toggle the Go 1.11 module mode.
+	DefaultEnvVarGO111MODULE = "GO111MODULE"
+
+	// DefaultEnvVarGOBIN is the default environment variable name for the Go binary executable path.
+	DefaultEnvVarGOBIN = "GOBIN"
+
+	// DefaultEnvVarGOFLAGS is the default environment variable name for Go tool flags.
+	DefaultEnvVarGOFLAGS = "GOFLAGS"
+
+	// DefaultEnvVarGOPATH is the default environment variable name for the Go path.
+	DefaultEnvVarGOPATH = "GOPATH"
+)
+
+// DefaultExec is the default path to the Go executable.
+var DefaultExec = mg.GoCmd()
+
+// Options stores Go toolchain command caster options.
+type Options struct {
+	Env  map[string]string
+	Exec string
+}
+
+// Option is a Go toolchain command caster option.
+type Option func(*Options)
+
+// WithEnv sets the caster environment.
+func WithEnv(env map[string]string) Option {
+	return func(o *Options) {
+		o.Env = env
+	}
+}
+
+// WithExec sets the path to the Go executable.
+func WithExec(nameOrPath string) Option {
+	return func(o *Options) {
+		o.Exec = nameOrPath
+	}
+}
+
+// newOptions creates new Go toolchain command caster options.
+func newOptions(opts ...Option) *Options {
+	opt := &Options{
+		Env:  make(map[string]string),
+		Exec: DefaultExec,
+	}
+	for _, o := range opts {
+		o(opt)
+	}
+
+	return opt
+}

pkg/cast/golang/toolchain/toolchain.go

@@ -0,0 +1,89 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+package toolchain
+
+import (
+	"fmt"
+	"os/exec"
+
+	"github.com/magefile/mage/sh"
+	glFS "github.com/svengreb/golib/pkg/io/fs"
+
+	"github.com/svengreb/wand/pkg/cast"
+	"github.com/svengreb/wand/pkg/spell"
+)
+
+// Caster is a Go toolchain command caster.
+type Caster struct {
+	opts *Options
+}
+
+// GetExec returns the path to the binary executable.
+func (c *Caster) GetExec() string {
+	return c.opts.Exec
+}
+
+// Cast casts a spell incantation.
+// It returns an error of type *cast.ErrCast when the spell is not a spell.KindBinary and any other error that occurs
+// during the command execution.
+func (c *Caster) Cast(si spell.Incantation) error {
+	if si.Kind() != spell.KindBinary {
+		return &cast.ErrCast{
+			Err:  fmt.Errorf("%q", si.Kind()),
+			Kind: cast.ErrCasterSpellIncantationKindUnsupported,
+		}
+	}
+
+	s, ok := si.(spell.Binary)
+	if !ok {
+		return &cast.ErrCast{
+			Err:  fmt.Errorf("expected %q but got %q", s.Kind(), si.Kind()),
+			Kind: cast.ErrCasterSpellIncantationKindUnsupported,
+		}
+	}
+
+	args := si.Formula()
+	for k, v := range s.Env() {
+		c.opts.Env[k] = v
+	}
+
+	return sh.RunWithV(c.opts.Env, c.opts.Exec, args...)
+}
+
+// Handles returns the supported spell.Kind.
+func (c *Caster) Handles() spell.Kind {
+	return spell.KindBinary
+}
+
+// Validate validates the Go toolchain command caster.
+// It returns an error of type *cast.ErrCast when the binary executable does not exists at the configured path and when
+// it is also not available in the executable search paths of the current environment.
+func (c *Caster) Validate() error {
+	// Check if the Go executable exists,...
+	execExits, fsErr := glFS.FileExists(c.opts.Exec)
+	if fsErr != nil {
+		return &cast.ErrCast{
+			Err:  fmt.Errorf("caster %q: %w", CasterName, fsErr),
+			Kind: cast.ErrCasterValidation,
+		}
+	}
+	// ...otherwise try to look up the system-wide executable paths.
+	if !execExits {
+		path, pathErr := exec.LookPath(c.opts.Exec)
+		if pathErr != nil {
+			return &cast.ErrCast{
+				Err:  fmt.Errorf("caster %q: %q not found or does not exist: %w", CasterName, c.opts.Exec, pathErr),
+				Kind: cast.ErrCasterValidation,
+			}
+		}
+		c.opts.Exec = path
+	}
+
+	return nil
+}
+
+// NewCaster creates a new Go toolchain command caster.
+func NewCaster(opts ...Option) *Caster {
+	return &Caster{opts: newOptions(opts...)}
+}

pkg/error/error.go

@@ -0,0 +1,12 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+// Package error provides types and utilities to handle errors.
+package error
+
+// ErrString is a string type for implementing constant errors.
+type ErrString string
+
+func (e ErrString) Error() string {
+	return string(e)
+}

pkg/project/error.go

@@ -6,29 +6,24 @@ package project
 import (
 	"errors"
 	"fmt"
+
+	wErr "github.com/svengreb/wand/pkg/error"
 )
 
 const (
 	// ErrDeriveVCSInformation indicates that the derivation of VCS version information failed.
-	ErrDeriveVCSInformation = ErrString("failed to derive VCS version information")
+	ErrDeriveVCSInformation = wErr.ErrString("failed to derive VCS version information")
 
 	// ErrDetectProjectRootDirPath indicates that the detection of a project root directory path failed.
-	ErrDetectProjectRootDirPath = ErrString("failed to detect project root directory path")
+	ErrDetectProjectRootDirPath = wErr.ErrString("failed to detect project root directory path")
 
 	// ErrDetermineGoModuleInformation indicates that a determination of Go module information failed.
-	ErrDetermineGoModuleInformation = ErrString("failed to determine Go module information")
+	ErrDetermineGoModuleInformation = wErr.ErrString("failed to determine Go module information")
 
-	// ErrPathNotRelative indicates that a path is not releative.
-	ErrPathNotRelative = ErrString("path is not relative")
+	// ErrPathNotRelative indicates that a path is not relative.
+	ErrPathNotRelative = wErr.ErrString("path is not relative")
 )
 
-// ErrString is a string type for implementing constant errors.
-type ErrString string
-
-func (e ErrString) Error() string {
-	return string(e)
-}
-
 // ErrProject represents a project error.
 type ErrProject struct {
 	// Err is a wrapped error.

pkg/project/vcs/doc.go

@@ -0,0 +1,6 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+// Package vcs provides packages utilities to interact with version control systems.
+// See https://en.wikipedia.org/wiki/Version_control for more details about VCS.
+package vcs

pkg/project/vcs/git/git.go

@@ -1,6 +1,8 @@
 // Copyright (c) 2019-present Sven Greb <development@svengreb.de>
 // This source code is licensed under the MIT license found in the LICENSE file.
 
+// Package git provides VCS utility functions to interact with Git repositories.
+// See https://git-scm.com for more details about Git.
 package git
 
 import (

pkg/spell/spell.go

@@ -1,6 +1,7 @@
 // Copyright (c) 2019-present Sven Greb <development@svengreb.de>
 // This source code is licensed under the MIT license found in the LICENSE file.
 
+// Package spell provides incantations for different kinds.
 package spell
 
 import "github.com/svengreb/wand/pkg/project"