migrate cross build target from bash script to mage

.travis.yml

@@ -9,7 +9,7 @@ os: linux
 install:
   - ./travis/install.sh
 script:
-  - ./travis/cross_build.sh
+  - go run mage.go -v crossBuild
   - ./travis/lint.sh
   - export GOMAXPROCS=4
   - export GORACE=halt_on_error=1

go.mod

@@ -2,6 +2,7 @@ module github.com/sirupsen/logrus
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/magefile/mage v1.10.0
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/stretchr/testify v1.2.2
 	golang.org/x/sys v0.0.0-20191026070338-33540a1f6037

go.sum

@@ -1,5 +1,7 @@
 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/magefile/mage v1.10.0 h1:3HiXzCUY12kh9bIuyXShaVe529fJfyqoVM42o/uom2g=
+github.com/magefile/mage v1.10.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=
 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 v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=

mage.go

@@ -0,0 +1,10 @@
+// +build ignore
+
+package main
+
+import (
+	"github.com/magefile/mage/mage"
+	"os"
+)
+
+func main() { os.Exit(mage.Main()) }

magefile.go

@@ -0,0 +1,60 @@
+// +build mage
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/magefile/mage/mg"
+	"github.com/magefile/mage/sh"
+)
+
+// GenBuildMatrix regenerates the build matrix from the current version of the go compiler
+func getBuildMatrix() (map[string][]string, error) {
+	jsonData, err := sh.Output("go", "tool", "dist", "list", "-json")
+	if err != nil {
+		return nil, err
+	}
+	var data []struct {
+		Goos   string
+		Goarch string
+	}
+	if err := json.Unmarshal([]byte(jsonData), &data); err != nil {
+		return nil, err
+	}
+
+	matrix := map[string][]string{}
+	for _, v := range data {
+		if val, ok := matrix[v.Goos]; ok {
+			matrix[v.Goos] = append(val, v.Goarch)
+		} else {
+			matrix[v.Goos] = []string{v.Goarch}
+		}
+	}
+
+	return matrix, nil
+}
+
+func CrossBuild() error {
+	matrix, err := getBuildMatrix()
+	if err != nil {
+		return err
+	}
+
+	for os, arches := range matrix {
+		for _, arch := range arches {
+			env := map[string]string{
+				"GOOS":   os,
+				"GOARCH": arch,
+			}
+			if mg.Verbose() {
+				fmt.Printf("Building for GOOS=%s GOARCH=%s\n", os, arch)
+			}
+			if err := sh.RunWith(env, "go", "build", "./..."); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}