feat: fetch service def from git

cli/build.go

@@ -18,7 +18,7 @@ func getBuildCommand() *cobra.Command {
 			if err != nil {
 				return fmt.Errorf("%+v", err)
 			}
-			def, err := service_definition.GetServiceDefinitionFromFile(pathProvided)
+			def, err := service_definition.GetServiceDefinition(pathProvided)
 
 			if err != nil {
 				return fmt.Errorf("Failed to read service definition from file: %+v", err)

service_definition/fetcher.go

@@ -3,9 +3,30 @@ package service_definition
 import (
 	"github.com/goccy/go-yaml"
 	"os"
+	"os/exec"
+	"strings"
 )
 
-func GetServiceDefinitionFromFile(path string) (ServiceDefinition, error) {
+// Clones the target git repository and uses it as a basis to extract
+// a service definition.
+func getDefinitionFromGit(path string) (ServiceDefinition, error) {
+	dir, err := os.MkdirTemp("/tmp", "spud-service-")
+
+	if err != nil {
+		return ServiceDefinition{}, err
+	}
+
+	cloneCmd := exec.Command("git", "clone", strings.TrimPrefix(path, "git+"), dir)
+
+	if err := cloneCmd.Run(); err != nil {
+		return ServiceDefinition{}, err
+	}
+
+	return getDefinitionFromFile(dir + "/service.yml")
+}
+
+// Extracts a service definition from the given filepath.
+func getDefinitionFromFile(path string) (ServiceDefinition, error) {
 	var definition ServiceDefinition
 
 	defData, err := os.ReadFile(path)

service_definition/main.go

@@ -1,5 +1,9 @@
 package service_definition
 
+import (
+	"strings"
+)
+
 type BuildImage struct {
 	Path      string `yaml:"path"`
 	TagPrefix string `yaml:"tag"`
@@ -45,5 +49,9 @@ type ServiceDefinition struct {
 }
 
 func GetServiceDefinition(path string) (ServiceDefinition, error) {
-	return GetServiceDefinitionFromFile(path)
+	if strings.HasPrefix(path, "git+") {
+		return getDefinitionFromGit(path)
+	}
+
+	return getDefinitionFromFile(path)
 }

service_definition/service_definition_test.go

@@ -5,7 +5,7 @@ import (
 )
 
 func TestGetServiceDefinitionFromFileDoesNotExist(t *testing.T) {
-	_, err := GetServiceDefinitionFromFile(t.TempDir() + "/not-a-file.yml")
+	_, err := GetServiceDefinition(t.TempDir() + "/not-a-file.yml")
 
 	if err == nil {
 		t.Errorf("Expected error, got nil.")