Allow setting global variables through the CLI

Closes #192

Author: andreynering

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## Unreleased
+
+- Allow setting global variables through the CLI
+  ([#192](https://github.com/go-task/task/issues/192)).
+
 ## 2.5.1 - 2019-04-27
 
 - Fixed some issues with interactive command line tools, where sometimes

cmd/task/task.go

@@ -121,9 +121,9 @@ func main() {
 		arguments = []string{"default"}
 	}
 
-	calls, err := args.Parse(arguments...)
-	if err != nil {
-		log.Fatal(err)
+	calls, globals := args.Parse(arguments...)
+	for name, value := range globals {
+		e.Taskfile.Vars[name] = value
 	}
 
 	ctx := context.Background()
@@ -132,7 +132,7 @@ func main() {
 	}
 
 	if status {
-		if err = e.Status(ctx, calls...); err != nil {
+		if err := e.Status(ctx, calls...); err != nil {
 			log.Fatal(err)
 		}
 		return

docs/usage.md

@@ -371,6 +371,12 @@ right before.
 $ task write-file FILE=file.txt "CONTENT=Hello, World!" print "MESSAGE=All done!"
 ```
 
+If you want to set global variables using this syntax, give it before any task:
+
+```bash
+$ task OUTPUT=file.txt generate-file
+```
+
 Example of locally declared vars:
 
 ```yaml
@@ -582,7 +588,7 @@ dependencies:
 commands:
  - your-release-tool
 ```
-If a summary is missing, the description will be printed. 
+If a summary is missing, the description will be printed.
 If the task does not have a summary or a description, a warning is printed.
 
 Please note: *showing the summary will not execute the command*.

internal/args/args.go

@@ -1,36 +1,43 @@
 package args
 
 import (
-	"errors"
 	"strings"
 
 	"github.com/go-task/task/v2/internal/taskfile"
 )
 
-var (
-	// ErrVariableWithoutTask is returned when variables are given before any task
-	ErrVariableWithoutTask = errors.New("task: variable given before any task")
-)
-
 // Parse parses command line argument: tasks and vars of each task
-func Parse(args ...string) ([]taskfile.Call, error) {
+func Parse(args ...string) ([]taskfile.Call, taskfile.Vars) {
 	var calls []taskfile.Call
+	var globals taskfile.Vars
 
 	for _, arg := range args {
 		if !strings.Contains(arg, "=") {
 			calls = append(calls, taskfile.Call{Task: arg})
 			continue
 		}
+
 		if len(calls) < 1 {
-			return nil, ErrVariableWithoutTask
-		}
+			if globals == nil {
+				globals = taskfile.Vars{}
+			}
 
-		if calls[len(calls)-1].Vars == nil {
-			calls[len(calls)-1].Vars = make(taskfile.Vars)
-		}
+			name, value := splitVar(arg)
+			globals[name] = taskfile.Var{Static: value}
+		} else {
+			if calls[len(calls)-1].Vars == nil {
+				calls[len(calls)-1].Vars = make(taskfile.Vars)
+			}
 
-		pair := strings.SplitN(arg, "=", 2)
-		calls[len(calls)-1].Vars[pair[0]] = taskfile.Var{Static: pair[1]}
+			name, value := splitVar((arg))
+			calls[len(calls)-1].Vars[name] = taskfile.Var{Static: value}
+		}
 	}
-	return calls, nil
+
+	return calls, globals
+}
+
+func splitVar(s string) (string, string) {
+	pair := strings.SplitN(s, "=", 2)
+	return pair[0], pair[1]
 }

internal/args/args_test.go

@@ -12,21 +12,21 @@ import (
 
 func TestArgs(t *testing.T) {
 	tests := []struct {
-		Args     []string
-		Expected []taskfile.Call
-		Err      error
+		Args            []string
+		ExpectedCalls   []taskfile.Call
+		ExpectedGlobals taskfile.Vars
 	}{
 		{
 			Args: []string{"task-a", "task-b", "task-c"},
-			Expected: []taskfile.Call{
+			ExpectedCalls: []taskfile.Call{
 				{Task: "task-a"},
 				{Task: "task-b"},
 				{Task: "task-c"},
 			},
 		},
 		{
 			Args: []string{"task-a", "FOO=bar", "task-b", "task-c", "BAR=baz", "BAZ=foo"},
-			Expected: []taskfile.Call{
+			ExpectedCalls: []taskfile.Call{
 				{
 					Task: "task-a",
 					Vars: taskfile.Vars{
@@ -45,7 +45,7 @@ func TestArgs(t *testing.T) {
 		},
 		{
 			Args: []string{"task-a", "CONTENT=with some spaces"},
-			Expected: []taskfile.Call{
+			ExpectedCalls: []taskfile.Call{
 				{
 					Task: "task-a",
 					Vars: taskfile.Vars{
@@ -55,16 +55,22 @@ func TestArgs(t *testing.T) {
 			},
 		},
 		{
-			Args: []string{"FOO=bar", "task-a"},
-			Err:  args.ErrVariableWithoutTask,
+			Args: []string{"FOO=bar", "task-a", "task-b"},
+			ExpectedCalls: []taskfile.Call{
+				{Task: "task-a"},
+				{Task: "task-b"},
+			},
+			ExpectedGlobals: taskfile.Vars{
+				"FOO": {Static: "bar"},
+			},
 		},
 	}
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("TestArgs%d", i+1), func(t *testing.T) {
-			calls, err := args.Parse(test.Args...)
-			assert.Equal(t, test.Err, err)
-			assert.Equal(t, test.Expected, calls)
+			calls, globals := args.Parse(test.Args...)
+			assert.Equal(t, test.ExpectedCalls, calls)
+			assert.Equal(t, test.ExpectedGlobals, globals)
 		})
 	}
 }