Initial waybar plugin framework for go

Signed-off-by: Jim Ramsay <i.am@jimramsay.com>

README.md

@@ -1,2 +1,44 @@
 # gowaybarplug
-Go framework for 
+
+Go framework for custom [Waybar](https://github.com/Alexays/Waybar) plugins
+
+# Usage
+
+First build a plugin that reports some interesting status:
+
+```go
+package main
+
+import (
+    "time"
+
+    waybar "github.com/lack/gowaybarplug"
+)
+
+main() {
+    updater := waybar.NewUpdater()
+    for {
+        status := waybar.Status{
+            Text: "Some text",
+            Toolbar: "Other text",
+        }
+        // Obviously do something more interesting than just static text in the status...
+        updater.Status <- &status
+        time.Sleep(15 * time.Second)
+    }
+}
+```
+
+Then add it to your ~/.config/waybar/config:
+
+```json
+{
+    // ... Other waybar config
+    "custom/mything": {
+        "format": "{} {icon}",
+        "return-type": "json",
+        "exec": "/path/to/my/new/plugin"
+        // etc
+    }
+}
+```

go.mod

@@ -0,0 +1,12 @@
+module github.com/lack/gowaybarplug
+
+go 1.18
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/objx v0.4.0 // indirect
+	github.com/stretchr/testify v1.8.0 // indirect
+	github.com/xorcare/pointer v1.1.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,17 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+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/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/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0 h1:M2gUjqZET1qApGOWNSnZ49BAIMX4F/1plDv3+l31EJ4=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/xorcare/pointer v1.1.0 h1:sFwXOhRF8QZ0tyVZrtxWGIoVZNEmRzBCaFWdONPQIUM=
+github.com/xorcare/pointer v1.1.0/go.mod h1:6KLhkOh6YbuvZkT4YbxIbR/wzLBjyMxOiNzZhJTor2Y=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

status.go

@@ -0,0 +1,31 @@
+package gowaybarplug
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// Status represents the json structure expected from waybar custom plugins.
+// See waybar-custom(5) for more details.
+type Status struct {
+	// Text is usually the label, represented by {} in a waybar format
+	Text string `json:"text"`
+	// Tooltip appears when you mouse-hover over the custom entry
+	Tooltip string `json:"tooltip,omitempty"`
+	// Class is a list of css classes that will be added to the waybat entry
+	Class []string `json:"class,omitempty"`
+	// Percentage can be added to format strings via the {percent} format string, but can also affect which icon is set in {icon} if the config specifies format-icons as an array.
+	Percentage *int `json:"percentage,omitempty"`
+	// Alt os the key used to look up the {icon} of format-icons is specified as a map.
+	Alt string `json:"alt,omitempty"`
+}
+
+// String renders the Status as a json string
+func (s *Status) String() string {
+	b, err := json.Marshal(s)
+	if err != nil {
+		// Fake json error reporting
+		return fmt.Sprintf(`"text": "Marshal error", "tooltip": "Marshal error: %s"}`, err.Error())
+	}
+	return string(b)
+}

status_test.go

@@ -0,0 +1,30 @@
+package gowaybarplug
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/xorcare/pointer"
+)
+
+func TestString(t *testing.T) {
+	tests := []struct {
+		input  Status
+		output string
+	}{{
+		input:  Status{},
+		output: `{"text":""}`,
+	}, {
+		input: Status{
+			Text:       "a",
+			Tooltip:    "b",
+			Class:      []string{"c1", "c2"},
+			Percentage: pointer.Int(42),
+			Alt:        "d",
+		},
+		output: `{"text":"a","tooltip":"b","class":["c1","c2"],"percentage":42,"alt":"d"}`,
+	}}
+	for _, test := range tests {
+		assert.Equal(t, test.input.String(), test.output)
+	}
+}

updater.go

@@ -0,0 +1,41 @@
+package gowaybarplug
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+// Updater runs a goroutine that accepts Status updates in a channel and ptints them to stdout.
+type Updater struct {
+	// Status is the main Status reporting channel. Every Status submitted here will be sent to stdout.
+	Status chan *Status
+
+	last   string
+	writer io.Writer
+}
+
+// Create a new Updater and start the receiver thread
+func NewUpdater() *Updater {
+	u := Updater{
+		Status: make(chan *Status, 10),
+		writer: os.Stdout,
+	}
+	go u.run()
+	return &u
+}
+
+func (u *Updater) run() {
+	for s := range u.Status {
+		next := s.String()
+		if next != u.last {
+			u.last = next
+			fmt.Fprintln(u.writer, next)
+		}
+	}
+}
+
+func (u *Updater) OutputTo(writer io.Writer) *Updater {
+	u.writer = writer
+	return u
+}

updater_test.go

@@ -0,0 +1,43 @@
+package gowaybarplug
+
+import (
+	"bytes"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type ChBuf struct {
+	Ch   chan bool
+	Buff bytes.Buffer
+}
+
+func NewChBuf() *ChBuf {
+	return &ChBuf{
+		Ch: make(chan bool, 100),
+	}
+}
+
+func (c *ChBuf) Write(data []byte) (int, error) {
+	n, err := c.Buff.Write(data)
+	c.Ch <- err == nil
+	return n, err
+}
+
+func (c *ChBuf) WaitForBuffer(deadline time.Duration) {
+	select {
+	case <-c.Ch:
+	case <-time.After(deadline):
+	}
+}
+
+func TestNewUpdater(t *testing.T) {
+	buff := NewChBuf()
+	u := NewUpdater().OutputTo(buff)
+	u.Ch <- &Status{Text: "test"}
+	buff.WaitForBuffer(2 * time.Second)
+	result, err := buff.Buff.ReadString('\n')
+	assert.NoError(t, err)
+	assert.Equal(t, result, "{\"text\":\"test\"}\n")
+}