feat: add docker segment

resolves #3549

src/engine/segment.go

@@ -128,6 +128,8 @@ const (
 	DART SegmentType = "dart"
 	// DENO writes the active deno version
 	DENO SegmentType = "deno"
+	// DOCKER writes the docker context
+	DOCKER SegmentType = "docker"
 	// DOTNET writes which dotnet version is currently active
 	DOTNET SegmentType = "dotnet"
 	// ELIXIR writes the elixir version
@@ -259,6 +261,7 @@ var Segments = map[SegmentType]func() SegmentWriter{
 	CMAKE:         func() SegmentWriter { return &segments.Cmake{} },
 	DART:          func() SegmentWriter { return &segments.Dart{} },
 	DENO:          func() SegmentWriter { return &segments.Deno{} },
+	DOCKER:        func() SegmentWriter { return &segments.Docker{} },
 	DOTNET:        func() SegmentWriter { return &segments.Dotnet{} },
 	EXECUTIONTIME: func() SegmentWriter { return &segments.Executiontime{} },
 	ELIXIR:        func() SegmentWriter { return &segments.Elixir{} },

src/segments/docker.go

@@ -0,0 +1,72 @@
+package segments
+
+import (
+	"encoding/json"
+	"path/filepath"
+
+	"github.com/jandedobbeleer/oh-my-posh/src/platform"
+	"github.com/jandedobbeleer/oh-my-posh/src/properties"
+)
+
+type DockerConfig struct {
+	CurrentContext string `json:"currentContext"`
+}
+
+type Docker struct {
+	props properties.Properties
+	env   platform.Environment
+
+	Context string
+}
+
+func (d *Docker) Template() string {
+	return " \uf308 {{ .Context }} "
+}
+
+func (d *Docker) Init(props properties.Properties, env platform.Environment) {
+	d.props = props
+	d.env = env
+}
+
+func (d *Docker) envVars() []string {
+	return []string{"DOCKER_MACHINE_NAME", "DOCKER_HOST", "DOCKER_CONTEXT"}
+}
+
+func (d *Docker) configFiles() []string {
+	return []string{
+		filepath.Join(d.env.Home(), "/.docker/config.json"),
+		filepath.Join(d.env.Getenv("DOCKER_CONFIG"), "/config.json"),
+	}
+}
+
+func (d *Docker) Enabled() bool {
+	// Check if there is a non-empty environment variable named `DOCKER_HOST` or `DOCKER_CONTEXT`
+	// These variables are set by the docker CLI and override the config file
+	// Return the current context if it is not empty and not `default`
+	for _, v := range d.envVars() {
+		context := d.env.Getenv(v)
+		if len(context) > 0 && context != "default" {
+			d.Context = context
+			return true
+		}
+	}
+
+	// Check if there is a file named `$HOME/.docker/config.json` or `$DOCKER_CONFIG/config.json`
+	// Return the current context if it is not empty and not `default`
+	for _, f := range d.configFiles() {
+		if !d.env.HasFiles(f) {
+			continue
+		}
+		data := d.env.FileContent(f)
+		var cfg DockerConfig
+		if err := json.Unmarshal([]byte(data), &cfg); err != nil {
+			continue
+		}
+		if len(cfg.CurrentContext) > 0 && cfg.CurrentContext != "default" {
+			d.Context = cfg.CurrentContext
+			return true
+		}
+	}
+
+	return false
+}

src/segments/docker_test.go

@@ -0,0 +1,60 @@
+package segments
+
+import (
+	"testing"
+
+	"github.com/jandedobbeleer/oh-my-posh/src/mock"
+	"github.com/jandedobbeleer/oh-my-posh/src/properties"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDockerSegment(t *testing.T) {
+	type envVar struct {
+		name  string
+		value string
+	}
+	cases := []struct {
+		Case            string
+		Expected        string
+		ExpectedEnabled bool
+		EnvVar          envVar
+		HasFiles        bool
+		ConfigFile      string
+	}{
+		{Case: "DOCKER_MACHINE_NAME", Expected: "alpine", ExpectedEnabled: true, EnvVar: envVar{name: "DOCKER_MACHINE_NAME", value: "alpine"}},
+		{Case: "DOCKER_HOST", Expected: "alpine 2", ExpectedEnabled: true, EnvVar: envVar{name: "DOCKER_HOST", value: "alpine 2"}},
+		{Case: "DOCKER_CONTEXT", Expected: "alpine 3", ExpectedEnabled: true, EnvVar: envVar{name: "DOCKER_HOST", value: "alpine 3"}},
+		{Case: "DOCKER_CONTEXT - default", ExpectedEnabled: false, EnvVar: envVar{name: "DOCKER_HOST", value: "default"}},
+		{Case: "no docker context active", ExpectedEnabled: false},
+		{Case: "config file", Expected: "alpine", ExpectedEnabled: true, HasFiles: true, ConfigFile: `{"currentContext": "alpine"}`},
+		{Case: "config file - default", ExpectedEnabled: false, HasFiles: true, ConfigFile: `{"currentContext": "default"}`},
+		{Case: "config file - broken", ExpectedEnabled: false, HasFiles: true, ConfigFile: `{`},
+	}
+
+	for _, tc := range cases {
+		docker := &Docker{}
+		env := new(mock.MockedEnvironment)
+		docker.Init(properties.Map{}, env)
+
+		for _, v := range docker.envVars() {
+			var value string
+			if v == tc.EnvVar.name {
+				value = tc.EnvVar.value
+			}
+			env.On("Getenv", v).Return(value)
+		}
+
+		env.On("Home").Return("")
+		env.On("Getenv", "DOCKER_CONFIG").Return("")
+		for _, f := range docker.configFiles() {
+			env.On("HasFiles", f).Return(tc.HasFiles)
+			env.On("FileContent", f).Return(tc.ConfigFile)
+		}
+
+		assert.Equal(t, tc.ExpectedEnabled, docker.Enabled(), tc.Case)
+		if tc.ExpectedEnabled {
+			assert.Equal(t, tc.Expected, renderTemplate(env, "{{ .Context }}", docker), tc.Case)
+		}
+	}
+}

themes/schema.json

@@ -255,6 +255,7 @@
             "cf",
             "cftarget",
             "cmake",
+            "docker",
             "dotnet",
             "dart",
             "exit",
@@ -717,6 +718,19 @@
             }
           }
         },
+        {
+          "if": {
+            "properties": {
+              "type": {
+                "const": "docker"
+              }
+            }
+          },
+          "then": {
+            "title": "Docker Segment",
+            "description": "https://ohmyposh.dev/docs/segments/docker"
+          }
+        },
         {
           "if": {
             "properties": {

website/docs/segments/docker.mdx

@@ -0,0 +1,41 @@
+---
+id: docker
+title: Docker
+sidebar_label: Docker
+---
+
+## What
+
+Display the current Docker context. Will not be active when using the default context.
+
+## Sample Configuration
+
+```json
+{
+  "type": "docker",
+  "style": "powerline",
+  "powerline_symbol": "\uE0B0",
+  "foreground": "#000000",
+  "background": "#0B59E7",
+  "template": " \uf308 {{ .Context }} "
+}
+```
+
+## Template ([info][templates])
+
+:::note default template
+
+```template
+\uf308 {{ .Context }}
+```
+
+:::
+
+### Properties
+
+| Name       | Type     | Description                |
+| ---------- | -------- | -------------------------- |
+| `.Context` | `string` | the current active context |
+
+[go-text-template]: https://golang.org/pkg/text/template/
+[templates]: /docs/configuration/templates

website/sidebars.js

@@ -67,6 +67,7 @@ module.exports = {
         "segments/crystal",
         "segments/dart",
         "segments/deno",
+        "segments/docker",
         "segments/dotnet",
         "segments/elixir",
         "segments/executiontime",