fixed waitgroup

.vscode/launch.json

@@ -2,37 +2,23 @@
   "version": "0.0.1",
   "configurations": [
     {
-      "name": "slideshow-scaled",
+      "name": "slideshow",
       "type": "go",
       "request": "launch",
       "mode": "auto",
       "program": "${workspaceFolder}/main.go",
       "env":{
-        "SLIDESHOW_INTERVAL": "10",
+        "SLIDESHOW_API": "localhost:3000",
-        "SLIDESHOW_DIRECTORY": "/home/velvettear/images",
+        "SLIDESHOW_INTERVAL": "3",
-        "SLIDESHOW_SCANINTERVAL": "300",
+        "SLIDESHOW_RESOLUTION": "",
-        "SLIDESHOW_RESOLUTION": "600x1024",
+        "SLIDESHOW_PALETTE": "",
+        "SLIDESHOW_PALETTE_ALGORITHM": "",
+        "SLIDESHOW_PALETTE_COLORS": "",
+        "SLIDESHOW_SCRIPT": "",
+        "SLIDESHOW_SCRIPT_ARGS": "",
+        "SLIDESHOW_SCRIPT_ASYNC": "",
+        "SLIDESHOW_SCRIPT_STAGE": "",
         "SLIDESHOW_LOGLEVEL": "debug",
-        "SLIDESHOW_PALETTE": "/tmp/.slideshow.palette",
-        "SLIDESHOW_PALETTE_ALGORITHM": "wsm",
-        "SLIDESHOW_PALETTE_COLORS": "32"
-      },
-      "console": "integratedTerminal"
-    },
-    {
-      "name": "slideshow-unscaled",
-      "type": "go",
-      "request": "launch",
-      "mode": "auto",
-      "program": "${workspaceFolder}/main.go",
-      "env":{
-        "SLIDESHOW_INTERVAL": "10",
-        "SLIDESHOW_DIRECTORY": "/home/velvettear/images",
-        "SLIDESHOW_SCANINTERVAL": "10",
-        "SLIDESHOW_LOGLEVEL": "debug",
-        "SLIDESHOW_PALETTE": "/tmp/.slideshow.palette",
-        "SLIDESHOW_PALETTE_ALGORITHM": "wsm",
-        "SLIDESHOW_PALETTE_COLORS": "16"
       },
       "console": "integratedTerminal"
     }

README.md

@@ -1,11 +1,11 @@
 # slideshow
 
-a simple cli application to start a background image slideshow using 'feh'.
+client for the [slideshow-api](https://git.velvettear.de/velvettear/slideshow-api).  
+sets (scaled) images as background via 'feh', retrieves color palettes (and executes a script).
 
 ## requirements
 
 - [feh](https://feh.finalrewind.org/)
-- [ImageMagick](https://imagemagick.org/) (optional)
 
 ## configuration
 
@@ -13,19 +13,32 @@ configuration is entirely done via environment variables.
 
 | variable                    | default           | description                                                |
 | --------------------------- | ----------------- | -----------------------------------------------------------|
+| SLIDESHOW_API               |                   | the address of the slideshow-api server                    |
 | SLIDESHOW_INTERVAL          | 60                | the interval of the slideshow in seconds                   |
-| SLIDESHOW_DIRECTORY         | "$HOME"           | path to a directory containing images                      |
-| SLIDESHOW_SCANINTERVAL      | 60                | the interval for directory scans in seconds 
 | SLIDESHOW_RESOLUTION        |                   | the resolution to which images are scaled (i.e. 1920x1080) | 
 | SLIDESHOW_PALETTE           |                   | path to a file where the color palette will be stored      |
 | SLIDESHOW_PALETTE_ALGORITHM | "wsm"             | the algorithm used to generate the color palette           |
 | SLIDESHOW_PALETTE_COLORS    | 16                | the amount of colors generated                             |
+| SLIDESHOW_SCRIPT            |                   | path to a script to execute each loop                      |
+| SLIDESHOW_SCRIPT_ARGS       |                   | arguments to pass to the script                            |
+| SLIDESHOW_SCRIPT_ASYNC      | false             | run the script asynchronously (in a goroutine)             |
+| SLIDESHOW_SCRIPT_STAGE      |                   | the stage at which the script is executed                  |
 | SLIDESHOW_LOGLEVEL          | "info"            | the log level                                              |
 
 **note:**  
-if no resolution is set the images will be displayed as they are (without any scaling).
 
-**available log levels:**
+- if `SLIDESHOW_RESOLUTION` is unset images will be requested in their original resolution.
+- if `SLIDESHOW_PALETTE` is unset no color palettes will be requested.  
+- if `SLIDESHOW_SCRIPT_STAGE` is unset the script (if specified) will be executed **after** the background image has been set **and** the color palette file has been generated.
+
+### stages:
+
+- `pre_image`: executes the script **before** the background image will be set.
+- `post_image`: executes the script **after** the background image has been set.
+- `pre_palette`: executes the script **before** the color palette file will be generated.
+- `post_palette`: executes the script **after** the color palette has been generated.
+
+### log levels:
 
 - `debug`
 - `info`

go.mod

@@ -6,8 +6,7 @@ require git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084
 
 require (
 	github.com/fatih/color v1.16.0 // indirect
-	github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	golang.org/x/sys v0.14.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
 )

go.sum

@@ -2,8 +2,6 @@ git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084 h1:13S20q+
 git.velvettear.de/velvettear/loggo v0.0.0-20231113084149-980a00b4e084/go.mod h1:Jjjno0vz7v1Y6tCnpQHnq2TVL2+5m7TXkmNNYYREIMo=
 github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
 github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
-github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808 h1:9JJaKNm4eDnB/ad7rWfejfMw+1ufpchM8Eik9VcQzUQ=
-github.com/kennykarnama/color-thief v0.0.0-20230222041546-c1bf65ec0808/go.mod h1:9qLIEhoYLAXPjhQQpgR0nVnhJxNXBtAqRZAp2Dj87WQ=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
@@ -13,3 +11,5 @@ golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
 golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
+golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

images/cache.go

@@ -1,105 +0,0 @@
-package images
-
-// import (
-// 	"runtime"
-// 	"strconv"
-// 	"sync"
-// 	"time"
-
-// 	"git.velvettear.de/velvettear/image-frame/config"
-// 	"git.velvettear.de/velvettear/loggo"
-// )
-
-// // cache for scaled images
-// var cache []scaledImage
-
-// // timestamp of the next cache rotation
-// var NextRotation time.Time
-
-// // get the previous image from the history and set it as the first scaled image in the cache
-// func SetPreviousImage() error {
-// 	previousImage, error := getLatestFromHistory()
-// 	if error != nil {
-// 		return error
-// 	}
-// 	var tmpCache []scaledImage
-// 	tmpCache = append(tmpCache, previousImage)
-// 	tmpCache = append(tmpCache, cache...)
-// 	cache = tmpCache
-// 	tmpCache = nil
-// 	return nil
-// }
-
-// // get the first scaled image from the cache
-// func GetCachedImage() scaledImage {
-// 	return cache[0]
-// }
-
-// // replace the first element in the cache with the last one and add a new scaled image to the cache
-// func RotateCache() {
-// 	addToHistory(GetCachedImage())
-// 	loggo.Debug("removing first element from image cache...")
-// 	cacheSize := len(cache)
-// 	if cacheSize == 1 {
-// 		cache = nil
-// 		cacheImages()
-// 		return
-// 	}
-// 	cacheSize--
-// 	cache[0] = cache[cacheSize]
-// 	cache = cache[:cacheSize]
-// 	go cacheImages()
-// }
-
-// // start the "slideshow" in a goroutine - rotate the cache based on the set interval
-// func startSlideshow() {
-// 	go func() {
-// 		interval := time.Duration(config.GetImageSlideshowInterval()) * time.Second
-// 		for {
-// 			NextRotation = time.Now().Add(interval)
-// 			time.Sleep(interval)
-// 			RotateCache()
-// 		}
-// 	}()
-// }
-
-// // fill the cache with scaled images
-// func cacheImages() {
-// 	timestamp := time.Now().UnixMilli()
-// 	imageCount := len(images)
-// 	cacheSize := len(cache)
-// 	cacheLimit := config.GetImageCache()
-// 	if imageCount < cacheLimit {
-// 		cacheLimit = imageCount
-// 	}
-// 	imagesToCache := cacheLimit - cacheSize
-// 	if imagesToCache <= 0 {
-// 		return
-// 	}
-// 	concurrency := runtime.NumCPU()
-// 	if imagesToCache < concurrency {
-// 		concurrency = imagesToCache
-// 	}
-// 	loggo.Debug("filling image cache with "+strconv.Itoa(imagesToCache)+" element(s)", "concurrency: "+strconv.Itoa(concurrency))
-// 	var waitgroup sync.WaitGroup
-// 	waitgroup.Add(imagesToCache)
-// 	channel := make(chan struct{}, concurrency)
-// 	var cached int
-// 	for cached = 0; cached < imagesToCache; cached++ {
-// 		channel <- struct{}{}
-// 		var randomScaledImage scaledImage
-// 		randomScaledImage.Name = getRandomImage()
-// 		if randomScaledImage.isCached() {
-// 			continue
-// 		}
-// 		go func(randomScaledImage scaledImage) {
-// 			randomScaledImage.Data = scale(randomScaledImage.Name, config.GetImageWidth(), config.GetImageHeight())
-// 			cache = append(cache, randomScaledImage)
-// 			loggo.Debug("added scaled image '" + randomScaledImage.Name + "' to cache")
-// 			<-channel
-// 			waitgroup.Done()
-// 		}(randomScaledImage)
-// 	}
-// 	waitgroup.Wait()
-// 	loggo.DebugTimed("filled image cache with "+strconv.Itoa(cached)+" images", timestamp)
-// }

images/history.go

@@ -1,40 +0,0 @@
-package images
-
-// import (
-// 	"errors"
-// 	"strconv"
-// 	"time"
-
-// 	"git.velvettear.de/velvettear/image-frame/config"
-// 	"git.velvettear.de/velvettear/loggo"
-// )
-
-// // internal history of displayed images
-// var history []scaledImage
-
-// // add a image to the history
-// func addToHistory(scaledImage scaledImage) {
-// 	timestamp := time.Now().UnixMilli()
-// 	historyLimit := config.GetImageSlideshowHistory()
-// 	if historyLimit <= 0 {
-// 		return
-// 	}
-// 	history = append(history, scaledImage)
-// 	diff := len(history) - historyLimit
-// 	if diff > 0 {
-// 		history = history[diff:]
-// 	}
-// 	loggo.DebugTimed("added image to history", timestamp, "history size: "+strconv.Itoa(len(history)))
-// }
-
-// // get and remove the latest image from history
-// func getLatestFromHistory() (scaledImage, error) {
-// 	var scaledImage scaledImage
-// 	if len(history) == 0 {
-// 		return scaledImage, errors.New("history is empty")
-// 	}
-// 	index := len(history) - 1
-// 	scaledImage = history[index]
-// 	history = history[:index]
-// 	return scaledImage, nil
-// }

images/initialize.go

@@ -1,7 +0,0 @@
-package images
-
-// func Initialize() {
-// 	scanForImages()
-// 	cacheImages()
-// 	startSlideshow()
-// }

images/scaledimage.go

@@ -1,31 +0,0 @@
-package images
-
-// import (
-// 	"math/rand"
-// )
-
-// // struct for scaled images
-// type scaledImage struct {
-// 	Name string
-// 	Data []byte
-// }
-
-// // get a random image
-// func getRandomImage() string {
-// 	return images[rand.Intn(len(images)-1)]
-// }
-
-// // check if the scaled image is already cached
-// func (scaledImage *scaledImage) isCached() bool {
-// 	return isCached(scaledImage.Name)
-// }
-
-// // check (by name) if the scaled image is already cached
-// func isCached(scaledImageName string) bool {
-// 	for _, cachedImage := range cache {
-// 		if cachedImage.Name == scaledImageName {
-// 			return true
-// 		}
-// 	}
-// 	return false
-// }

internal/config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"os"
+	"os/exec"
 	"strconv"
 	"strings"
 	"time"
@@ -9,49 +10,39 @@ import (
 	"git.velvettear.de/velvettear/loggo"
 )
 
+var ApiAddress string
 var Interval time.Duration
-var Directory string
-var ScanInterval time.Duration
 var Resolution string
 var PaletteFile string
-var PaletteAlgorithm int
+var PaletteAlgorithm string
 var PaletteColors int
+var Script string
+var ScriptArgs []string
+var ScriptAsync bool
+var ScriptStage string
 
 // initialize the config
 func Initialize() {
 	loggo.SetLogLevelByName(os.Getenv("SLIDESHOW_LOGLEVEL"))
+	ApiAddress = os.Getenv("SLIDESHOW_API")
+	if len(ApiAddress) == 0 {
+		loggo.Fatal("no adress of the slideshow-api server has been specified")
+	}
+	if !strings.HasPrefix(ApiAddress, "http://") && !strings.HasPrefix(ApiAddress, "https://") {
+		ApiAddress = "http://" + ApiAddress
+	}
 	tmpInt, _ := strconv.Atoi(os.Getenv("SLIDESHOW_INTERVAL"))
 	if tmpInt <= 0 {
 		tmpInt = 60
 	}
 	Interval = time.Duration(tmpInt) * time.Second
-	Directory = os.Getenv("SLIDESHOW_DIRECTORY")
-	if len(Directory) == 0 {
-		tmp, error := os.UserHomeDir()
-		if error != nil {
-			loggo.Fatal("encountered an error getting the current user's home directory", error.Error())
-		}
-		Directory = tmp
-	}
-	stats, error := os.Stat(Directory)
-	if error != nil {
-		loggo.Fatal("encountered an error checking the directory '"+Directory+"'", error.Error())
-	}
-	if !stats.IsDir() {
-		loggo.Fatal("configured directory '" + Directory + "' is not a valid directory")
-	}
-	tmpInt, _ = strconv.Atoi(os.Getenv("SLIDESHOW_SCANINTERVAL"))
-	if tmpInt <= 0 {
-		tmpInt = 60
-	}
-	ScanInterval = time.Duration(tmpInt) * time.Second
 	Resolution = os.Getenv("SLIDESHOW_RESOLUTION")
 	if len(Resolution) > 0 {
 		width, height, found := strings.Cut(Resolution, "x")
 		if !found {
 			loggo.Fatal("encountered an error parsing the configured resolution, make sure to specify the format like '1920x1080'")
 		}
-		_, error = strconv.Atoi(width)
+		_, error := strconv.Atoi(width)
 		if error != nil {
 			loggo.Fatal("encountered an error parsing the configured width '" + width + "'")
 		}
@@ -61,17 +52,67 @@ func Initialize() {
 		}
 	}
 	PaletteFile = os.Getenv("SLIDESHOW_PALETTE")
-	tmpString := os.Getenv("SLIDESHOW_PALETTE_ALGORITHM")
+	PaletteAlgorithm = os.Getenv("SLIDESHOW_PALETTE_ALGORITHM")
-	if strings.ToLower(tmpString) == "wu" {
-		PaletteAlgorithm = 0
-	} else {
-		PaletteAlgorithm = 1
-	}
 	tmpInt, _ = strconv.Atoi(os.Getenv("SLIDESHOW_PALETTE_COLORS"))
 	if tmpInt <= 0 {
 		tmpInt = 16
 	}
 	PaletteColors = tmpInt
+	Script = os.Getenv("SLIDESHOW_SCRIPT")
+	ScriptArgs = strings.Split(os.Getenv("SLIDESHOW_SCRIPT_ARGS"), " ")
+	ScriptAsync, _ = strconv.ParseBool(os.Getenv("SLIDESHOW_SCRIPT_ASYNC"))
+	ScriptStage = strings.ToLower(os.Getenv("SLIDESHOW_SCRIPT_STAGE"))
+	checkScript()
+	checkFehCommand()
+}
+
+// check if a script has been specified and exists
+func checkScript() {
+	if len(Script) == 0 {
+		return
+	}
+	stats, error := os.Stat(Script)
+	if error != nil {
+		loggo.Warning("encountered an error getting stats for the script '"+Script+"', script execution is unavailable", error.Error())
+		Script = ""
+		return
+	}
+	if stats.IsDir() {
+		loggo.Warning("the script '"+Script+"' seems to be a directory, script execution is unavailable", error.Error())
+		Script = ""
+		return
+	}
+	if string(stats.Mode().Perm().String()[3]) != "x" {
+		loggo.Warning("the script '"+Script+"' seems to be a directory, script execution is unavailable", error.Error())
+		Script = ""
+	}
+	checkScriptStage()
+}
+
+// check if the specified script stage is valid
+func checkScriptStage() {
+	switch ScriptStage {
+	case "pre_image":
+		fallthrough
+	case "post_image":
+		fallthrough
+	case "pre_palette":
+		fallthrough
+	case "post_palette":
+		return
+	default:
+		ScriptStage = ""
+	}
+}
+
+// check if 'feh' is available
+func checkFehCommand() {
+	cmd := exec.Command("which", "feh")
+	error := cmd.Run()
+	if error == nil {
+		return
+	}
+	loggo.Fatal("could not find command 'feh'")
 }
 
 // check if a resolution has been specified
@@ -83,3 +124,33 @@ func IsResolutionSet() bool {
 func IsPaletteSet() bool {
 	return len(PaletteFile) > 0
 }
+
+// check if a script has been specified
+func IsScriptSet() bool {
+	return len(Script) > 0
+}
+
+// check if a script stage has been specified
+func IsScriptStageSet() bool {
+	return len(ScriptStage) > 0
+}
+
+// check if script stage 'pre_image' has been specified
+func IsScriptStagePreImage() bool {
+	return ScriptStage == "pre_image"
+}
+
+// check if script stage 'post_image' has been specified
+func IsScriptStagePostImage() bool {
+	return ScriptStage == "post_image"
+}
+
+// check if script stage 'pre_palette' has been specified
+func IsScriptStagePrePalette() bool {
+	return ScriptStage == "pre_palette"
+}
+
+// check if script stage 'post_palette' has been specified
+func IsScriptStagePostPalette() bool {
+	return ScriptStage == "post_palette"
+}

internal/formatter.go

@@ -0,0 +1,17 @@
+package internal
+
+import "strconv"
+
+// format bytes
+func FormatBytes(bytes int64) string {
+	value := float64(bytes)
+	unit := "bytes"
+	if bytes > 1000000 {
+		value = value / 1000000
+		unit = "mega" + unit
+	} else if bytes > 1000 {
+		value = value / 1000
+		unit = "kilo" + unit
+	}
+	return strconv.FormatFloat(value, 'f', 2, 64) + " " + unit
+}

internal/requests.go

@@ -0,0 +1,101 @@
+package internal
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+)
+
+// get the endpoint url of the api
+func getEndpointUrl(endpoint string) string {
+	url := config.ApiAddress
+	if !strings.HasSuffix(url, "/") && endpoint != "/" {
+		url += "/"
+	}
+	if len(endpoint) > 0 {
+		url += endpoint
+	}
+	if !strings.HasSuffix(url, "/") {
+		url += "/"
+	}
+	return url
+}
+
+// request the name of an image from the api
+func requestImageName() (string, error) {
+	timestamp := time.Now().UnixMilli()
+	var name string
+	url := getEndpointUrl("/")
+	request, error := http.NewRequest("GET", url, nil)
+	if error != nil {
+		return name, error
+	}
+	client := http.Client{}
+	response, error := client.Do(request)
+	if error != nil {
+		return name, error
+	}
+	bytes, error := io.ReadAll(response.Body)
+	if error != nil {
+		return name, error
+	}
+	tmp := make(map[string]interface{})
+	error = json.Unmarshal(bytes, &tmp)
+	if error != nil {
+		return name, error
+	}
+	name = tmp["Content"].(string)
+	loggo.DebugTimed("successfully requested image '"+name+"'", timestamp, "url: "+url)
+	return name, nil
+}
+
+// request the data stream of an image by name from the api
+func requestImageData(name string) (io.ReadCloser, error) {
+	timestamp := time.Now().UnixMilli()
+	var stream io.ReadCloser
+	url := getEndpointUrl("/image/") + name
+	request, error := http.NewRequest("GET", url, nil)
+	if error != nil {
+		return stream, error
+	}
+	queryParameters := request.URL.Query()
+	if config.IsResolutionSet() {
+		queryParameters.Set("resolution", config.Resolution)
+	}
+	request.URL.RawQuery = queryParameters.Encode()
+	client := http.Client{}
+	response, error := client.Do(request)
+	if error != nil {
+		return stream, error
+	}
+	loggo.DebugTimed("successfully requested data stream for image '"+name+"'", timestamp)
+	return response.Body, nil
+}
+
+// request the color palette of an image by name from the api as stream
+func requestColorPalette(name string) (io.ReadCloser, error) {
+	timestamp := time.Now().UnixMilli()
+	var stream io.ReadCloser
+	url := getEndpointUrl("/palette/") + name
+	request, error := http.NewRequest("GET", url, nil)
+	if error != nil {
+		return stream, error
+	}
+	queryParameters := request.URL.Query()
+	queryParameters.Set("colors", strconv.Itoa(config.PaletteColors))
+	queryParameters.Set("algorithm", config.PaletteAlgorithm)
+	request.URL.RawQuery = queryParameters.Encode()
+	client := http.Client{}
+	response, error := client.Do(request)
+	if error != nil {
+		return stream, error
+	}
+	loggo.DebugTimed("successfully requested color palette stream for image '"+name+"'", timestamp)
+	return response.Body, nil
+}

internal/slideshow.go

@@ -0,0 +1,115 @@
+package internal
+
+import (
+	"os/exec"
+	"strconv"
+	"sync"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal/config"
+)
+
+var loop int64
+
+// start the loop for the slideshow
+func StartSlideshow() {
+	for {
+		timestamp := time.Now().UnixMilli()
+		loop++
+		imageLoop()
+		loggo.InfoTimed("slideshow loop #"+strconv.FormatInt(loop, 10)+" finished", timestamp)
+		loggo.Debug("sleeping for " + strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64) + " seconds...")
+		time.Sleep(config.Interval)
+	}
+}
+
+// the image loop of the slideshoow
+func imageLoop() {
+	name, error := requestImageName()
+	if error != nil {
+		loggo.Error("encountered an error requesting the name of an image", error.Error())
+		return
+	}
+	var waitgroup sync.WaitGroup
+	waitgroup.Add(2)
+	go setBackground(name, &waitgroup)
+	go exportColorPalette(name, &waitgroup)
+	waitgroup.Wait()
+	if !config.IsScriptStageSet() {
+		runScript(false)
+	}
+}
+
+// encapsulated method to set the background image in a goroutine
+func setBackground(name string, waitgroup *sync.WaitGroup) {
+	timestamp := time.Now().UnixMilli()
+	defer waitgroup.Done()
+	if config.IsScriptStagePreImage() {
+		runScript(false)
+	}
+	stream, error := requestImageData(name)
+	if error != nil {
+		loggo.Error("encountered an error requesting the data stream for image '"+name+"'", error.Error())
+		return
+	}
+	error = streamToFeh(stream)
+	if error != nil {
+		loggo.Error("encountered an error piping the data stream for image '"+name+"' to 'feh'", error.Error())
+	}
+	loggo.InfoTimed("set new background image '"+name+"' via 'feh'", timestamp)
+	if config.IsScriptStagePostImage() {
+		runScript(false)
+	}
+}
+
+// encapsulated method to set the background image in a goroutine
+func exportColorPalette(name string, waitgroup *sync.WaitGroup) {
+	timestamp := time.Now().UnixMilli()
+	defer waitgroup.Done()
+	if !config.IsPaletteSet() {
+		return
+	}
+	if config.IsScriptStagePrePalette() {
+		runScript(false)
+	}
+	stream, error := requestColorPalette(name)
+	if error != nil {
+		loggo.Error("encountered an error requesting the data stream for the color palette of image '"+name+"'", error.Error())
+		return
+	}
+	error = streamToFile(stream, config.PaletteFile)
+	if error != nil {
+		loggo.Error("encountered an error piping the data stream for the color palette of image '"+name+"' to file '"+config.PaletteFile+"'", error.Error())
+	}
+	loggo.InfoTimed("exported color palette of image '"+name+"' to  '"+config.PaletteFile+"'", timestamp)
+	if config.IsScriptStagePostPalette() {
+		runScript(false)
+	}
+}
+
+// encapsulated method to run the defined script
+func runScript(running bool) {
+	if !running && config.ScriptAsync {
+		go runScript(true)
+		return
+	}
+	timestamp := time.Now().UnixMilli()
+	if !config.IsScriptSet() {
+		return
+	}
+	cmd := exec.Command(config.Script, config.ScriptArgs...)
+	error := cmd.Run()
+	if error != nil {
+		loggo.Error("encountered an error executing the script '"+config.Script+"'", error.Error())
+		return
+	}
+	var extras []string
+	if config.ScriptAsync {
+		extras = append(extras, "async: "+strconv.FormatBool(config.ScriptAsync))
+	}
+	if config.IsScriptStageSet() {
+		extras = append(extras, "stage: "+config.ScriptStage)
+	}
+	loggo.InfoTimed("executed script '"+config.Script+"'", timestamp, extras...)
+}

internal/slideshow/palette.go

@@ -1,86 +0,0 @@
-package slideshow
-
-import (
-	"bytes"
-	"fmt"
-	"image"
-	"image/color"
-	"os"
-	"strconv"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-	color_thief "github.com/kennykarnama/color-thief"
-)
-
-// write the base16 color palette to a file
-func exportPalette(colors []color.Color) {
-	if len(colors) == 0 || !config.IsPaletteSet() {
-		return
-	}
-	timestamp := time.Now().UnixMilli()
-	var palette string
-	for index, color := range colors {
-		if index > 0 {
-			palette += "\n"
-		}
-		tmp := strconv.Itoa(index)
-		if len(tmp) < 2 {
-			tmp = "0" + tmp
-		}
-		tmp = "SLIDESHOW_COLOR" + tmp
-		palette += tmp + "=\"" + rgbToHex(color) + "\""
-	}
-	error := os.WriteFile(config.PaletteFile, []byte(palette), 0775)
-	if error != nil {
-		loggo.ErrorTimed("encountered an error exporting a color palette", timestamp, error.Error())
-	} else {
-		loggo.DebugTimed("exported color palette to filesystem", timestamp, "path: "+config.PaletteFile)
-	}
-}
-
-// extract the given amount of dominant colors of raw image bytes
-func getColorPaletteRaw(data []byte) ([]color.Color, error) {
-	var colors []color.Color
-	if !config.IsPaletteSet() {
-		return colors, nil
-	}
-	timestamp := time.Now().UnixMilli()
-	amount := config.PaletteColors
-	img, _, error := image.Decode(bytes.NewReader(data))
-	if error != nil {
-		loggo.ErrorTimed("encountered an error decoding the provided raw image bytes to an image", timestamp, error.Error())
-		return colors, error
-	}
-	colors, error = color_thief.GetPalette(img, amount, config.PaletteAlgorithm)
-	if error != nil {
-		loggo.ErrorTimed("encountered an error generating the color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
-	} else {
-		loggo.DebugTimed("generated color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
-	}
-	return colors, error
-}
-
-// extract the given amount of dominant colors of an image
-func getColorPalette(image string) ([]color.Color, error) {
-	var colors []color.Color
-	if !config.IsPaletteSet() {
-		return colors, nil
-	}
-	timestamp := time.Now().UnixMilli()
-	amount := config.PaletteColors
-	colors, error := color_thief.GetPaletteFromFile(image, amount, config.PaletteAlgorithm)
-	if error != nil {
-		loggo.ErrorTimed("encountered an error generating the color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
-	} else {
-		loggo.DebugTimed("generated color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
-	}
-	return colors, error
-}
-
-// parse rgb color values to hex
-func rgbToHex(color color.Color) string {
-	r, g, b, _ := color.RGBA()
-	return fmt.Sprintf("#%02x%02x%02x", uint8(r>>8), uint8(g>>8), uint8(b>>8))
-}

internal/slideshow/scale.go

@@ -1,44 +0,0 @@
-package slideshow
-
-import (
-	"errors"
-	"io"
-	"os/exec"
-	"strconv"
-	"strings"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-)
-
-// scale an image
-func scale(image string) ([]byte, error) {
-	timestamp := time.Now().UnixMilli()
-	cmd := exec.Command("convert", image, "-resize", config.Resolution+"^", "-gravity", "center", "-extent", config.Resolution, "-")
-	stdout, stdoutError := cmd.StdoutPipe()
-	stderr, stderrError := cmd.StderrPipe()
-	var data []byte
-	cmd.Start()
-	if stdoutError != nil {
-		return data, stdoutError
-	}
-	if stderrError != nil {
-		return data, stdoutError
-	}
-	data, stdoutError = io.ReadAll(stdout)
-	if stdoutError != nil {
-		return data, stdoutError
-	}
-	errorBytes, stderrError := io.ReadAll(stderr)
-	if stderrError != nil {
-		return data, stdoutError
-	}
-	cmd.Wait()
-	errorMessage := strings.TrimSpace(string(errorBytes))
-	if len(errorMessage) > 0 {
-		return data, errors.New(errorMessage)
-	}
-	loggo.DebugTimed("successfully scaled image", timestamp, "image: "+image, "resolution: "+config.Resolution, "size: "+strconv.Itoa(len(data)))
-	return data, nil
-}

internal/slideshow/slideshow.go

@@ -1,138 +0,0 @@
-package slideshow
-
-import (
-	"errors"
-	"image/color"
-	"io"
-	"os/exec"
-	"strconv"
-	"strings"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-	"git.velvettear.de/velvettear/slideshow/scanner"
-)
-
-// remember last shown image
-var previousImage string
-
-// start the slideshow
-func Start() {
-	loggo.Info("starting the image slideshow...", "interval: "+strconv.FormatFloat(config.Interval.Seconds(), 'f', 0, 64)+" seconds")
-	var sleepTime time.Duration
-	var scaleTime time.Duration
-	scaleImages := config.IsResolutionSet()
-	for {
-		var image string
-		var palette []color.Color
-		var data []byte
-		for {
-			image = scanner.GetRandomImage()
-			if image != previousImage {
-				break
-			}
-		}
-		if scaleImages {
-			scaleTimestamp := time.Now()
-			tmp, error := scale(image)
-			if error != nil {
-				loggo.Error("encountered an error scaling an image", "image: "+image, error.Error())
-				continue
-			}
-			data = tmp
-			scaleTime = time.Since(scaleTimestamp)
-			palette, _ = getColorPaletteRaw(data)
-		} else {
-			palette, _ = getColorPalette(image)
-		}
-		if sleepTime > 0 {
-			loggo.Debug("sleeping for " + strconv.FormatInt(sleepTime.Milliseconds(), 10) + "ms before next image will be displayed...")
-			time.Sleep(sleepTime)
-		}
-		go exportPalette(palette)
-		if scaleImages {
-			error := setBackgroundPiped(data)
-			if error != nil {
-				loggo.Error("encountered an error setting the background via pipe to feh's stdin", error.Error())
-			}
-			loggo.Info("set new scaled background image", "image: "+image, "resolution: "+config.Resolution)
-		} else {
-			error := setBackgroundImage(image)
-			if error != nil {
-				loggo.Error("encountered an error setting the background image", "image: "+image, error.Error())
-			}
-			loggo.Info("set new background image", "image: "+image)
-		}
-		sleepTime = config.Interval - scaleTime
-	}
-}
-
-// set the background image via 'feh'
-func setBackgroundImage(image string) error {
-	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", image)
-	stdout, stdoutError := cmd.StdoutPipe()
-	stderr, stderrError := cmd.StderrPipe()
-	cmd.Start()
-	if stdoutError != nil {
-		return stdoutError
-	}
-	if stderrError != nil {
-		return stderrError
-	}
-	_, stdoutError = io.ReadAll(stdout)
-	if stdoutError != nil {
-		return stdoutError
-	}
-	errorBytes, stderrError := io.ReadAll(stderr)
-	if stderrError != nil {
-		return stderrError
-	}
-	cmd.Wait()
-	error := strings.TrimSpace(string(errorBytes))
-	if len(error) > 0 {
-		return errors.New(error)
-	}
-	return nil
-}
-
-// pipe data to 'feh' via stdin to set the background image
-func setBackgroundPiped(data []byte) error {
-	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", "-")
-	stdin, stdinError := cmd.StdinPipe()
-	stdout, stdoutError := cmd.StdoutPipe()
-	stderr, stderrError := cmd.StderrPipe()
-	cmd.Start()
-	if stdinError != nil {
-		return stdinError
-	}
-	if stdoutError != nil {
-		return stdoutError
-	}
-	if stderrError != nil {
-		return stderrError
-	}
-	defer stdin.Close()
-	defer stdout.Close()
-	defer stderr.Close()
-	_, stdinError = stdin.Write(data)
-	if stdinError != nil {
-		return stdinError
-	} else {
-		stdin.Close()
-	}
-	_, stdoutError = io.ReadAll(stdout)
-	if stdoutError != nil {
-		return stdoutError
-	}
-	errorBytes, stderrError := io.ReadAll(stderr)
-	if stderrError != nil {
-		return stderrError
-	}
-	cmd.Wait()
-	error := strings.TrimSpace(string(errorBytes))
-	if len(error) > 0 {
-		return errors.New(error)
-	}
-	return nil
-}

internal/streams.go

@@ -0,0 +1,73 @@
+package internal
+
+import (
+	"errors"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+	"time"
+
+	"git.velvettear.de/velvettear/loggo"
+)
+
+// pipe data from a stream to 'feh'
+func streamToFeh(stream io.ReadCloser) error {
+	timestamp := time.Now().UnixMilli()
+	defer stream.Close()
+	cmd := exec.Command("feh", "--no-fehbg", "--bg-fill", "-")
+	stdin, stdinError := cmd.StdinPipe()
+	if stdinError != nil {
+		return stdinError
+	}
+	defer stdin.Close()
+	stdout, stdoutError := cmd.StdoutPipe()
+	if stdoutError != nil {
+		return stdoutError
+	}
+	defer stdout.Close()
+	stderr, stderrError := cmd.StderrPipe()
+	if stderrError != nil {
+		return stderrError
+	}
+	defer stderr.Close()
+	cmd.Start()
+	written, copyError := io.Copy(stdin, stream)
+	if copyError != nil {
+		return copyError
+	}
+	if written == 0 {
+		_, stdoutError = io.ReadAll(stdout)
+		if stdoutError != nil {
+			return stdoutError
+		}
+		errorBytes, stderrError := io.ReadAll(stderr)
+		if stderrError != nil {
+			return stderrError
+		}
+		error := strings.TrimSpace(string(errorBytes))
+		if len(error) > 0 {
+			return errors.New(error)
+		}
+	}
+	stdin.Close()
+	cmd.Wait()
+	loggo.DebugTimed("successfully piped the data stream to 'feh''", timestamp, "size: "+FormatBytes(written))
+	return nil
+}
+
+// write data from a stream to a file
+func streamToFile(stream io.ReadCloser, path string) error {
+	timestamp := time.Now().UnixMilli()
+	defer stream.Close()
+	file, error := os.Create(path)
+	if error != nil {
+		return error
+	}
+	written, error := io.Copy(file, stream)
+	if error != nil {
+		return error
+	}
+	loggo.DebugTimed("successfully piped the data stream to file '"+path+"'", timestamp, "size: "+FormatBytes(written))
+	return nil
+}

main.go

@@ -1,23 +1,17 @@
 package main
 
 import (
-	"sync"
 	"time"
 
 	"git.velvettear.de/velvettear/loggo"
+	"git.velvettear.de/velvettear/slideshow/internal"
 	"git.velvettear.de/velvettear/slideshow/internal/config"
-	"git.velvettear.de/velvettear/slideshow/internal/slideshow"
-	"git.velvettear.de/velvettear/slideshow/scanner"
 )
 
 func main() {
 	timestamp := time.Now().UnixMilli()
 	loggo.Info("slideshow is starting now...")
-	var waitgroup sync.WaitGroup
-	waitgroup.Add(1)
 	config.Initialize()
-	scanner.Initialize()
+	internal.StartSlideshow()
-	slideshow.Start()
-	waitgroup.Wait()
 	loggo.InfoTimed("slideshow is shutting down now!", timestamp)
 }

scanner/scanner.go

@@ -1,66 +0,0 @@
-package scanner
-
-import (
-	"io/fs"
-	"math/rand"
-	"path/filepath"
-	"strconv"
-	"strings"
-	"time"
-
-	"git.velvettear.de/velvettear/loggo"
-	"git.velvettear.de/velvettear/slideshow/internal/config"
-)
-
-// slice of images
-var images []string
-
-// temporary slice of images
-var tmpImages []string
-
-// scan the specified directories for images
-func Initialize() {
-	directory := config.Directory
-	scan(directory)
-}
-
-// get a random image
-func GetRandomImage() string {
-	return images[rand.Intn(len(images))]
-}
-
-// scan the specified directory
-func scan(directory string) {
-	timestamp := time.Now().UnixMilli()
-	loggo.Info("scanning directory for images and subdirectories...", "interval: "+strconv.FormatFloat(config.ScanInterval.Seconds(), 'f', 0, 64)+" seconds", "directory: "+directory)
-	filepath.WalkDir(directory, checkDirectory)
-	images = tmpImages
-	tmpImages = nil
-	loggo.InfoTimed("found "+strconv.Itoa(len(images))+" image(s)", timestamp)
-	go scheduleRescan(directory)
-}
-
-// sleep the specified interval and then trigger a rescan of the specified directory
-func scheduleRescan(directory string) {
-	loggo.Debug("sleeping for " + strconv.FormatInt(config.ScanInterval.Milliseconds(), 10) + "ms before next scan...")
-	time.Sleep(config.ScanInterval)
-	scan(directory)
-}
-
-// add image files to the slice of images and subdirectoies to the watcher
-func checkDirectory(path string, dir fs.DirEntry, err error) error {
-	if err != nil {
-		return err
-	}
-	if dir.IsDir() || !isImage(path) {
-		return nil
-	}
-	tmpImages = append(tmpImages, path)
-	loggo.Debug("added image to temporary slice of images", path)
-	return nil
-}
-
-// check if a file is an image
-func isImage(file string) bool {
-	return strings.HasSuffix(file, ".jpeg") || strings.HasSuffix(file, ".jpg") || strings.HasSuffix(file, ".png")
-}

slideshow.service

@@ -5,14 +5,17 @@ Description=slideshow
 Type=simple
 User=velvettear
 Environment="DISPLAY=:0"
+ENVIRONMENT="SLIDESHOW_API=localhost:3000"
 Environment="SLIDESHOW_INTERVAL=60"
-Environment="SLIDESHOW_DIRECTORY=$HOME"
+Environment="SLIDESHOW_RESOLUTION="
-Environment="SLIDESHOW_SCANINTERVAL=60"
-Environment="SLIDESHOW_RESOLUTION=1920x1080"
-Environment="SLIDESHOW_LOGLEVEL=info"
 Environment="SLIDESHOW_PALETTE=/tmp/.slideshow.palette"
-Environment="SLIDESHOW_PALETTE_ALGORITHM=wsm"
+Environment="SLIDESHOW_PALETTE_ALGORITHM="
-Environment="SLIDESHOW_PALETTE_COLORS=16"
+Environment="SLIDESHOW_PALETTE_COLORS="
+Environment="SLIDESHOW_SCRIPT="
+Environment="SLIDESHOW_SCRIPT_ARGS="
+Environment="SLIDESHOW_SCRIPT_ASYNC="
+Environment="SLIDESHOW_SCRIPT_STAGE="
+Environment="SLIDESHOW_LOGLEVEL=debug"
 ExecStart=/opt/slideshow/slideshow
 
 [Install]