Some docs and cleanup

README.md

@@ -1,12 +1,104 @@
 # traefik-lazyloader
 
-Takes advantage of traefik's router priority to proxy to this small application that will manage
+This small app will automatically start and stop docker containers based on access, for instance,
-starting/stopping containers to save resources.
+via traefik.
+
+## How it Works
+
+It works by acting as the fallback-route for the containers. For instance, if you have
+`example.com` as a container you want to lazy-load, you would add the container, as well
+as this lazyloader that would act as a lower-priority router for the same domain. If the
+host is accessed, the lazyloader will work to boot up the container and redirect the user
+as soon as it's up.
+
+It then monitors the container's network interface. If the network is idle for X minutes, it
+will stop the container.
 
 ## Quick-Start
 
+### docker-compose
+```yaml
+version: '3.5'
+
+services:
+  reverse-proxy:
+    image: traefik:v2.4
+    command:
+      - --api.insecure
+      - --providers.docker
+      - --providers.docker.defaultRule=Host(`{{.Name}}.example.com`)
+      - --entryPoints.web.address=:80
+      - --entryPoints.web.forwardedHeaders.insecure
+      - --providers.docker.exposedByDefault=false
+    restart: always
+    ports:
+      - "80:80"     # The HTTP port
+      - "8080:8080" # The Web UI (enabled by --api)
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock # So that Traefik can listen to the Docker events
+
+  lazyloader:
+    build: .
+    labels:
+      - traefik.enable=true
+      - "traefik.http.routers.lazyload.priority=-100" # Lower router priority. Would only be hit if the app isn't running
+      - "traefik.http.routers.lazyload.rule=Host(`whoami.example.com`, `lazyloader.example.com`)"
+    environment:
+      TLL_STOPATBOOT: true                   # Stop all lazyloaded containers at boot (great for an example)
+      TLL_STATUSHOST: lazyloader.example.com # This hostname will display a status page. Disabled by default
+    networks:
+      - traefik-bridge
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock # Must access docker
+
+  whoami:
+    image: containous/whoami
+    networks:
+      - traefik-bridge
+    labels:
+      - traefik.enable=true
+      - "traefik.http.routers.lazywhoami.rule=Host(`whoami.example.com`)"
+      - lazyloader=true
+      - lazyloader.stopdelay=30s # Overrides the default
+
+networks:
+  traefik-bridge:
+    external: true
+    name: traefik-bridge
+```
+
+You can run `docker-compose up` on the above for a quick-start. You will need to alter the domains as needed.
+
 ## Config
 
+Configuration uses [viper]() and can be specified by either overwriting the `config.yaml` file or
+via environment variables with the `TLL_` prefix (Traefik lazy loader)
+
+```yaml
+# What port to listen on
+listen: :8080
+
+# If set, when access via this hostname, will display status page
+statushost: ""
+
+# Enable debug logging
+verbose: false
+
+# if true, will stop all running tagged containers when the lazyloader starts
+stopatboot: false
+
+# which splash-page asset to use
+splash: splash.html
+
+# Container defaults
+stopdelay: 5m # How long to wait before stopping container
+pollfreq: 10s # How often to check
+
+# This will be the label-prefix to look at settings on a container
+# usually won't need to change (only if running multiple instances)
+labelprefix: lazyloader
+```
+
 ## Labels
 
 * `lazyloader=true` -- (Required) Add to containers that should be managed

config.yaml

@@ -1,11 +1,22 @@
+# What port to listen on
 listen: :8080
 
-stopatboot: false
+# If set, when access via this hostname, will display status page
-splash: splash.html
-
-stopdelay: 5m
-pollfreq: 10s
 statushost: ""
+
+# Enable debug logging
 verbose: false
 
+# if true, will stop all running tagged containers when the lazyloader starts
+stopatboot: false
+
+# which splash-page asset to use
+splash: splash.html
+
+# Container defaults
+stopdelay: 5m # How long to wait before stopping container
+pollfreq: 10s # How often to check
+
+# This will be the label-prefix to look at settings on a container
+# usually won't need to change (only if running multiple instances)
 labelprefix: lazyloader

main.go

@@ -94,7 +94,7 @@ func StatusHandler(w http.ResponseWriter, r *http.Request) {
 		runtime.ReadMemStats(&stats)
 		statusPageTemplate.Execute(w, StatusPageModel{
 			Active:         core.ActiveContainers(),
-			Qualifying:     core.QualifyingContainers(),
+			Qualifying:     core.QualifyingContainers(r.Context()),
 			RuntimeMetrics: fmt.Sprintf("Heap=%d, InUse=%d, Total=%d, Sys=%d, NumGC=%d", stats.HeapAlloc, stats.HeapInuse, stats.TotalAlloc, stats.Sys, stats.NumGC),
 		})
 	default:

pkg/service/service.go

@@ -74,7 +74,6 @@ func (s *Core) StartHost(hostname string) (*StartResult, error) {
 	}
 
 	if ets, exists := s.active[ct.ID]; exists {
-		// TODO: Handle case we think it's active, but not? (eg. crash? slow boot?)
 		logrus.Debugf("Asked to start host, but we already think it's started: %s", ets.name)
 		return &StartResult{
 			WaitForCode: ets.waitForCode,
@@ -265,6 +264,7 @@ func (s *Core) findAllLazyloadContainers(ctx context.Context, includeStopped boo
 	})
 }
 
+// Returns all actively managed containers
 func (s *Core) ActiveContainers() []*ContainerState {
 	s.mux.Lock()
 	defer s.mux.Unlock()
@@ -279,8 +279,9 @@ func (s *Core) ActiveContainers() []*ContainerState {
 	return ret
 }
 
-func (s *Core) QualifyingContainers() []string {
+// Return all containers that qualify to be load-managed (eg. have the tag)
-	ct, err := s.findAllLazyloadContainers(context.Background(), true)
+func (s *Core) QualifyingContainers(ctx context.Context) []string {
+	ct, err := s.findAllLazyloadContainers(ctx, true)
 	if err != nil {
 		return nil
 	}

pkg/service/util.go

@@ -2,6 +2,7 @@ package service
 
 import (
 	"fmt"
+	"strings"
 	"traefik-lazyload/pkg/config"
 
 	"github.com/docker/docker/api/types"
@@ -22,7 +23,7 @@ func labelOrDefault(ct *types.Container, sublabel, dflt string) (string, bool) {
 	return dflt, false
 }
 
-func short(id string) string {
+func shortId(id string) string {
 	const SLEN = 8
 	if len(id) <= SLEN {
 		return id
@@ -33,11 +34,18 @@ func short(id string) string {
 func containerShort(c *types.Container) string {
 	var name string
 	if len(c.Names) > 0 {
-		name = c.Names[0]
+		name = trimRootPath(c.Names[0])
 	} else {
 		name = c.Image
 	}
-	return fmt.Sprintf("%s(%s)", name, short(c.ID))
+	return fmt.Sprintf("%s(%s)", name, shortId(c.ID))
+}
+
+func trimRootPath(s string) string {
+	if strings.HasPrefix(s, "/") {
+		return s[1:]
+	}
+	return s
 }
 
 func isRunning(c *types.Container) bool {