feat(streamer): backport autofallback from transcoder

Author: uZer

example/liquidsoap/mystreamer.liq

@@ -4,33 +4,30 @@ streamer_name = "mystreamer"
 harbor_http_port = 7020
 prometheus_server_port = 9021
 liquidsoap_log_level = 3
-
-# tmp
-input_playlist_file = "/audio/lib/#{streamer_name}.m3u"
+livesource_state_path = "/state/#{streamer_name}.livesourcestate"
 
 input_list =
   [
     {
       name="voieA",
-      kind=fun (input_kinds) -> input_kinds.restream,
+      kind="restream",
       input="udp://228.0.6.102:1026",
-      is_autofallback=true,
-      priority=100
+      playlist_file="",
+      is_autofallback=true
     },
     {
       name="voieB",
-      kind=fun (input_kinds) -> input_kinds.restream,
+      kind="restream",
       input="./example/liquidsoap/mystreamer-voieB.sdp",
       input_options="protocol_whitelist='file,udp,rtp'",
-      is_autofallback=true,
-      priority=101
+      playlist_file="",
+      is_autofallback=true
     },
     {
       name="localPlaylist",
-      kind=fun (input_kinds) -> input_kinds.playlist,
+      kind="playlist",
       playlist_file="/audio/lib/#{streamer_name}.m3u",
-      is_autofallback=true,
-      priority=102
+      is_autofallback=true
     }
   ]
 

scripts/streamer/00-live.liq

@@ -1,9 +1,13 @@
 #!/usr/bin/liquidsoap
 
 %include "10-settings.liq"
-%include "20-prometheus.liq"
 
-%include "inputs/playlist.liq"
+# We define the default preferred_live_source (for the switch "live" defined
+# later on) as being the first input in the input_list. We need to do that here,
+# so we can define update_source_metrics callback in 20-prometheus.liq
+preferred_live_source = ref(list.nth(input_list, 0).name)
 
+%include "20-prometheus.liq"
+%include "50-inputs.liq"
 %include "80-outputs.liq"
 %include "90-http.liq"

scripts/streamer/50-inputs.liq

@@ -0,0 +1,56 @@
+# Inputs
+
+input_sources = []
+
+%include "inputs/playlist.liq"
+
+def is_playing(n) =
+  fun () -> n == preferred_live_source()
+end
+
+def mk_switch_source(s) =
+  (is_playing(s.name), s.source)
+end
+
+def mk_fallback_source(result, s) =
+  if
+    s.is_autofallback
+  then
+    [...result, (s.source : source(audio=pcm))]
+  else
+    result
+  end
+end
+
+# get the livesourcestate on disk if it exist
+if
+  file.exists(livesource_state_path)
+then
+  content = file.contents(livesource_state_path)
+
+  # check that the livesource exist in input list
+  if
+    list.exists(fun (s) -> s.name == content, input_sources)
+  then
+    preferred_live_source := content
+  end
+end
+
+real_live_source = ref("")
+
+live =
+  switch(
+    id="switch_live",
+    track_sensitive=false,
+    list.map(mk_switch_source, input_sources)
+  )
+
+radio =
+  fallback(
+    id="fallback_prod",
+    track_sensitive=false,
+    [
+      (live : source(audio=pcm)),
+      ...list.fold(mk_fallback_source, [], input_sources)
+    ]
+  )

scripts/streamer/inputs/playlist.liq

@@ -1,4 +1,13 @@
-# Build the playlist
-radio = playlist(input_playlist_file)
-radio = mksafe(id="playlist", radio)
-radio = crossfade(fade_out=3., fade_in=3., duration=5., radio)
+# Build inputs of kind playlist
+
+def mk_playlist_source(s) =
+  let {name, playlist_file} = s
+  radio = playlist(playlist_file)
+  radio = mksafe(id="#{name}", radio)
+  radio = crossfade(fade_out=3., fade_in=3., duration=5., radio)
+  radio
+end
+
+input_list_playlists = list.filter(fun (i) -> i.kind == "playlist", input_list)
+
+list.append(input_sources, list.map(mk_playlist_source, input_list_playlists))