mc: added debug-ability to vanilla server downloading

minecraft-server/start-deployVanilla

@@ -1,10 +1,42 @@
 #!/bin/bash
 
+. /start-utils
+set -o pipefail
+
 export SERVER="minecraft_server.$VANILLA_VERSION.jar"
 
 if [ ! -e $SERVER ]; then
   echo "Downloading $SERVER ..."
-  curl -sSL -o $SERVER $(curl -s $(curl -s 'https://launchermeta.mojang.com/mc/game/version_manifest.json' | jq --arg VANILLA_VERSION "$VANILLA_VERSION" --raw-output '[.versions[]|select(.id == $VANILLA_VERSION)][0].url') | jq --raw-output '.downloads.server.url')
+  debug "Finding version manifest for $VANILLA_VERSION"
+  versionManifestUrl=$(curl -fsSL 'https://launchermeta.mojang.com/mc/game/version_manifest.json' | jq --arg VANILLA_VERSION "$VANILLA_VERSION" --raw-output '[.versions[]|select(.id == $VANILLA_VERSION)][0].url')
+  result=$?
+  if [ $result != 0 ]; then
+    echo "ERROR failed to obtain version manifest URL ($result)"
+    exit 1
+  fi
+  if [ $versionManifestUrl = "null" ]; then
+    echo "ERROR couldn't find a matching manifest entry for $VANILLA_VERSION"
+    exit 1
+  fi
+  debug "Found version manifest at $versionManifestUrl"
+
+  serverDownloadUrl=$(curl -fsSL ${versionManifestUrl} | jq --raw-output '.downloads.server.url')
+  result=$?
+  if [ $result != 0 ]; then
+    echo "ERROR failed to obtain version manifest from $versionManifestUrl ($result)"
+    exit 1
+  fi
+
+  debug "Downloading server from $serverDownloadUrl"
+  if isDebugging; then
+    verbose=-v
+  fi
+  curl $verbose -fsSL -o $SERVER $serverDownloadUrl
+  result=$?
+  if [ $result != 0 ]; then
+    echo "ERROR failed to download server from $serverDownloadUrl ($result)"
+    exit 1
+  fi
 fi
 
 # Continue to Final Setup

minecraft-server/start-utils

@@ -25,4 +25,18 @@ function isTrue {
   esac
 
   return ${result}
+}
+
+function isDebugging {
+  if [ ${DEBUG^^} = TRUE ]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+function debug {
+  if isDebugging; then
+    echo "DEBUG: $*"
+  fi
 }