GTC-2823 Fix retries when getting latest version of a dataset

I noticed that the retry code in RasterCatalog.getLatestVersion was not
correct. It was using recursion to do one or more retries, but wasn't
actually using any successful response from a retry, but instead still
used the original unsuccessful response. Broke out a separate function
getLatestVersionResponse() to fix the problem. I am still doing 2 more
retries after the first request.

Also, increased the connection timeout from 10 seconds to 20 seconds.

These fixes should make Geotrellis more resilient to slow responses from
the Data API. With a bigger change, I could also get rid of the "latest
version" requests for FCD and AFI analyses, since they don't actually use
the integrated alerts dataset.

src/main/scala/org/globalforestwatch/config/RasterCatalog.scala

@@ -71,24 +71,35 @@ object RasterCatalog {
     }
   }
 
-  def getLatestVersion(dataset: String, retries: Int = 0): String = {
+  // Internal function to do a "latest" request to the Data API, doing retries
+  // recursively as necessary. Return the JSON response. Throws an exception if there
+  // was no successful response.
+  def getLatestVersionResponse(dataset: String, retries: Int = 0): HttpResponse[String] = {
     val response: HttpResponse[String] = Http(
       s"https://data-api.globalforestwatch.org/dataset/${dataset}/latest"
     ).option(HttpOptions
       .followRedirects(true))
-      .option(HttpOptions.connTimeout(10000))
+      .option(HttpOptions.connTimeout(20000))
       .option(HttpOptions.readTimeout(50000)).asString
 
-    if (!response.isSuccess) {
-      if (retries <= 2) {
-        Thread.sleep(10000)
-        getLatestVersion(dataset, retries + 1)
-      } else {
-        throw new IllegalArgumentException(
-          s"Dataset ${dataset} has no latest version or does not exist. Data API response code: ${response.code}"
-        )
-      }
+    if (response.isSuccess) {
+      response
+    } else if (retries > 2) {
+      // Do 3 total tries to get a successful response, then throw an exception.
+      throw new IllegalArgumentException(
+        s"Problem accessing latest version of dataset ${dataset}. Data API response code: ${response.code}"
+      )
+    } else {
+      // Sleep for ten seconds and then return any successful retry.
+      Thread.sleep(10000)
+      getLatestVersionResponse(dataset, retries + 1)
     }
+  }
+
+  /** Get the latest version of a dataset, by calling the Data API.  Do several retries if there are errors.
+    */
+  def getLatestVersion(dataset: String): String = {
+    val response = getLatestVersionResponse(dataset)
 
     val json: Map[String, Any] = jsonStrToMap(response.body)