fabric: retry loader version lookup (#543)

Author: itzg

src/main/java/me/itzg/helpers/McImageHelper.java

@@ -239,4 +239,4 @@ public Integer call() throws Exception {
             return ExitCode.OK;
         }
     }
-}
+}

src/main/java/me/itzg/helpers/fabric/FabricMetaClient.java

@@ -19,6 +19,18 @@ public class FabricMetaClient {
 
     private final SharedFetch sharedFetch;
     private final UriBuilder uriBuilder;
+
+    /**
+     * Retry attempts for metadata, non-downloads
+     */
+    @Setter
+    private long retryMaxAttempts = 5;
+    /**
+     * Retry minimum backoff for metadata, non-downloads
+     */
+    @Setter
+    private Duration retryMinBackoff = Duration.ofMillis(500);
+
     @Setter
     private int downloadRetryMaxAttempts = 5;
     @Setter
@@ -59,7 +71,9 @@ else if (isSnapshot(version)) {
                     return findFirst(versionEntries, versionEntry -> versionEntry.getVersion().equalsIgnoreCase(version))
                         .switchIfEmpty(Mono.error(() -> new GenericException("Unable to find requested version")));
                 }
-            });
+            })
+            .retryWhen(Retry.backoff(retryMaxAttempts, retryMinBackoff).filter(IOException.class::isInstance))
+            .checkpoint();
     }
 
     private static boolean isSnapshot(@Nullable String version) {
@@ -91,7 +105,9 @@ public Mono<String> resolveLoaderVersion(String minecraftVersion, String loaderV
                     .getLoader();
 
                 return Mono.just(loader.getVersion());
-            });
+            })
+            .retryWhen(Retry.backoff(retryMaxAttempts, retryMinBackoff).filter(IOException.class::isInstance))
+            .checkpoint();
     }
 
     public Mono<String> resolveInstallerVersion(String installerVersion) {
@@ -111,7 +127,9 @@ public Mono<String> resolveInstallerVersion(String installerVersion) {
                 .orElseGet(
                     () -> Mono.error(new GenericException("Failed to find stable installer from " + uriBuilder.getBaseUrl()))
                 )
-            );
+            )
+            .retryWhen(Retry.backoff(retryMaxAttempts, retryMinBackoff).filter(IOException.class::isInstance))
+            .checkpoint();
     }
 
     public Mono<Path> downloadLauncher(

src/main/java/me/itzg/helpers/http/ObjectFetchBuilder.java

@@ -2,17 +2,15 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectReader;
+import java.io.IOException;
+import java.util.List;
 import lombok.extern.slf4j.Slf4j;
-import me.itzg.helpers.errors.GenericException;
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
 import reactor.netty.ByteBufMono;
 import reactor.netty.http.client.HttpClient;
 import reactor.netty.http.client.HttpClientResponse;
 
-import java.io.IOException;
-import java.util.List;
-
 @Slf4j
 public class ObjectFetchBuilder<T> extends FetchBuilderBase<ObjectFetchBuilder<T>>
     implements RequestResponseAssembler<T>
@@ -84,7 +82,7 @@ private <R> Mono<R> handleResponse(HttpClientResponse resp, ByteBufMono bodyMono
                     try {
                         return Mono.just(reader.readValue(inputStream));
                     } catch (IOException e) {
-                        return Mono.error(new GenericException(
+                        return Mono.error(new ResponseParsingException(
                             "Failed to parse response body into " +
                                 (listOf ? "list of " + type : type),
                             e

src/main/java/me/itzg/helpers/http/ResponseParsingException.java

@@ -0,0 +1,10 @@
+package me.itzg.helpers.http;
+
+import java.io.IOException;
+
+public class ResponseParsingException extends IOException {
+
+    public ResponseParsingException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/me/itzg/helpers/modrinth/ModrinthApiClient.java

@@ -31,6 +31,9 @@
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
 
+/**
+ * Provides a client for <a href="https://docs.modrinth.com/api/">Modrinth Labrinth API</a>
+ */
 @Slf4j
 public class ModrinthApiClient implements AutoCloseable {
 

src/main/java/me/itzg/helpers/modrinth/model/VersionFile.java

@@ -3,13 +3,20 @@
 import java.util.Map;
 import lombok.Data;
 
+/**
+ * Refer to <code>files</code> of <a href="https://docs.modrinth.com/api/operations/getversion/#200">getversion</a>
+ */
 @Data
 public class VersionFile {
-  Map<String,String> hashes;
 
-  String url;
+    /**
+     * key is either sha512 or sha1
+     */
+    Map<String, String> hashes;
 
-  String filename;
+    String url;
 
-  boolean primary;
+    String filename;
+
+    boolean primary;
 }