Github user StephanEwen commented on a diff in the pull request:
https://github.com/apache/flink/pull/1524#discussion_r51123709
--- Diff: flink-core/src/main/java/org/apache/flink/core/fs/FileSystem.java
---
@@ -159,56 +163,109 @@ public int hashCode() {
/**
* Returns a reference to the {@link FileSystem} instance for accessing
the
* local file system.
- *
+ *
* @return a reference to the {@link FileSystem} instance for accessing
the
- * local file system.
+ * local file system.
*/
public static FileSystem getLocalFileSystem() {
// this should really never fail.
try {
URI localUri = OperatingSystem.isWindows() ? new
URI("file:/") : new URI("file:///");
return get(localUri);
- }
- catch (Exception e) {
+ } catch (Exception e) {
throw new RuntimeException("Cannot create URI for local
file system");
}
}
/**
+ * The default filesystem scheme to be used. This can be specified by
the parameter
+ * <code>fs.default-scheme</code> in <code>flink-conf.yaml</code>. By
default this is
+ * set to <code>file:///</code> (see {@link
ConfigConstants#FILESYSTEM_SCHEME}
+ * and {@link ConfigConstants#DEFAULT_FILESYSTEM_SCHEME}), and uses the
local filesystem.
+ */
+ private static URI defaultScheme;
+
+ /**
+ * <p>Sets the default filesystem scheme based on the user-specified
configuration parameter
+ * <code>fs.default-scheme</code>. By default this is set to
<code>file:///</code>
+ * (see {@link ConfigConstants#FILESYSTEM_SCHEME} and
+ * {@link ConfigConstants#DEFAULT_FILESYSTEM_SCHEME}),
+ * and the local filesystem is used.
+ * <p>
+ * As an example, if set to <code>hdfs://localhost:9000/</code>, then
an HDFS deployment
+ * with the namenode being on the local node and listening to port 9000
is going to be used.
+ * In this case, a file path specified as
<code>/user/USERNAME/in.txt</code>
+ * is going to be transformed into
<code>hdfs://localhost:9000/user/USERNAME/in.txt</code>. By
+ * default this is set to <code>file:///</code> which points to the
local filesystem.
+ * @param config the configuration from where to fetch the parameter.
+ */
+ public static void setDefaultScheme(Configuration config) throws
IOException {
+ synchronized (SYNCHRONIZATION_OBJECT) {
+ if (defaultScheme == null) {
+ String stringifiedUri =
config.getString(ConfigConstants.FILESYSTEM_SCHEME,
+
ConfigConstants.DEFAULT_FILESYSTEM_SCHEME);
+ try {
+ defaultScheme = new URI(stringifiedUri);
+ } catch (URISyntaxException e) {
+ throw new IOException("The URI used to
set the default filesystem " +
+ "scheme ('" + stringifiedUri +
"') is not valid.");
+ }
+ }
+ }
+ }
+
+ /**
+ * <p><b>ATTENTION:</b> this method is only used in tests.</p>
+ * <p>Clears the previously set <code>fs.default-scheme</code>
+ * (see {@link ConfigConstants#FILESYSTEM_SCHEME})</p>
+ */
+ public static void clearDefaultScheme() {
--- End diff --
This should not be public. Users do not read comments and simply call this.
The tests probably need a custom reflection cleaner to reset that.
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