Access to public S3 buckets without credentials

doc/changes/changes_2.7.8.md

@@ -0,0 +1,11 @@
+# Cloud Storage Extension 2.7.8, released 2023-11-10
+
+Code name: Access to public S3 buckets without credentials
+
+## Summary
+
+Implemented an option to access public S3 buckets without credentials.
+
+## Features
+
+* #283: Support publicly available S3 buckets without credentials

doc/user_guide/user_guide.md

@@ -150,7 +150,7 @@ downloaded jar file is the same as the checksum provided in the releases.
 To check the SHA256 result of the local jar, run the command:
 
 ```sh
-sha256sum exasol-cloud-storage-extension-2.7.7.jar
+sha256sum exasol-cloud-storage-extension-2.7.8.jar
 ```
 
 ### Building From Source
@@ -180,7 +180,7 @@ mvn clean package -DskipTests=true
 ```
 
 The assembled jar file should be located at
-`target/exasol-cloud-storage-extension-2.7.7.jar`.
+`target/exasol-cloud-storage-extension-2.7.8.jar`.
 
 ### Create an Exasol Bucket
 
@@ -202,7 +202,7 @@ for the HTTP protocol.
 Upload the jar file using curl command:
 
 ```sh
-curl -X PUT -T exasol-cloud-storage-extension-2.7.7.jar \
+curl -X PUT -T exasol-cloud-storage-extension-2.7.8.jar \
   http://w:<WRITE_PASSWORD>@exasol.datanode.domain.com:2580/<BUCKET>/
 ```
 
@@ -234,7 +234,7 @@ OPEN SCHEMA CLOUD_STORAGE_EXTENSION;
 
 CREATE OR REPLACE JAVA SET SCRIPT IMPORT_PATH(...) EMITS (...) AS
   %scriptclass com.exasol.cloudetl.scriptclasses.FilesImportQueryGenerator;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 
 CREATE OR REPLACE JAVA SCALAR SCRIPT IMPORT_METADATA(...) EMITS (
@@ -244,12 +244,12 @@ CREATE OR REPLACE JAVA SCALAR SCRIPT IMPORT_METADATA(...) EMITS (
   end_index DECIMAL(36, 0)
 ) AS
   %scriptclass com.exasol.cloudetl.scriptclasses.FilesMetadataReader;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 
 CREATE OR REPLACE JAVA SET SCRIPT IMPORT_FILES(...) EMITS (...) AS
   %scriptclass com.exasol.cloudetl.scriptclasses.FilesDataImporter;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 ```
 
@@ -268,12 +268,12 @@ OPEN SCHEMA CLOUD_STORAGE_EXTENSION;
 
 CREATE OR REPLACE JAVA SET SCRIPT EXPORT_PATH(...) EMITS (...) AS
   %scriptclass com.exasol.cloudetl.scriptclasses.TableExportQueryGenerator;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 
 CREATE OR REPLACE JAVA SET SCRIPT EXPORT_TABLE(...) EMITS (ROWS_AFFECTED INT) AS
   %scriptclass com.exasol.cloudetl.scriptclasses.TableDataExporter;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 ```
 
@@ -407,13 +407,13 @@ CREATE OR REPLACE JAVA SCALAR SCRIPT IMPORT_METADATA(...) EMITS (
 ) AS
   %jvmoption -DHTTPS_PROXY=http://username:[email protected]:1180
   %scriptclass com.exasol.cloudetl.scriptclasses.FilesMetadataReader;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 
 CREATE OR REPLACE JAVA SET SCRIPT IMPORT_FILES(...) EMITS (...) AS
   %jvmoption -DHTTPS_PROXY=http://username:[email protected]:1180
   %scriptclass com.exasol.cloudetl.scriptclasses.FilesDataImporter;
-  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.7.jar;
+  %jar /buckets/bfsdefault/<BUCKET>/exasol-cloud-storage-extension-2.7.8.jar;
 /
 ```
 
@@ -722,6 +722,10 @@ S3_SESSION_TOKEN
 Please follow the [Amazon credentials management best practices][aws-creds] when
 creating credentials.
 
+If you are accessing the public bucket, you don't need credentials. In such case,
+you need to set `S3_ACCESS_KEY` and `S3_SECRET_KEY` to empty values:
+`S3_ACCESS_KEY=;S3_SECRET_KEY=`.
+
 [aws-creds]: https://docs.aws.amazon.com/general/latest/gr/aws-sec-cred-types.html
 
 Another required parameter is the S3 endpoint, `S3_ENDPOINT`. An endpoint is the

pom.xml

@@ -3,14 +3,14 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.exasol</groupId>
     <artifactId>cloud-storage-extension</artifactId>
-    <version>2.7.7</version>
+    <version>2.7.8</version>
     <name>Cloud Storage Extension</name>
     <description>Exasol Cloud Storage Import And Export Extension</description>
     <url>https://github.com/exasol/cloud-storage-extension/</url>
     <parent>
         <artifactId>cloud-storage-extension-generated-parent</artifactId>
         <groupId>com.exasol</groupId>
-        <version>2.7.7</version>
+        <version>2.7.8</version>
         <relativePath>pk_generated_parent.pom</relativePath>
     </parent>
     <properties>

src/main/scala/com/exasol/cloudetl/bucket/S3Bucket.scala

@@ -52,6 +52,9 @@ final case class S3Bucket(path: String, params: StorageProperties) extends Bucke
       )
     }
 
+  private[this] def isAnonymousAWSParams(properties: StorageProperties): Boolean =
+    properties.getString(S3_ACCESS_KEY).isEmpty && properties.getString(S3_SECRET_KEY).isEmpty
+
   /**
    * @inheritdoc
    *
@@ -83,15 +86,22 @@ final case class S3Bucket(path: String, params: StorageProperties) extends Bucke
       properties
     }
 
-    conf.set("fs.s3a.access.key", mergedProperties.getString(S3_ACCESS_KEY))
-    conf.set("fs.s3a.secret.key", mergedProperties.getString(S3_SECRET_KEY))
-
-    if (mergedProperties.containsKey(S3_SESSION_TOKEN)) {
+    if (isAnonymousAWSParams(mergedProperties)) {
       conf.set(
         "fs.s3a.aws.credentials.provider",
-        classOf[org.apache.hadoop.fs.s3a.TemporaryAWSCredentialsProvider].getName()
+        classOf[org.apache.hadoop.fs.s3a.AnonymousAWSCredentialsProvider].getName()
       )
-      conf.set("fs.s3a.session.token", mergedProperties.getString(S3_SESSION_TOKEN))
+    } else {
+      conf.set("fs.s3a.access.key", mergedProperties.getString(S3_ACCESS_KEY))
+      conf.set("fs.s3a.secret.key", mergedProperties.getString(S3_SECRET_KEY))
+
+      if (mergedProperties.containsKey(S3_SESSION_TOKEN)) {
+        conf.set(
+          "fs.s3a.aws.credentials.provider",
+          classOf[org.apache.hadoop.fs.s3a.TemporaryAWSCredentialsProvider].getName()
+        )
+        conf.set("fs.s3a.session.token", mergedProperties.getString(S3_SESSION_TOKEN))
+      }
     }
 
     properties.getProxyHost().foreach { proxyHost =>

src/test/scala/com/exasol/cloudetl/bucket/S3BucketTest.scala

@@ -62,6 +62,15 @@ class S3BucketTest extends AbstractBucketTest {
     assertConfigurationProperties(bucket, configMappings - "fs.s3a.session.token")
   }
 
+  test(testName = "apply return specific credentials provider for public access configuration") {
+    val exaMetadata = mockConnectionInfo("access", "S3_ACCESS_KEY=;S3_SECRET_KEY=")
+    val bucket = getBucket(defaultProperties, exaMetadata)
+    assert(
+      bucket.getConfiguration().get("fs.s3a.aws.credentials.provider") ==
+        "org.apache.hadoop.fs.s3a.AnonymousAWSCredentialsProvider"
+    )
+  }
+
   test("apply returns S3Bucket with secret and session token from connection") {
     val exaMetadata = mockConnectionInfo("access", "S3_SECRET_KEY=secret;S3_SESSION_TOKEN=token")
     val bucket = getBucket(defaultProperties, exaMetadata)