Introduce HeaderMaskingFunction

- A header name is necessary to dynamically mask header values. - Handle a null value returned by masking functions. - Replace Function<String,String` with `HeaderMaskingFunction`. - `HeaderSanitizer` their builders are moved to `common.logging` from `common`.
line · Jan 29, 2024 · b7697b5 · b7697b5
1 parent 042141a
commit b7697b5
Show file tree

Hide file tree

Showing 14 changed files with 185 additions and 56 deletions.
diff --git a/...mmon/AbstractHeadersSanitizerBuilder.java → ...ging/AbstractHeadersSanitizerBuilder.java b/...mmon/AbstractHeadersSanitizerBuilder.java → ...ging/AbstractHeadersSanitizerBuilder.java
@@ -14,7 +14,7 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
+package com.linecorp.armeria.common.logging;
 
 import static java.util.Objects.requireNonNull;
 
@@ -24,6 +24,8 @@
 
 import com.google.common.collect.ImmutableSet;
 
+import com.linecorp.armeria.common.HttpHeaderNames;
+
 import io.netty.util.AsciiString;
 
 /**
@@ -41,7 +43,9 @@ public abstract class AbstractHeadersSanitizerBuilder<T> {
 
     private final Set<AsciiString> maskingHeaders = new HashSet<>();
 
-    private Function<String, String> maskingFunction = header -> "****";
+    private HeaderMaskingFunction maskingFunction = HeaderMaskingFunction.of();
+
+    AbstractHeadersSanitizerBuilder() {}
 
     /**
      * Sets the headers to mask before logging.
@@ -69,16 +73,29 @@ final Set<AsciiString> maskingHeaders() {
 
     /**
      * Sets the {@link Function} to use to maskFunction headers before logging.
+     * The default maskingFunction is {@link HeaderMaskingFunction#of()}
+     *
+     * <pre>{@code
+     * builder.maskingFunction((name, value) -> {
+     *   if (name.equals(HttpHeaderNames.AUTHORIZATION)) {
+     *      return "****";
+     *   } else if (name.equals(HttpHeaderNames.COOKIE)) {
+     *     return name.substring(0, 4) + "****";
+     *   } else {
+     *     return value;
+     *   }
+     * }
+     * }</pre>
      */
-    public AbstractHeadersSanitizerBuilder<T> maskingFunction(Function<String, String> maskingFunction) {
+    public AbstractHeadersSanitizerBuilder<T> maskingFunction(HeaderMaskingFunction maskingFunction) {
         this.maskingFunction = requireNonNull(maskingFunction, "maskingFunction");
         return this;
     }
 
     /**
      * Returns the {@link Function} to use to mask headers before logging.
      */
-    final Function<String, String> maskingFunction() {
+    final HeaderMaskingFunction maskingFunction() {
         return maskingFunction;
     }
 }
diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/AbstractLogFormatterBuilder.java b/core/src/main/java/com/linecorp/armeria/common/logging/AbstractLogFormatterBuilder.java
@@ -21,7 +21,6 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-import com.linecorp.armeria.common.HeadersSanitizer;
 import com.linecorp.armeria.common.HttpHeaders;
 import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.annotation.Nullable;

diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/HeaderMaskingFunction.java b/core/src/main/java/com/linecorp/armeria/common/logging/HeaderMaskingFunction.java
@@ -0,0 +1,42 @@
+/*
+ *  Copyright 2024 LINE Corporation
+ *
+ *  LINE Corporation licenses this file to you under the Apache License,
+ *  version 2.0 (the "License"); you may not use this file except in compliance
+ *  with the License. You may obtain a copy of the License at:
+ *
+ *    https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *  License for the specific language governing permissions and limitations
+ *  under the License.
+ */
+
+package com.linecorp.armeria.common.logging;
+
+import com.linecorp.armeria.common.annotation.Nullable;
+
+import io.netty.util.AsciiString;
+
+/**
+ * A function that masks the specified header value.
+ */
+@FunctionalInterface
+public interface HeaderMaskingFunction {
+
+    /**
+     * Returns the default {@link HeaderMaskingFunction} that masks the given value with {@code ****}.
+     */
+    static HeaderMaskingFunction of() {
+        return (name, value) -> "****";
+    }
+
+    /**
+     * Masks the specified {@code value} of the specified {@code name}.
+     * If {@code null} is returned, the specified {@code value} will be removed from the log.
+     */
+    @Nullable
+    String mask(AsciiString name, String value);
+}
diff --git a/...corp/armeria/common/HeadersSanitizer.java → ...eria/common/logging/HeadersSanitizer.java b/...corp/armeria/common/HeadersSanitizer.java → ...eria/common/logging/HeadersSanitizer.java
@@ -14,12 +14,15 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
+package com.linecorp.armeria.common.logging;
 
 import java.util.function.BiFunction;
 
 import com.fasterxml.jackson.databind.JsonNode;
 
+import com.linecorp.armeria.common.HttpHeaderNames;
+import com.linecorp.armeria.common.HttpHeaders;
+import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.annotation.Nullable;
 
 /**
@@ -28,9 +31,9 @@
 @FunctionalInterface
 public interface HeadersSanitizer<T> extends BiFunction<RequestContext, HttpHeaders, T> {
     /**
-     * Returns the default text {@link HeadersSanitizer}.
-     * {@link HttpHeaderNames#AUTHORIZATION}, {@link HttpHeaderNames#COOKIE}, {@link HttpHeaderNames#SET_COOKIE},
-     * and {@link HttpHeaderNames#PROXY_AUTHORIZATION} are masked.
+     * Returns the default text {@link HeadersSanitizer} that masks
+     * {@link HttpHeaderNames#AUTHORIZATION}, {@link HttpHeaderNames#COOKIE},
+     * {@link HttpHeaderNames#SET_COOKIE}, and {@link HttpHeaderNames#PROXY_AUTHORIZATION} with {@code ****}.
      */
     static HeadersSanitizer<String> ofText() {
         return TextHeadersSanitizer.INSTANCE;
@@ -44,9 +47,9 @@ static TextHeadersSanitizerBuilder builderForText() {
     }
 
     /**
-     * Returns the default json {@link HeadersSanitizer}.
-     * {@link HttpHeaderNames#AUTHORIZATION}, {@link HttpHeaderNames#COOKIE}, {@link HttpHeaderNames#SET_COOKIE},
-     * and {@link HttpHeaderNames#PROXY_AUTHORIZATION} are masked.
+     * Returns the default JSON {@link HeadersSanitizer} that masks
+     * {@link HttpHeaderNames#AUTHORIZATION}, {@link HttpHeaderNames#COOKIE},
+     * {@link HttpHeaderNames#SET_COOKIE}, and {@link HttpHeaderNames#PROXY_AUTHORIZATION} with {@code ****}.
      */
     static HeadersSanitizer<JsonNode> ofJson() {
         return JsonHeadersSanitizer.INSTANCE;

diff --git a/.../armeria/common/JsonHeadersSanitizer.java → .../common/logging/JsonHeadersSanitizer.java b/.../armeria/common/JsonHeadersSanitizer.java → .../common/logging/JsonHeadersSanitizer.java
@@ -14,17 +14,19 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
+package com.linecorp.armeria.common.logging;
 
-import static com.linecorp.armeria.common.TextHeadersSanitizer.maskHeaders;
+import static com.linecorp.armeria.common.logging.TextHeadersSanitizer.maskHeaders;
 
 import java.util.Set;
-import java.util.function.Function;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
+import com.linecorp.armeria.common.HttpHeaders;
+import com.linecorp.armeria.common.RequestContext;
+
 import io.netty.util.AsciiString;
 
 /**
@@ -34,10 +36,10 @@ final class JsonHeadersSanitizer implements HeadersSanitizer<JsonNode> {
 
     static final HeadersSanitizer<JsonNode> INSTANCE = new JsonHeadersSanitizerBuilder().build();
     private final Set<AsciiString> maskingHeaders;
-    private final Function<String, String> maskingFunction;
+    private final HeaderMaskingFunction maskingFunction;
     private final ObjectMapper objectMapper;
 
-    JsonHeadersSanitizer(Set<AsciiString> maskingHeaders, Function<String, String> maskingFunction,
+    JsonHeadersSanitizer(Set<AsciiString> maskingHeaders, HeaderMaskingFunction maskingFunction,
                          ObjectMapper objectMapper) {
         this.maskingHeaders = maskingHeaders;
         this.maskingFunction = maskingFunction;

diff --git a/...a/common/JsonHeadersSanitizerBuilder.java → .../logging/JsonHeadersSanitizerBuilder.java b/...a/common/JsonHeadersSanitizerBuilder.java → .../logging/JsonHeadersSanitizerBuilder.java
@@ -14,12 +14,10 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
+package com.linecorp.armeria.common.logging;
 
 import static java.util.Objects.requireNonNull;
 
-import java.util.function.Function;
-
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
@@ -45,7 +43,7 @@ public JsonHeadersSanitizerBuilder maskingHeaders(Iterable<? extends CharSequenc
     }
 
     @Override
-    public JsonHeadersSanitizerBuilder maskingFunction(Function<String, String> maskingFunction) {
+    public JsonHeadersSanitizerBuilder maskingFunction(HeaderMaskingFunction maskingFunction) {
         return (JsonHeadersSanitizerBuilder) super.maskingFunction(maskingFunction);
     }
 

diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/JsonLogFormatter.java b/core/src/main/java/com/linecorp/armeria/common/logging/JsonLogFormatter.java
@@ -29,7 +29,6 @@
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.google.common.base.MoreObjects;
 
-import com.linecorp.armeria.common.HeadersSanitizer;
 import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.SerializationFormat;
 import com.linecorp.armeria.common.annotation.Nullable;

diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/JsonLogFormatterBuilder.java b/core/src/main/java/com/linecorp/armeria/common/logging/JsonLogFormatterBuilder.java
@@ -24,7 +24,6 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
-import com.linecorp.armeria.common.HeadersSanitizer;
 import com.linecorp.armeria.common.HttpHeaders;
 import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.annotation.Nullable;

diff --git a/.../armeria/common/TextHeadersSanitizer.java → .../common/logging/TextHeadersSanitizer.java b/.../armeria/common/TextHeadersSanitizer.java → .../common/logging/TextHeadersSanitizer.java
@@ -14,17 +14,20 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
+package com.linecorp.armeria.common.logging;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 import java.util.function.BiConsumer;
-import java.util.function.Function;
 
 import com.google.common.collect.ImmutableList;
 
+import com.linecorp.armeria.common.HttpHeaders;
+import com.linecorp.armeria.common.RequestContext;
+
 import io.netty.util.AsciiString;
 
 /**
@@ -36,9 +39,10 @@ final class TextHeadersSanitizer implements HeadersSanitizer<String> {
 
     private final Set<AsciiString> maskingHeaders;
 
-    private final Function<String, String> maskingFunction;
+    private final HeaderMaskingFunction maskingFunction;
 
-    TextHeadersSanitizer(Set<AsciiString> maskingHeaders, Function<String, String> maskingFunction) {
+    TextHeadersSanitizer(Set<AsciiString> maskingHeaders,
+                         HeaderMaskingFunction maskingFunction) {
         this.maskingHeaders = maskingHeaders;
         this.maskingFunction = maskingFunction;
     }
@@ -66,19 +70,30 @@ public String sanitize(RequestContext ctx, HttpHeaders headers) {
     }
 
     static void maskHeaders(
-            HttpHeaders headers, Set<AsciiString> maskingHeaders, Function<String, String> maskingFunction,
-            final BiConsumer<AsciiString, List<String>> consumer) {
+            HttpHeaders headers, Set<AsciiString> maskingHeaders,
+            HeaderMaskingFunction maskingFunction,
+            BiConsumer<AsciiString, List<String>> consumer) {
         for (AsciiString headerName : headers.names()) {
             List<String> values = headers.getAll(headerName);
             if (maskingHeaders.contains(headerName)) {
                 // Mask the header values.
                 if (values.size() == 1) {
-                    values = ImmutableList.of(maskingFunction.apply(values.get(0)));
+                    final String masked = maskingFunction.mask(headerName, values.get(0));
+                    if (masked == null) {
+                        values = ImmutableList.of();
+                    } else {
+                        values = ImmutableList.of(masked);
+                    }
                 } else {
-                    values = values.stream().map(maskingFunction).collect(toImmutableList());
+                    values = values.stream()
+                                   .map(value -> maskingFunction.mask(headerName, value))
+                                   .filter(Objects::nonNull)
+                                   .collect(toImmutableList());
                 }
             }
-            consumer.accept(headerName, values);
+            if (!values.isEmpty()) {
+                consumer.accept(headerName, values);
+            }
         }
     }
 }
diff --git a/...a/common/TextHeadersSanitizerBuilder.java → .../logging/TextHeadersSanitizerBuilder.java b/...a/common/TextHeadersSanitizerBuilder.java → .../logging/TextHeadersSanitizerBuilder.java
@@ -14,9 +14,7 @@
  * under the License.
  */
 
-package com.linecorp.armeria.common;
-
-import java.util.function.Function;
+package com.linecorp.armeria.common.logging;
 
 /**
  * A builder implementation for Text {@link HeadersSanitizer}.
@@ -34,7 +32,7 @@ public TextHeadersSanitizerBuilder maskingHeaders(Iterable<? extends CharSequenc
     }
 
     @Override
-    public TextHeadersSanitizerBuilder maskingFunction(Function<String, String> maskingFunction) {
+    public TextHeadersSanitizerBuilder maskingFunction(HeaderMaskingFunction maskingFunction) {
         return (TextHeadersSanitizerBuilder) super.maskingFunction(maskingFunction);
     }
 

diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/TextLogFormatter.java b/core/src/main/java/com/linecorp/armeria/common/logging/TextLogFormatter.java
@@ -23,7 +23,6 @@
 
 import com.google.common.base.MoreObjects;
 
-import com.linecorp.armeria.common.HeadersSanitizer;
 import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.SerializationFormat;
 import com.linecorp.armeria.common.annotation.Nullable;

diff --git a/core/src/main/java/com/linecorp/armeria/common/logging/TextLogFormatterBuilder.java b/core/src/main/java/com/linecorp/armeria/common/logging/TextLogFormatterBuilder.java
@@ -20,7 +20,6 @@
 
 import java.util.function.BiFunction;
 
-import com.linecorp.armeria.common.HeadersSanitizer;
 import com.linecorp.armeria.common.HttpHeaders;
 import com.linecorp.armeria.common.RequestContext;
 import com.linecorp.armeria.common.annotation.Nullable;