sunchao commented on a change in pull request #2110:
URL: https://github.com/apache/hadoop/pull/2110#discussion_r448022518
##########
File path:
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java
##########
@@ -726,4 +732,41 @@ public TokenIdent decodeTokenIdentifier(Token<TokenIdent>
token) throws IOExcept
return token.decodeIdentifier();
}
+ /**
+ * Return top token real owners list as well as the tokens count.
+ *
+ * @param n top number of users
+ * @return map of owners to counts
+ */
+ public List<NameValuePair> getTopTokenRealOwners(int n) {
+ Map<String, Integer> tokenOwnerMap = new HashMap<>();
+ for (TokenIdent id : currentTokens.keySet()) {
+ String realUser;
+ if (id.getRealUser() != null && !id.getRealUser().toString().isEmpty()) {
+ realUser = id.getRealUser().toString();
+ } else {
+ // if there is no real user -> this is a non proxy user
+ // the user itself is the real owner
+ realUser = id.getUser().getUserName();
+ }
+ tokenOwnerMap.put(realUser, tokenOwnerMap.getOrDefault(realUser, 0)+1);
+ }
+ n = Math.min(n, tokenOwnerMap.size());
+ if (n == 0) {
+ return new LinkedList<>();
+ }
+
+ TopN topN = new TopN(n);
+ for (Map.Entry<String, Integer> entry : tokenOwnerMap.entrySet()) {
+ topN.offer(new NameValuePair(
+ entry.getKey(), entry.getValue()));
+ }
+
+ List<NameValuePair> list = new LinkedList<>();
Review comment:
Reverse shouldn't need extra space - it uses two indexes from begin and
end of the array and swaps elements. I don't see real difference between the
two for the reverse.
##########
File path:
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenSecretManager.java
##########
@@ -726,4 +732,41 @@ public TokenIdent decodeTokenIdentifier(Token<TokenIdent>
token) throws IOExcept
return token.decodeIdentifier();
}
+ /**
+ * Return top token real owners list as well as the tokens count.
+ *
+ * @param n top number of users
+ * @return map of owners to counts
+ */
+ public List<NameValuePair> getTopTokenRealOwners(int n) {
Review comment:
Can we update the `TopN` queue when creating/deleting tokens? we are
just paying an extra constant cost for updating that which I think is fine.
Even though it is using concurrent hashmap, I'm not sure how much performance
impact will be if one thread is iterating over the key set while others want to
updating the map.
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