be/src/util/dns_cache.cpp
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1 | | // Licensed to the Apache Software Foundation (ASF) under one |
2 | | // or more contributor license agreements. See the NOTICE file |
3 | | // distributed with this work for additional information |
4 | | // regarding copyright ownership. The ASF licenses this file |
5 | | // to you under the Apache License, Version 2.0 (the |
6 | | // "License"); you may not use this file except in compliance |
7 | | // with the License. You may obtain a copy of the License at |
8 | | // |
9 | | // http://www.apache.org/licenses/LICENSE-2.0 |
10 | | // |
11 | | // Unless required by applicable law or agreed to in writing, |
12 | | // software distributed under the License is distributed on an |
13 | | // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
14 | | // KIND, either express or implied. See the License for the |
15 | | // specific language governing permissions and limitations |
16 | | // under the License. |
17 | | |
18 | | #include "util/dns_cache.h" |
19 | | |
20 | | #include "service/backend_options.h" |
21 | | #include "util/network_util.h" |
22 | | |
23 | | namespace doris { |
24 | | |
25 | 7 | DNSCache::DNSCache() { |
26 | 7 | refresh_thread = std::thread(&DNSCache::_refresh_cache, this); |
27 | 7 | } |
28 | | |
29 | 3 | DNSCache::~DNSCache() { |
30 | 3 | stop_refresh = true; |
31 | 3 | if (refresh_thread.joinable()) { |
32 | 3 | refresh_thread.join(); |
33 | 3 | } |
34 | 3 | } |
35 | | |
36 | 106k | Status DNSCache::get(const std::string& hostname, std::string* ip) { |
37 | 106k | { |
38 | 106k | std::shared_lock<std::shared_mutex> lock(mutex); |
39 | 106k | auto it = cache.find(hostname); |
40 | 106k | if (it != cache.end()) { |
41 | 106k | *ip = it->second; |
42 | 106k | return Status::OK(); |
43 | 106k | } |
44 | 106k | } |
45 | | // Update if not found |
46 | 18.4E | RETURN_IF_ERROR(_update(hostname)); |
47 | 18.4E | { |
48 | 18.4E | std::shared_lock<std::shared_mutex> lock(mutex); |
49 | 18.4E | *ip = cache[hostname]; |
50 | 18.4E | return Status::OK(); |
51 | 18.4E | } |
52 | 18.4E | } |
53 | | |
54 | | // Resolve hostname to IP address, similar to Java's DNSCache.resolveHostname. |
55 | | // If resolution fails, falls back to cached IP if available. |
56 | | // Returns the resolved IP, or cached IP on failure, or empty string if no cache available. |
57 | 99 | std::string DNSCache::_resolve_hostname(const std::string& hostname) { |
58 | | // Get cached IP first (if any) |
59 | 99 | std::string cached_ip; |
60 | 99 | { |
61 | 99 | std::shared_lock<std::shared_mutex> lock(mutex); |
62 | 99 | auto it = cache.find(hostname); |
63 | 99 | if (it != cache.end()) { |
64 | 92 | cached_ip = it->second; |
65 | 92 | } |
66 | 99 | } |
67 | | |
68 | | // Try to resolve hostname |
69 | 99 | std::string resolved_ip; |
70 | 99 | Status status = hostname_to_ip(hostname, resolved_ip, BackendOptions::is_bind_ipv6()); |
71 | | |
72 | 99 | if (!status.ok() || resolved_ip.empty()) { |
73 | | // Resolution failed |
74 | 0 | if (!cached_ip.empty()) { |
75 | 0 | LOG(WARNING) << "Failed to resolve hostname " << hostname |
76 | 0 | << ", use cached ip: " << cached_ip; |
77 | 0 | return cached_ip; |
78 | 0 | } else { |
79 | 0 | LOG(WARNING) << "Failed to resolve hostname " << hostname << ", no cached ip available"; |
80 | 0 | return ""; |
81 | 0 | } |
82 | 0 | } |
83 | | |
84 | 99 | return resolved_ip; |
85 | 99 | } |
86 | | |
87 | 99 | Status DNSCache::_update(const std::string& hostname) { |
88 | 99 | std::string real_ip = _resolve_hostname(hostname); |
89 | 99 | if (real_ip.empty()) { |
90 | 0 | return Status::InternalError("Failed to resolve hostname {} and no cached ip available", |
91 | 0 | hostname); |
92 | 0 | } |
93 | | |
94 | 99 | std::unique_lock<std::shared_mutex> lock(mutex); |
95 | 99 | auto it = cache.find(hostname); |
96 | 99 | if (it == cache.end() || it->second != real_ip) { |
97 | 7 | cache[hostname] = real_ip; |
98 | 7 | LOG(INFO) << "update hostname " << hostname << "'s ip to " << real_ip; |
99 | 7 | } |
100 | 99 | return Status::OK(); |
101 | 99 | } |
102 | | |
103 | 7 | void DNSCache::_refresh_cache() { |
104 | 105 | while (!stop_refresh) { |
105 | | // refresh every 1 min |
106 | 98 | std::this_thread::sleep_for(std::chrono::minutes(1)); |
107 | 98 | std::unordered_set<std::string> keys; |
108 | 98 | { |
109 | 98 | std::shared_lock<std::shared_mutex> lock(mutex); |
110 | 98 | std::transform(cache.begin(), cache.end(), std::inserter(keys, keys.end()), |
111 | 98 | [](const auto& pair) { return pair.first; }); |
112 | 98 | } |
113 | 98 | for (auto& key : keys) { |
114 | 92 | Status st = _update(key); |
115 | 92 | if (!st.ok()) { |
116 | | LOG(WARNING) << "Failed to update DNS cache for hostname " << key << ": " |
117 | 0 | << st.to_string(); |
118 | 0 | } |
119 | 92 | } |
120 | 98 | } |
121 | 7 | } |
122 | | |
123 | | } // end of namespace doris |