stats: rename statshostname to more appropriate statssuffix

kwvg · kwvg · commit 42918c2cdcb4 · 2024-10-04T08:48:23.000Z
`statshostname` implies that alongside specifying the host, the user
needs to specify a separate "hostname" field in order to connect when
in fact, it is an entirely optional suffix field applied to stats keys.

Rename it to `statssuffix` and deprecate `statshostname`, the latter
will be removed in a subsequent major release.
diff --git a/src/init.cpp b/src/init.cpp
@@ -775,10 +775,11 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-statsbatchsize=<bytes>", strprintf("Specify the size of each batch of stats messages (default: %d)", DEFAULT_STATSD_BATCH_SIZE), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
     argsman.AddArg("-statsduration=<ms>", strprintf("Specify the number of milliseconds between stats messages (default: %d)", DEFAULT_STATSD_DURATION), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
     argsman.AddArg("-statshost=<ip>", strprintf("Specify statsd host (default: %s)", DEFAULT_STATSD_HOST), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
-    argsman.AddArg("-statshostname=<ip>", strprintf("Specify statsd host name (default: %s)", DEFAULT_STATSD_HOSTNAME), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
+    hidden_args.emplace_back("-statshostname");
     argsman.AddArg("-statsport=<port>", strprintf("Specify statsd port (default: %u)", DEFAULT_STATSD_PORT), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
-    argsman.AddArg("-statsns=<ns>", strprintf("Specify additional namespace prefix (default: %s)", DEFAULT_STATSD_NAMESPACE), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
+    argsman.AddArg("-statsns=<ns>", strprintf("Specify additional namespace prefix (default: %s)", DEFAULT_STATSD_SUFFIX), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
     argsman.AddArg("-statsperiod=<seconds>", strprintf("Specify the number of seconds between periodic measurements (default: %d)", DEFAULT_STATSD_PERIOD), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
+    argsman.AddArg("-statssuffix=<string>", strprintf("Specify an optional string appended to every stats key (default: %s)", DEFAULT_STATSD_SUFFIX), ArgsManager::ALLOW_ANY, OptionsCategory::STATSD);
 #if HAVE_DECL_FORK
     argsman.AddArg("-daemon", strprintf("Run in the background as a daemon and accept commands (default: %d)", DEFAULT_DAEMON), ArgsManager::ALLOW_BOOL, OptionsCategory::OPTIONS);
     argsman.AddArg("-daemonwait", strprintf("Wait for initialization to be finished before exiting. This implies -daemon (default: %d)", DEFAULT_DAEMONWAIT), ArgsManager::ALLOW_BOOL, OptionsCategory::OPTIONS);
diff --git a/src/stats/client.cpp b/src/stats/client.cpp
@@ -49,6 +49,8 @@ static constexpr float EPSILON{0.0001f};
 
 /** Delimiter segmenting two fully formed Statsd messages */
 static constexpr char STATSD_MSG_DELIMITER{'\n'};
+/** Delimiter segmenting namespaces in a Statsd key */
+static constexpr char STATSD_NS_DELIMITER{'.'};
 /** Character used to denote Statsd message type as count */
 static constexpr char STATSD_METRIC_COUNT[]{"c"};
 /** Character used to denote Statsd message type as gauge */
@@ -76,21 +78,41 @@ std::unique_ptr<StatsdClient> InitStatsClient(const ArgsManager& args)
         is_enabled = true;
     }
 
+    auto sanitize_string = [](std::string& string) {
+        // Remove key delimiters from the front and back as they're added back
+        // in formatting
+        if (!string.empty()) {
+            if (string.front() == STATSD_NS_DELIMITER) string.erase(string.begin());
+            if (string.back() == STATSD_NS_DELIMITER) string.pop_back();
+        }
+    };
+
+    // Get our suffix and if we get nothing, try again with the deprecated
+    // argument. If we still get nothing, that's fine, suffixes are optional.
+    auto suffix = args.GetArg("-statssuffix", DEFAULT_STATSD_SUFFIX);
+    if (suffix.empty()) {
+        suffix = args.GetArg("-statshostname", DEFAULT_STATSD_SUFFIX);
+    } else {
+        // We restrict sanitization logic to our newly added arguments to
+        // prevent breaking changes.
+        sanitize_string(suffix);
+    }
+
     return std::make_unique<StatsdClient>(
         host,
         args.GetArg("-statsport", DEFAULT_STATSD_PORT),
         args.GetArg("-statsbatchsize", DEFAULT_STATSD_BATCH_SIZE),
         args.GetArg("-statsduration", DEFAULT_STATSD_DURATION),
-        args.GetArg("-statshostname", DEFAULT_STATSD_HOSTNAME),
         args.GetArg("-statsns", DEFAULT_STATSD_NAMESPACE),
+        suffix,
         is_enabled
     );
 }
 
 StatsdClient::StatsdClient(const std::string& host, uint16_t port, uint64_t batch_size, uint64_t interval_ms,
-                           const std::string& nodename, const std::string& ns, bool enabled) :
-    m_nodename{nodename},
-    m_ns{ns}
+                           const std::string& ns, const std::string& suffix, bool enabled) :
+    m_ns{ns},
+    m_suffix{[suffix]() { return !suffix.empty() ? STATSD_NS_DELIMITER + suffix : suffix; }()}
 {
     if (!enabled) {
         LogPrintf("Transmitting stats are disabled, will not init StatsdClient\n");
@@ -154,11 +176,8 @@ bool StatsdClient::send(const std::string& key, T1 value, const std::string& typ
         return true;
     }
 
-    // partition stats by node name if set
-    if (!m_nodename.empty()) key = key + "." + m_nodename;
-
     // Construct the message and if our message isn't always-send, report the sample rate
-    RawMessage msg{strprintf("%s%s:%f|%s", m_ns, key, value, type)};
+    RawMessage msg{strprintf("%s%s%s:%f|%s", m_ns, key, m_suffix, value, type)};
     if (!always_send) {
         msg += strprintf("|@%.2f", sample_rate);
     }
diff --git a/src/stats/client.h b/src/stats/client.h
@@ -20,10 +20,10 @@ class RawSender;
 static constexpr uint16_t DEFAULT_STATSD_PORT{8125};
 /** Default host assumed to be running a Statsd server */
 static const std::string DEFAULT_STATSD_HOST{"127.0.0.1"};
-/** Default suffix appended to Statsd message keys */
-static const std::string DEFAULT_STATSD_HOSTNAME{""};
 /** Default prefix prepended to Statsd message keys */
 static const std::string DEFAULT_STATSD_NAMESPACE{""};
+/** Default suffix appended to Statsd message keys */
+static const std::string DEFAULT_STATSD_SUFFIX{""};
 
 /** Default number of milliseconds between flushing a queue of messages */
 static constexpr int DEFAULT_STATSD_DURATION{1000};
@@ -40,7 +40,7 @@ class StatsdClient
 {
 public:
     explicit StatsdClient(const std::string& host, uint16_t port, uint64_t batch_size, uint64_t interval_ms,
-                          const std::string& nodename, const std::string& ns, bool enabled);
+                          const std::string& ns, const std::string& suffix, bool enabled);
     ~StatsdClient();
 
 public:
@@ -69,9 +69,9 @@ class StatsdClient
     std::unique_ptr<RawSender> m_sender{nullptr};
 
     /* Phrase prepended to keys */
-    const std::string m_nodename;
-    /* Phrase appended to keys */
     const std::string m_ns;
+    /* Phrase appended to keys */
+    const std::string m_suffix{""};
 };
 
 /** Parses arguments and constructs a StatsdClient instance */
