Fix newline terminator for bulk requests in ElasticsearchWriter

This enables compatibility with 6.x.

This commit also fixes an incorrect HTTP response parsing
which could lead into false positives.

Analysis and fix in https://github.com/Icinga/icinga2/issues/5795#issuecomment-349920587

fixes #5795

refs #5840

diff --git a/lib/perfdata/elasticsearchwriter.cpp b/lib/perfdata/elasticsearchwriter.cpp
index 69221fd88ff8b943517b6a4cc519573448015586..2171752cacde19be617715e08bda92d035722bdd 100644 (file)
--- a/lib/perfdata/elasticsearchwriter.cpp
+++ b/lib/perfdata/elasticsearchwriter.cpp
@@ -395,6 +395,11 @@ void ElasticsearchWriter::Flush(void)
        String body = boost::algorithm::join(m_DataBuffer, "\n");
        m_DataBuffer.clear();
 
+       /* Elasticsearch 6.x requires a new line. This is compatible to 5.x.
+        * Tested with 6.0.0 and 5.6.4.
+        */
+       body += "\n";
+
        SendRequest(body);
 }
 
@@ -454,12 +459,20 @@ void ElasticsearchWriter::SendRequest(const String& body)
 
        try {
                resp.Parse(context, true);
+               while (resp.Parse(context, true) && !resp.Complete)
+                       ; /* Do nothing */
        } catch (const std::exception& ex) {
                Log(LogWarning, "ElasticsearchWriter")
-                       << "Cannot read from HTTP API on host '" << GetHost() << "' port '" << GetPort() << "'.";
+                   << "Failed to parse HTTP response from host '" << GetHost() << "' port '" << GetPort() << "': " << DiagnosticInformation(ex, false);
                throw ex;
        }
 
+       if (!resp.Complete) {
+               Log(LogWarning, "ElasticsearchWriter")
+                   << "Failed to read a complete HTTP response from the Elasticsearch server.";
+               return;
+       }
+
        if (resp.StatusCode > 299) {
                if (resp.StatusCode == 401) {
                        /* More verbose error logging with Elasticsearch is hidden behind a proxy. */
@@ -478,10 +491,6 @@ void ElasticsearchWriter::SendRequest(const String& body)
                Log(LogWarning, "ElasticsearchWriter")
                    << "Unexpected response code " << resp.StatusCode;
 
-               /* Finish parsing the headers and body. */
-               while (!resp.Complete)
-                       resp.Parse(context, true);
-
                String contentType = resp.Headers->Get("content-type");
 
                if (contentType != "application/json") {
@@ -508,6 +517,8 @@ void ElasticsearchWriter::SendRequest(const String& body)
 
                Log(LogCritical, "ElasticsearchWriter")
                    << "Elasticsearch error message:\n" << error;
+
+               return;
        }
 }