Fix support for multiurl CCDB backends

Author: ktf

CCDB/src/CcdbApi.cxx

@@ -1363,8 +1363,15 @@ bool CcdbApi::isHostReachable() const
   curl = curl_easy_init();
   curl_easy_setopt(curl, CURLOPT_USERAGENT, mUniqueAgentID.c_str());
   if (curl) {
+    // Each host in turn, not mUrl: mUrl holds whatever was passed to init(),
+    // which for a failover setup is the whole comma-separated list. curl
+    // rejects that as malformed (CURLE_URL_MALFORMAT), so every multi-host
+    // instance reported itself unreachable no matter how healthy its hosts
+    // were -- and testCcdbApiMultipleUrls, whose cases are gated on this,
+    // silently skipped instead of running.
     for (size_t hostIndex = 0; hostIndex < hostsPool.size() && res != CURLE_OK; hostIndex++) {
-      curl_easy_setopt(curl, CURLOPT_URL, mUrl.data());
+      std::string url = getHostUrl(hostIndex);
+      curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
       curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
       curlSetSSLOptions(curl);
       res = CURL_perform(curl);

CCDB/test/testCcdbApiMultipleUrls.cxx

@@ -17,6 +17,7 @@
 #include "CCDB/CCDBTimeStampUtils.h"
 #include <boost/test/unit_test.hpp>
 #include <cstdio>
+#include <cstdlib>
 #include <TH1F.h>
 
 using namespace std;
@@ -35,7 +36,13 @@ struct Fixture {
   Fixture()
   {
     CcdbApi api;
-    ccdbUrl = "https://localhost:22,https://localhost:8080,http://ccdb-test.cern.ch:8080";
+    // This suite uploads, so it needs a WRITABLE instance -- ccdb-test by
+    // default, not the official CCDB. Only the LAST entry is configurable:
+    // what is under test here is the failover, so the two dead endpoints in
+    // front of it are part of the fixture and stay hardcoded.
+    const char* host = std::getenv("ALICEO2_CCDB_HOST");
+    ccdbUrl = "https://localhost:22,https://localhost:8080,";
+    ccdbUrl += host ? host : "http://ccdb-test.cern.ch:8080";
     api.init(ccdbUrl);
     cout << "ccdb url: " << ccdbUrl << endl;
     hostReachable = api.isHostReachable();