Redfish: Support Host Log Entries

This commit is designing and implementing a new logging service in
Redfish to expose host serial console logs.The goal is that clients
can talk to bmc via Redfish and get a real-time console. It will improve
the debuggability of BMCs.

We will add three paths to redfish tree to implement the feature:
1. /redfish/v1/Systems/system/LogServices/HostLogger
2. /redfish/v1/Systems/system/LogServices/HostLogger/Entries
3. /redfish/v1/Systems/system/LogServices/HostLogger/Entries/<str>

To use this feature, we expect to use phosphor-hostlogger(stream mode)
+ rsyslog + bmcweb. Phosphor-hostlooger in stream mode forwards the byte
stream into rsyslog via the imuxsock module. The log is persisted via
the omfile module as soon as collected. It makes Host Logger leverage
exsisting tools (rsyslog and logrotate). Then we can expose host serial
console logs via bmcweb.

This feature can be enabled or disabled by setting the option
"redfish-host-logger", and the default value is "enabled". If you don't
want to expose host serial console logs, you need to turn the value to
"disabled".

RedfishServiceValidator results:
/redfish/v1/Systems/system/LogServices/HostLogger
pass: 4
passGet: 1
skipOptional: 9

/redfish/v1/Systems/system/LogServices/HostLogger/Entries
pass: 24
passGet: 1
skipOptional: 1

/redfish/v1/Systems/system/LogServices/HostLogger/Entries/<str>
pass: 7
passGet: 1
skipOptional: 15

Sample Output:
curl -k -H "X-Auth-Token: $token" -X GET https://${bmc}/redfish/v1/Systems/system/LogServices/HostLogger/Entries
{
  "@odata.id": "/redfish/v1/Systems/system/LogServices/HostLogger/Entries",
  "@odata.type": "#LogEntryCollection.LogEntryCollection",
  "Description": "Collection of HostLogger Entries",
  "Members": [
    {
      "@odata.id": "/redfish/v1/Systems/system/LogServices/HostLogger/Entries/1",
      "@odata.type": "#LogEntry.v1_4_0.LogEntry",
      "EntryType": "Event",
      "Id": "1",
      "Message": "[   57.061546] gq 0000:16:00.0 eth0: link up, 100 Gbps, no PAUSE",
      "MessageArgs": [
        "[   57.061546] gq 0000:16:00.0 eth0: link up, 100 Gbps, no PAUSE"
      ],
      "MessageId": "OpenBMC.0.1.SerialLogAdded",
      "Name": "HostLogger Entries",
      "Severity": "OK"
    },
  ...
  ],
  "Members@odata.count": 22,
  "Name": "HostLogger Entries"
}

Signed-off-by: SpencerKu <Spencer.Ku@quantatw.com>
Change-Id: I5a7873caa117400fb0a737588a50bd743e8b5063
diff --git a/redfish-core/lib/log_services.hpp b/redfish-core/lib/log_services.hpp
index 2c9ae3a..065a4d1 100644
--- a/redfish-core/lib/log_services.hpp
+++ b/redfish-core/lib/log_services.hpp
@@ -15,7 +15,9 @@
 */
 #pragma once
 
+#include "gzfile.hpp"
 #include "http_utility.hpp"
+#include "human_sort.hpp"
 #include "registries.hpp"
 #include "registries/base_message_registry.hpp"
 #include "registries/openbmc_message_registry.hpp"
@@ -975,6 +977,12 @@
                     {{"@odata.id",
                       "/redfish/v1/Systems/system/LogServices/Crashdump"}});
 #endif
+
+#ifdef BMCWEB_ENABLE_REDFISH_HOST_LOGGER
+                logServiceArray.push_back(
+                    {{"@odata.id",
+                      "/redfish/v1/Systems/system/LogServices/HostLogger"}});
+#endif
                 asyncResp->res.jsonValue["Members@odata.count"] =
                     logServiceArray.size();
 
@@ -1817,6 +1825,221 @@
             });
 }
 
+constexpr const char* hostLoggerFolderPath = "/var/log/console";
+inline bool
+    getHostLoggerFiles(const std::string& hostLoggerFilePath,
+                       std::vector<std::filesystem::path>& hostLoggerFiles)
+{
+    std::error_code ec;
+    std::filesystem::directory_iterator logPath(hostLoggerFilePath, ec);
+    if (ec)
+    {
+        BMCWEB_LOG_ERROR << ec.message();
+        return false;
+    }
+    for (const std::filesystem::directory_entry& it : logPath)
+    {
+        std::string filename = it.path().filename();
+        // Prefix of each log files is "log". Find the file and save the
+        // path
+        if (boost::starts_with(filename, "log"))
+        {
+            hostLoggerFiles.emplace_back(it.path());
+        }
+    }
+    // As the log files rotate, they are appended with a ".#" that is higher for
+    // the older logs. Since we start from oldest logs, sort the name in
+    // descending order.
+    std::sort(hostLoggerFiles.rbegin(), hostLoggerFiles.rend(),
+              AlphanumLess<std::string>());
+
+    return true;
+}
+
+inline bool
+    getHostLoggerEntries(std::vector<std::filesystem::path>& hostLoggerFiles,
+                         std::vector<std::string>& logEntries)
+{
+    GzFileReader logFile;
+
+    // Go though all log files and expose host log into logEntries
+    for (const std::filesystem::path& it : hostLoggerFiles)
+    {
+        if (!logFile.gzGetLines(logEntries, it.string()))
+        {
+            BMCWEB_LOG_ERROR << "fail to expose host logs";
+            return false;
+        }
+    }
+    // Get lastMessage from constructor by getter
+    std::string lastMessage = logFile.getLastMessage();
+    if (!lastMessage.empty())
+    {
+        logEntries.push_back(lastMessage);
+    }
+    return true;
+}
+
+inline void fillHostLoggerEntryJson(const std::string& logEntryID,
+                                    const std::string& msg,
+                                    nlohmann::json& logEntryJson)
+{
+    // Fill in the log entry with the gathered data.
+    logEntryJson = {
+        {"@odata.type", "#LogEntry.v1_4_0.LogEntry"},
+        {"@odata.id",
+         "/redfish/v1/Systems/system/LogServices/HostLogger/Entries/" +
+             logEntryID},
+        {"Name", "Host Logger Entry"},
+        {"Id", logEntryID},
+        {"Message", msg},
+        {"EntryType", "Oem"},
+        {"Severity", "OK"},
+        {"OemRecordFormat", "Host Logger Entry"}};
+}
+
+inline void requestRoutesSystemHostLogger(App& app)
+{
+    BMCWEB_ROUTE(app, "/redfish/v1/Systems/system/LogServices/HostLogger/")
+        .privileges(redfish::privileges::getLogService)
+        .methods(boost::beast::http::verb::get)(
+            [](const crow::Request&,
+               const std::shared_ptr<bmcweb::AsyncResp>& asyncResp) {
+                asyncResp->res.jsonValue["@odata.id"] =
+                    "/redfish/v1/Systems/system/LogServices/HostLogger";
+                asyncResp->res.jsonValue["@odata.type"] =
+                    "#LogService.v1_1_0.LogService";
+                asyncResp->res.jsonValue["Name"] = "Host Logger Service";
+                asyncResp->res.jsonValue["Description"] = "Host Logger Service";
+                asyncResp->res.jsonValue["Id"] = "HostLogger";
+                asyncResp->res.jsonValue["Entries"] = {
+                    {"@odata.id", "/redfish/v1/Systems/system/LogServices/"
+                                  "HostLogger/Entries"}};
+            });
+}
+
+inline void requestRoutesSystemHostLoggerCollection(App& app)
+{
+    BMCWEB_ROUTE(app,
+                 "/redfish/v1/Systems/system/LogServices/HostLogger/Entries/")
+        .privileges(redfish::privileges::getLogEntry)
+        .methods(boost::beast::http::verb::get)(
+            [](const crow::Request& req,
+               const std::shared_ptr<bmcweb::AsyncResp>& asyncResp) {
+                uint64_t skip = 0;
+                uint64_t top = maxEntriesPerPage; // Show max 1000 entries by
+                                                  // default, allow range 1 to
+                                                  // 1000 entries per page.
+                if (!getSkipParam(asyncResp, req, skip))
+                {
+                    return;
+                }
+                if (!getTopParam(asyncResp, req, top))
+                {
+                    return;
+                }
+                asyncResp->res.jsonValue["@odata.id"] =
+                    "/redfish/v1/Systems/system/LogServices/HostLogger/Entries";
+                asyncResp->res.jsonValue["@odata.type"] =
+                    "#LogEntryCollection.LogEntryCollection";
+                asyncResp->res.jsonValue["Name"] = "HostLogger Entries";
+                asyncResp->res.jsonValue["Description"] =
+                    "Collection of HostLogger Entries";
+                nlohmann::json& logEntryArray =
+                    asyncResp->res.jsonValue["Members"];
+                logEntryArray = nlohmann::json::array();
+
+                std::vector<std::filesystem::path> hostLoggerFiles;
+                if (!getHostLoggerFiles(hostLoggerFolderPath, hostLoggerFiles))
+                {
+                    BMCWEB_LOG_ERROR << "fail to get host log file path";
+                    messages::internalError(asyncResp->res);
+                    return;
+                }
+
+                std::vector<std::string> logEntries;
+                if (!getHostLoggerEntries(hostLoggerFiles, logEntries))
+                {
+                    messages::internalError(asyncResp->res);
+                    return;
+                }
+
+                for (uint64_t id = skip;
+                     id < std::min<uint64_t>(skip + top, logEntries.size());
+                     id++)
+                {
+                    logEntryArray.push_back({});
+                    nlohmann::json& hostLogEntry = logEntryArray.back();
+                    fillHostLoggerEntryJson(std::to_string(id),
+                                            logEntries[static_cast<size_t>(id)],
+                                            hostLogEntry);
+                }
+
+                asyncResp->res.jsonValue["Members@odata.count"] =
+                    logEntries.size();
+                if (skip + top < logEntries.size())
+                {
+                    asyncResp->res.jsonValue["Members@odata.nextLink"] =
+                        "/redfish/v1/Systems/system/LogServices/HostLogger/"
+                        "Entries?skip=" +
+                        std::to_string(skip + top);
+                }
+            });
+}
+
+inline void requestRoutesSystemHostLoggerLogEntry(App& app)
+{
+    BMCWEB_ROUTE(
+        app, "/redfish/v1/Systems/system/LogServices/HostLogger/Entries/<str>/")
+        .privileges(redfish::privileges::getLogEntry)
+        .methods(boost::beast::http::verb::get)(
+            [](const crow::Request&,
+               const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
+               const std::string& param) {
+                const std::string& targetID = param;
+
+                std::vector<std::filesystem::path> hostLoggerFiles;
+                if (!getHostLoggerFiles(hostLoggerFolderPath, hostLoggerFiles))
+                {
+                    BMCWEB_LOG_ERROR << "fail to get host log file path";
+                    messages::internalError(asyncResp->res);
+                    return;
+                }
+
+                std::vector<std::string> logEntries;
+                if (!getHostLoggerEntries(hostLoggerFiles, logEntries))
+                {
+                    messages::internalError(asyncResp->res);
+                    return;
+                }
+
+                uint64_t idInt = 0;
+                auto [ptr, ec] = std::from_chars(
+                    targetID.data(), targetID.data() + targetID.size(), idInt);
+                if (ec == std::errc::invalid_argument)
+                {
+                    messages::resourceMissingAtURI(asyncResp->res, targetID);
+                    return;
+                }
+                if (ec == std::errc::result_out_of_range)
+                {
+                    messages::resourceMissingAtURI(asyncResp->res, targetID);
+                    return;
+                }
+
+                if (idInt < logEntries.size())
+                {
+                    fillHostLoggerEntryJson(
+                        targetID, logEntries[static_cast<size_t>(idInt)],
+                        asyncResp->res.jsonValue);
+                    return;
+                }
+
+                // Requested ID was not found
+                messages::resourceMissingAtURI(asyncResp->res, targetID);
+            });
+}
+
 inline void requestRoutesBMCLogServiceCollection(App& app)
 {
     BMCWEB_ROUTE(app, "/redfish/v1/Managers/bmc/LogServices/")