From c821e733644f9521a201157cb94aebc09ef59a8c Mon Sep 17 00:00:00 2001
From: Michael Friedrich <michael.friedrich@icinga.com>
Date: Tue, 16 Apr 2019 16:37:38 +0200
Subject: [PATCH] Cache the API package stage name with a active-stage fallback

This prevents reading the file everytime the stageName is required
for when creating a runtime object via REST API.
---
 doc/15-troubleshooting.md           | 89 ++++++++++++++++++++++++++++-
 doc/16-upgrading-icinga-2.md        | 22 +++++++
 lib/remote/apilistener.cpp          | 55 ++++++++++++++++++
 lib/remote/apilistener.hpp          | 11 ++++
 lib/remote/configpackageutility.cpp | 65 +++++++++++++++++++--
 lib/remote/configpackageutility.hpp |  2 +
 6 files changed, 237 insertions(+), 7 deletions(-)

diff --git a/doc/15-troubleshooting.md b/doc/15-troubleshooting.md
index a4a7b8910..f7d46f7b8 100644
--- a/doc/15-troubleshooting.md
+++ b/doc/15-troubleshooting.md
@@ -747,7 +747,7 @@ $ curl -k -s -u root:icinga -H 'Accept: application/json' -X DELETE 'https://loc
 }
 ```
 
-## REST API Troubleshooting: No Objects Found <a id="troubleshooting-api-no-objects-found"></a>
+### REST API Troubleshooting: No Objects Found <a id="troubleshooting-api-no-objects-found"></a>
 
 Please note that the `404` status with no objects being found can also originate
 from missing or too strict object permissions for the authenticated user.
@@ -761,6 +761,93 @@ In order to analyse and fix the problem, please check the following:
 - use an administrative account with full permissions to check whether the objects are actually there.
 - verify the permissions on the affected ApiUser object and fix them.
 
+### Missing Runtime Objects (Hosts, Downtimes, etc.) <a id="troubleshooting-api-missing-runtime-objects"></a>
+
+Runtime objects consume the internal config packages shared with
+the REST API config packages. Each host, downtime, comment, service, etc. created
+via the REST API is stored in the `_api` package.
+
+This includes downtimes and comments, which where sometimes stored in the wrong
+directory path, because the active-stage file was empty/truncated/unreadable at
+this point.
+
+Wrong:
+
+```
+/var/lib/icinga2/api/packages/_api//conf.d/downtimes/1234-5678-9012-3456.conf
+```
+
+Correct:
+
+```
+/var/lib/icinga2/api/packages/_api/abcd-ef12-3456-7890/conf.d/downtimes/1234-5678-9012-3456.conf
+```
+
+At creation time, the object lives in memory but its storage is broken. Upon restart,
+it is missing and e.g. a missing downtime will re-enable unwanted notifications.
+
+`abcd-ef12-3456-7890` is the active stage name which wasn't correctly
+read by the Icinga daemon. This information is stored in `/var/lib/icinga2/api/packages/_api/active-stage`.
+
+2.11 now limits the direct active-stage file access (this is hidden from the user),
+and caches active stages for packages in-memory.
+
+Bonus on startup/config validation: Icinga now logs a critical message when a deployed
+config package is broken.
+
+```
+icinga2 daemon -C
+
+[2019-04-26 12:58:14 +0200] critical/ApiListener: Cannot detect active stage for package '_api'. Broken config package, check the troubleshooting documentation.
+```
+
+In order to fix the broken config package, and mark a deployed stage as active
+again, carefully do the following steps with creating a backup before:
+
+Navigate into the API package prefix.
+
+```
+cd /var/lib/icinga2/api/packages
+```
+
+Change into the broken package directory and list all directories and files
+ordered by latest changes.
+
+```
+cd _api
+ls -lahtr
+
+drwx------  4 michi  wheel   128B Mar 27 14:39 ..
+-rw-r--r--  1 michi  wheel    25B Mar 27 14:39 include.conf
+-rw-r--r--  1 michi  wheel   405B Mar 27 14:39 active.conf
+drwx------  7 michi  wheel   224B Mar 27 15:01 abcd-ef12-3456-7890
+drwx------  5 michi  wheel   160B Apr 26 12:47 .
+```
+
+As you can see, the `active-stage` file is missing. When it is there, verify that its content
+is set to the stage directory as follows.
+
+If you have more than one stage directory here, pick the latest modified
+directory. Copy the directory name `abcd-ef12-3456-7890` and
+add it into a new file `active-stage`. This can be done like this:
+
+```
+echo "abcd-ef12-3456-7890" > active-stage
+```
+
+Re-run config validation.
+
+```
+icinga2 daemon -C
+```
+
+The validation should not show an error.
+
+> **Note**
+>
+> The internal `_api` config package structure may change in the future. Do not modify
+> things in there manually or with scripts unless guided here or asked by a developer.
+
 
 ## Certificate Troubleshooting <a id="troubleshooting-certificate"></a>
 
diff --git a/doc/16-upgrading-icinga-2.md b/doc/16-upgrading-icinga-2.md
index 665f41b23..377806817 100644
--- a/doc/16-upgrading-icinga-2.md
+++ b/doc/16-upgrading-icinga-2.md
@@ -102,6 +102,28 @@ The deprecated `concurrent_checks` attribute in the [checker feature](09-object-
 has no effect anymore if set. Please use the [MaxConcurrentChecks](17-language-reference.md#icinga-constants-global-config)
 constant in [constants.conf](04-configuring-icinga-2.md#constants-conf) instead.
 
+### REST API <a id="upgrading-to-2-11-api"></a>
+
+#### Config Packages <a id="upgrading-to-2-11-api-config-packages"></a>
+
+Deployed configuration packages require an active stage, with many previous
+allowed. This mechanism is used by the Icinga Director as external consumer,
+and Icinga itself for storing runtime created objects inside the `_api`
+package.
+
+This includes downtimes and comments, which where sometimes stored in the wrong
+directory path, because the active-stage file was empty/truncated/unreadable at
+this point.
+
+2.11 makes this mechanism more stable and detects broken config packages.
+
+```
+[2019-04-26 12:58:14 +0200] critical/ApiListener: Cannot detect active stage for package '_api'. Broken config package, check the troubleshooting documentation.
+```
+
+In order to fix this, please follow [this troubleshooting entry](15-troubleshooting.md#troubleshooting-api-missing-runtime-objects).
+
+
 ## Upgrading to v2.10 <a id="upgrading-to-2-10"></a>
 
 ### Path Constant Changes <a id="upgrading-to-2-10-path-constant-changes"></a>
diff --git a/lib/remote/apilistener.cpp b/lib/remote/apilistener.cpp
index 39d82ef2f..713163d7d 100644
--- a/lib/remote/apilistener.cpp
+++ b/lib/remote/apilistener.cpp
@@ -6,6 +6,7 @@
 #include "remote/endpoint.hpp"
 #include "remote/jsonrpc.hpp"
 #include "remote/apifunction.hpp"
+#include "remote/configpackageutility.hpp"
 #include "base/convert.hpp"
 #include "base/defer.hpp"
 #include "base/io-engine.hpp"
@@ -134,6 +135,9 @@ void ApiListener::OnConfigLoaded()
 		Log(LogWarning, "ApiListener", "Please read the upgrading documentation for v2.8: https://icinga.com/docs/icinga2/latest/doc/16-upgrading-icinga-2/");
 	}
 
+	/* Cache API packages and their active stage name. */
+	UpdateActivePackageStagesCache();
+
 	/* set up SSL context */
 	std::shared_ptr<X509> cert;
 	try {
@@ -1537,6 +1541,57 @@ Endpoint::Ptr ApiListener::GetLocalEndpoint() const
 	return m_LocalEndpoint;
 }
 
+void ApiListener::UpdateActivePackageStagesCache()
+{
+	boost::mutex::scoped_lock lock(m_ActivePackageStagesLock);
+
+	for (auto package : ConfigPackageUtility::GetPackages()) {
+		String activeStage;
+
+		try {
+			activeStage = ConfigPackageUtility::GetActiveStageFromFile(package);
+		} catch (const std::exception& ex) {
+			Log(LogCritical, "ApiListener")
+				<< ex.what();
+			continue;
+		}
+
+		Log(LogNotice, "ApiListener")
+			<< "Updating cache: Config package '" << package << "' has active stage '" << activeStage << "'.";
+
+		m_ActivePackageStages[package] = activeStage;
+	}
+}
+
+void ApiListener::SetActivePackageStage(const String& package, const String& stage)
+{
+	boost::mutex::scoped_lock lock(m_ActivePackageStagesLock);
+	m_ActivePackageStages[package] = stage;
+}
+
+String ApiListener::GetActivePackageStage(const String& package)
+{
+	boost::mutex::scoped_lock lock(m_ActivePackageStagesLock);
+
+	if (m_ActivePackageStages.find(package) == m_ActivePackageStages.end())
+		BOOST_THROW_EXCEPTION(ScriptError("Package " + package + " has no active stage."));
+
+	return m_ActivePackageStages[package];
+}
+
+void ApiListener::RemoveActivePackageStage(const String& package)
+{
+	/* This is the rare occassion when a package has been deleted. */
+	boost::mutex::scoped_lock lock(m_ActivePackageStagesLock);
+
+	auto it = m_ActivePackageStages.find(package);
+
+	if (it == m_ActivePackageStages.end())
+		return;
+
+	m_ActivePackageStages.erase(it);
+}
+
 void ApiListener::ValidateTlsProtocolmin(const Lazy<String>& lvalue, const ValidationUtils& utils)
 {
 	ObjectImpl<ApiListener>::ValidateTlsProtocolmin(lvalue, utils);
diff --git a/lib/remote/apilistener.hpp b/lib/remote/apilistener.hpp
index e6390d944..dcd9e0424 100644
--- a/lib/remote/apilistener.hpp
+++ b/lib/remote/apilistener.hpp
@@ -84,6 +84,11 @@ public:
 	static Value ConfigUpdateObjectAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);
 	static Value ConfigDeleteObjectAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);
 
+	/* API config packages */
+	void SetActivePackageStage(const String& package, const String& stage);
+	String GetActivePackageStage(const String& package);
+	void RemoveActivePackageStage(const String& package);
+
 	static Value HelloAPIHandler(const MessageOrigin::Ptr& origin, const Dictionary::Ptr& params);
 
 	static void UpdateObjectAuthority();
@@ -175,6 +180,12 @@ private:
 	void SendRuntimeConfigObjects(const JsonRpcConnection::Ptr& aclient);
 
 	void SyncClient(const JsonRpcConnection::Ptr& aclient, const Endpoint::Ptr& endpoint, bool needSync);
+
+	/* API Config Packages */
+	mutable boost::mutex m_ActivePackageStagesLock;
+	std::map<String, String> m_ActivePackageStages;
+
+	void UpdateActivePackageStagesCache();
 };
 
 }
diff --git a/lib/remote/configpackageutility.cpp b/lib/remote/configpackageutility.cpp
index fad266b53..c385a5d93 100644
--- a/lib/remote/configpackageutility.cpp
+++ b/lib/remote/configpackageutility.cpp
@@ -1,6 +1,7 @@
 /* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
 
 #include "remote/configpackageutility.hpp"
+#include "remote/apilistener.hpp"
 #include "base/application.hpp"
 #include "base/exception.hpp"
 #include "base/utility.hpp"
@@ -34,6 +35,14 @@ void ConfigPackageUtility::DeletePackage(const String& name)
 	if (!Utility::PathExists(path))
 		BOOST_THROW_EXCEPTION(std::invalid_argument("Package does not exist."));
 
+	ApiListener::Ptr listener = ApiListener::GetInstance();
+
+	/* config packages without API make no sense. */
+	if (!listener)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("No ApiListener instance configured."));
+
+	listener->RemoveActivePackageStage(name);
+
 	Utility::RemoveDirRecursive(path);
 	Application::RequestRestart();
 }
@@ -157,10 +166,7 @@ void ConfigPackageUtility::WriteStageConfig(const String& packageName, const Str
 
 void ConfigPackageUtility::ActivateStage(const String& packageName, const String& stageName)
 {
-	String activeStagePath = GetPackageDir() + "/" + packageName + "/active-stage";
-	std::ofstream fpActiveStage(activeStagePath.CStr(), std::ofstream::out | std::ostream::binary | std::ostream::trunc);
-	fpActiveStage << stageName;
-	fpActiveStage.close();
+	SetActiveStage(packageName, stageName);
 
 	WritePackageConfig(packageName);
 }
@@ -242,8 +248,11 @@ std::vector<String> ConfigPackageUtility::GetStages(const String& packageName)
 	return stages;
 }
 
-String ConfigPackageUtility::GetActiveStage(const String& packageName)
+String ConfigPackageUtility::GetActiveStageFromFile(const String& packageName)
 {
+	/* Lock the transaction, reading this only happens on startup or when something really is broken. */
+	boost::mutex::scoped_lock lock(GetStaticMutex());
+
 	String path = GetPackageDir() + "/" + packageName + "/active-stage";
 
 	std::ifstream fp;
@@ -255,11 +264,55 @@ String ConfigPackageUtility::GetActiveStage(const String& packageName)
 	fp.close();
 
 	if (fp.fail())
-		return "";
+		BOOST_THROW_EXCEPTION(std::invalid_argument("Cannot detect active stage for package '" + packageName + "'. Broken config package, check the troubleshooting documentation."));
 
 	return stage.Trim();
 }
 
+String ConfigPackageUtility::GetActiveStage(const String& packageName)
+{
+	ApiListener::Ptr listener = ApiListener::GetInstance();
+
+	/* config packages without API make no sense. */
+	if (!listener)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("No ApiListener instance configured."));
+
+	String activeStage;
+
+	/* First use runtime state. */
+	try {
+		activeStage = listener->GetActivePackageStage(packageName);
+	} catch (const std::exception& ex) {
+		/* Fallback to reading the file, happens on restarts. */
+		activeStage = GetActiveStageFromFile(packageName);
+
+		/* When we've read something, correct memory. */
+		if (!activeStage.IsEmpty())
+			listener->SetActivePackageStage(packageName, activeStage);
+		else
+			BOOST_THROW_EXCEPTION(std::invalid_argument("Cannot detect active stage for package '" + packageName + "'. Broken config package, check the troubleshooting documentation."));
+	}
+
+	return activeStage;
+}
+
+void ConfigPackageUtility::SetActiveStage(const String& packageName, const String& stageName)
+{
+	ApiListener::Ptr listener = ApiListener::GetInstance();
+
+	/* config packages without API make no sense. */
+	if (!listener)
+		BOOST_THROW_EXCEPTION(std::invalid_argument("No ApiListener instance configured."));
+
+	listener->SetActivePackageStage(packageName, stageName);
+
+	/* Also update the marker on disk for restarts. */
+	String activeStagePath = GetPackageDir() + "/" + packageName + "/active-stage";
+
+	std::ofstream fpActiveStage(activeStagePath.CStr(), std::ofstream::out | std::ostream::binary | std::ostream::trunc); //TODO: fstream exceptions
+	fpActiveStage << stageName;
+	fpActiveStage.close();
+}
 
 std::vector<std::pair<String, bool> > ConfigPackageUtility::GetFiles(const String& packageName, const String& stageName)
 {
diff --git a/lib/remote/configpackageutility.hpp b/lib/remote/configpackageutility.hpp
index db475c8f2..ff1c2ad61 100644
--- a/lib/remote/configpackageutility.hpp
+++ b/lib/remote/configpackageutility.hpp
@@ -32,7 +32,9 @@ public:
 	static String CreateStage(const String& packageName, const Dictionary::Ptr& files = nullptr);
 	static void DeleteStage(const String& packageName, const String& stageName);
 	static std::vector<String> GetStages(const String& packageName);
+	static String GetActiveStageFromFile(const String& packageName);
 	static String GetActiveStage(const String& packageName);
+	static void SetActiveStage(const String& packageName, const String& stageName);
 	static void ActivateStage(const String& packageName, const String& stageName);
 	static void AsyncTryActivateStage(const String& packageName, const String& stageName, bool reload);
 
-- 
2.40.0