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Mats^3 Utilities - notably the MatsFuturizer, which provides a bridge from synchronous processes to the highly asynchronous Mats^3 services.
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package io.mats3.util.eagercache;
import static io.mats3.util.eagercache.MatsEagerCacheServer.MatsEagerCacheServerImpl._formatBytes;
import static io.mats3.util.eagercache.MatsEagerCacheServer.MatsEagerCacheServerImpl._formatMillis;
import static io.mats3.util.eagercache.MatsEagerCacheServer.MatsEagerCacheServerImpl._formatTimestamp;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.storebrand.healthcheck.Axis;
import com.storebrand.healthcheck.CheckSpecification.CheckResult;
import com.storebrand.healthcheck.HealthCheckMetadata;
import com.storebrand.healthcheck.HealthCheckMetadata.HealthCheckMetadataBuilder;
import com.storebrand.healthcheck.HealthCheckRegistry;
import com.storebrand.healthcheck.HealthCheckRegistry.RegisteredHealthCheck;
import com.storebrand.healthcheck.Responsible;
import io.mats3.util.eagercache.MatsEagerCacheClient.CacheClientInformation;
import io.mats3.util.eagercache.MatsEagerCacheClient.CacheClientLifecycle;
import io.mats3.util.eagercache.MatsEagerCacheServer.CacheServerInformation;
import io.mats3.util.eagercache.MatsEagerCacheServer.CacheServerLifeCycle;
import io.mats3.util.eagercache.MatsEagerCacheServer.ExceptionEntry;
/**
* HealthCheck for {@link MatsEagerCacheServer} and {@link MatsEagerCacheClient}.
*
* @author Endre Stølsvik 2024-10-02 22:59 - http://stolsvik.com/, [email protected]
*/
public class MatsEagerCacheStorebrandHealthCheck {
private static final Logger log = LoggerFactory.getLogger(MatsEagerCacheStorebrandHealthCheck.class);
/**
* Installs a HealthCheck on the provided {@link HealthCheckRegistry} for the provided {@link MatsEagerCacheServer},
* checking the health of the cache server's.
*
* @param healthCheckRegistry
* The HealthCheckRegistry to register the health check with.
* @param server
* The MatsEagerCacheServer to make a health check for.
* @param responsible
* Responsible parties for the health check, if not provided, defaults to {@link Responsible#DEVELOPERS}.
*/
public static void registerHealthCheck(HealthCheckRegistry healthCheckRegistry,
MatsEagerCacheServer server, CharSequence... responsible) {
CacheServerInformation inf = server.getCacheServerInformation();
String id = "'" + inf.getDataName() + "' @ '" + inf.getNodename() + "'";
String name = "MatsEagerCacheServer " + id;
List registeredHealthChecks = healthCheckRegistry.getRegisteredHealthChecks();
for (RegisteredHealthCheck registeredHealthCheck : registeredHealthChecks) {
if (name.equals(registeredHealthCheck.getMetadata().name)) {
log.error("You're trying to register the same HealthCheck twice for MatsEagerCacheServer " + id
+ ". Ignoring this second time.");
return;
}
}
if (responsible.length == 0) {
responsible = new String[] { Responsible.DEVELOPERS.toString() };
}
final CharSequence[] responsibleF = responsible;
HealthCheckMetadataBuilder meta = HealthCheckMetadata.builder();
meta.name(name);
meta.description("MatsEagerCacheServer: " + id);
meta.sync(true);
healthCheckRegistry.registerHealthCheck(meta.build(), checkSpec -> {
boolean[] serverInstancesHasBeenOk = new boolean[1];
// :: Check: RUNNING
checkSpec.check(responsibleF,
Axis.of(Axis.NOT_READY),
checkContext -> {
CacheServerInformation info = server.getCacheServerInformation();
checkContext.put("info", info);
CheckResult ret;
if (info.getCacheServerLifeCycle() == CacheServerLifeCycle.RUNNING) {
ret = checkContext.ok("Server is RUNNING");
}
else {
ret = checkContext.fault("Server is NOT running - it is '"
+ info.getCacheServerLifeCycle() + "'");
}
return ret;
});
// :: Check: Only one application serving this Cache, and that it is us.
checkSpec.check(responsibleF,
Axis.of(Axis.NOT_READY, Axis.EXTERNAL, Axis.DEGRADED_PARTIAL, Axis.MANUAL_INTERVENTION_REQUIRED),
checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
Map> map = info.getServerAppNamesToNodenames();
CheckResult ret;
if (map.isEmpty()) {
ret = checkContext.fault("Not yet seeing any applications serving the DataName '"
+ info.getDataName() + "!")
.turnOffAxes(Axis.EXTERNAL, Axis.DEGRADED_PARTIAL,
Axis.MANUAL_INTERVENTION_REQUIRED);
}
else if (map.size() == 1) {
String who = map.keySet().iterator().next();
if (info.getAppName().equals(who)) {
ret = checkContext.ok("We're the single application serving DataName '"
+ info.getDataName() + "'");
serverInstancesHasBeenOk[0] = true;
}
else {
ret = checkContext.fault("There is a single application serving DataName '"
+ info.getDataName() + "', but it is not us!");
ret.text(" -> This is REALLY BAD! The app is '" + who + "'.");
ret.text(" -> This means that there is a name-clash between multiple cache servers")
.text(" using the same DataName, living on different applications.");
if (serverInstancesHasBeenOk[0]) {
ret.turnOffAxes(Axis.NOT_READY);
}
}
}
else {
ret = checkContext.fault("There are " + map.size() + " applications serving"
+ " DataName '" + info.getDataName() + "'!");
ret.text(" -> This is REALLY BAD! The apps are " + map.keySet() + ".");
ret.text(" -> This means that there is a name-clash between multiple cache servers")
.text(" using the same DataName, living on different applications.");
if (serverInstancesHasBeenOk[0]) {
ret.turnOffAxes(Axis.NOT_READY);
}
}
return ret;
});
// :: Check: Clients present
checkSpec.check(responsibleF,
Axis.MANUAL_INTERVENTION_REQUIRED,
checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
Map> clientAppNamesToNodenames = info.getClientAppNamesToNodenames();
// ?: Are there any clients?
if (clientAppNamesToNodenames.isEmpty()) {
long timeStarted = info.getCacheStartedTimestamp();
long timeRunning = System.currentTimeMillis() - timeStarted;
int allowedHours = 8;
// Longer than allowed hours since?
boolean longTime = timeRunning > allowedHours * 60 * 60_000;
if (longTime) {
var ret = checkContext.fault("No clients are listening to the Cache Server!");
ret.text(" -> It is more than " + allowedHours
+ " hours since the Cache Server started.");
ret.text(" -> This is most probably not intentional, indicating dead functionality.");
ret.text(" -> The Cache Server must be removed from the application code, or do not");
ret.text(" start it. A temporary solution is to restart the application.");
return ret;
}
else {
return checkContext.ok("No clients are listening to the Cache Server, but it"
+ " is less than " + allowedHours + " hours since it started.");
}
}
else {
int totalNodes = clientAppNamesToNodenames.values().stream().mapToInt(Set::size).sum();
var ret = checkContext.ok("We have clients listening: "
+ clientAppNamesToNodenames.size() + " apps, " + totalNodes + " nodes");
clientAppNamesToNodenames.forEach((app, nodes) -> {
ret.text(" -> " + app + ": " + nodes);
});
return ret;
}
});
// :: Check: Unacknowledged Exceptions
checkSpec.check(responsibleF,
Axis.of(Axis.DEGRADED_PARTIAL, Axis.MANUAL_INTERVENTION_REQUIRED),
checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
List exceptionEntries = info.getExceptionEntries();
// Count unacknowledged exceptions
long unacknowledged = exceptionEntries.stream()
.filter(e -> !e.isAcknowledged())
.count();
CheckResult ret;
if (unacknowledged == 0) {
ret = checkContext.ok("No unacknowledged Exceptions present ("
+ exceptionEntries.size() + " total)");
}
else {
ret = checkContext.fault("There are unacknowledged Exceptions present: "
+ unacknowledged + " of " + exceptionEntries.size());
checkContext.text(" -> Go to the Cache Server's GUI page to resolve and acknowledge them!");
// Add up to 3 of the exceptions to the context
exceptionEntries.stream()
.filter(e -> !e.isAcknowledged())
.limit(3)
.forEach(e -> checkContext.exception(e.getCategory() + ": " + e.getMessage(),
e.getThrowable()));
}
return ret;
});
// --------------------------------------------------------
// :: Add some information about the Cache Server
// Last update sent:
checkSpec.dynamicText(checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
if (info.getLastUpdateSentTimestamp() > 0) {
return "# Last update sent: " + _formatTimestamp(info
.getLastUpdateSentTimestamp())
+ " (" + _formatMillis(System.currentTimeMillis()
- info.getLastUpdateSentTimestamp()) + " ago)";
}
else {
return "# Last update: -I've yet to send any data-";
}
});
// Information about last update sent:
checkSpec.dynamicText(checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
if (info.getLastUpdateDataCount() > 0) {
return "# Data: Count: " + info.getLastUpdateDataCount()
+ ", Uncompressed: " + _formatBytes(info.getLastUpdateUncompressedSize())
+ ", Compressed: " + _formatBytes(info.getLastUpdateCompressedSize());
}
else {
return "# Data: -I've yet to send any data-";
}
});
// Update Received:
checkSpec.dynamicText(checkContext -> {
CacheServerInformation info = checkContext.get("info", CacheServerInformation.class);
if (info.getLastAnyUpdateReceivedTimestamp() == 0) {
return "# Last update received: -I've not yet received any data-";
}
else {
return "# Last update received: " + _formatTimestamp(info
.getLastAnyUpdateReceivedTimestamp())
+ " (" + _formatMillis(System.currentTimeMillis()
- info.getLastAnyUpdateReceivedTimestamp()) + " ago)";
}
});
});
}
/**
* Installs a HealthCheck on the provided {@link HealthCheckRegistry} for the provided {@link MatsEagerCacheClient},
* checking the health of the cache client.
*
* @param healthCheckRegistry
* The HealthCheckRegistry to register the health check with.
* @param client
* The MatsEagerCacheClient to make a health check for.
* @param responsible
* Responsible parties for the health check, if not provided, defaults to {@link Responsible#DEVELOPERS}.
*/
public static void registerHealthCheck(HealthCheckRegistry healthCheckRegistry,
MatsEagerCacheClient client, CharSequence... responsible) {
CacheClientInformation inf = client.getCacheClientInformation();
String id = "'" + inf.getDataName() + "' @ '" + inf.getNodename() + "'";
String name = client instanceof MatsEagerCacheClient.MatsEagerCacheClientMock
? "MatsEagerCacheClient MOCK " + id
: "MatsEagerCacheClient " + id;
List registeredHealthChecks = healthCheckRegistry.getRegisteredHealthChecks();
for (RegisteredHealthCheck registeredHealthCheck : registeredHealthChecks) {
if (name.equals(registeredHealthCheck.getMetadata().name)) {
log.error("You're trying to register the same HealthCheck twice for MatsEagerCacheClient " + id
+ ". Ignoring this second time.");
return;
}
}
if (responsible.length == 0) {
responsible = new String[] { Responsible.DEVELOPERS.toString() };
}
final CharSequence[] responsibleF = responsible;
HealthCheckMetadataBuilder meta = HealthCheckMetadata.builder();
meta.name(name);
meta.description("MatsEagerCacheClient: " + id);
meta.sync(true);
healthCheckRegistry.registerHealthCheck(meta.build(), checkSpec -> {
// :: Check: RUNNING
checkSpec.check(responsibleF,
Axis.of(Axis.NOT_READY),
checkContext -> {
CacheClientInformation info = client.getCacheClientInformation();
checkContext.put("info", info);
if ((info.getCacheClientLifeCycle() == CacheClientLifecycle.RUNNING)
&& info.isInitialPopulationDone()) {
return checkContext.ok("Client is RUNNING, and initial population is done");
}
else {
var ret = checkContext.fault("Client is NOT running - it is '"
+ info.getCacheClientLifeCycle() + "'");
if (info.isInitialPopulationDone()) {
ret.text(" -> Initial population is (somehow!) done.");
}
else {
ret.text(" -> Initial population is NOT done yet.");
}
return ret;
}
});
// :: Check: Server Seen
checkSpec.check(responsibleF,
Axis.of(Axis.DEGRADED_PARTIAL, Axis.MANUAL_INTERVENTION_REQUIRED),
checkContext -> {
CacheClientInformation info = checkContext.get("info", CacheClientInformation.class);
long lastServerSeenTimestamp = info.getLastServerSeenTimestamp();
// 45 min + 1/3 more, as per JavaDoc ..
long maxAdvertisementMinutes = (MatsEagerCacheServer.ADVERTISEMENT_INTERVAL_MINUTES * 4 / 3);
// .. then + 10 minutes for leniency
long maxMinutesAllow = maxAdvertisementMinutes + 10;
String lastAdvertise = "[" + _formatTimestamp(lastServerSeenTimestamp) + ", "
+ _formatMillis(System.currentTimeMillis() - lastServerSeenTimestamp) + " ago]";
long shouldBeWithin = lastServerSeenTimestamp + (maxMinutesAllow * 60_000);
CheckResult ret;
if (System.currentTimeMillis() < shouldBeWithin) {
ret = checkContext.ok("Server last seen " + lastAdvertise + " (max "
+ maxMinutesAllow + " minutes)");
}
else {
ret = checkContext.fault("Servers LOST! Last seen " + lastAdvertise);
checkContext.text(" -> We expect advertise at least every " + maxAdvertisementMinutes
+ " minutes.");
checkContext.text(" -> Next advertise should have been within "
+ _formatTimestamp(shouldBeWithin));
return ret;
}
// Add info about the servers
info.getServerAppNamesToNodenames().forEach((app, nodes) -> {
ret.text(" -> " + app + ": " + nodes);
});
return ret;
});
// :: Check: Unacknowledged Exceptions
checkSpec.check(responsibleF,
Axis.of(Axis.DEGRADED_PARTIAL, Axis.MANUAL_INTERVENTION_REQUIRED),
checkContext -> {
CacheClientInformation info = checkContext.get("info", CacheClientInformation.class);
List exceptionEntries = info.getExceptionEntries();
// Count unacknowledged exceptions
long unacknowledged = exceptionEntries.stream()
.filter(e -> !e.isAcknowledged())
.count();
CheckResult ret;
if (unacknowledged == 0) {
ret = checkContext.ok("No unacknowledged Exceptions present ("
+ exceptionEntries.size() + " total)");
}
else {
ret = checkContext.fault("There are unacknowledged Exceptions present: "
+ unacknowledged + " of " + exceptionEntries.size());
checkContext.text(" -> Go to the Cache Client's GUI page to resolve and acknowledge them!");
// Add up to 3 of the exceptions to the context
exceptionEntries.stream()
.filter(e -> !e.isAcknowledged())
.limit(3)
.forEach(e -> checkContext.exception(e.getCategory() + ": " + e.getMessage(),
e.getThrowable()));
}
return ret;
});
// --------------------------------------------------------
// :: Add some information about the Cache Client
// Update received:
checkSpec.dynamicText(checkContext -> {
CacheClientInformation info = checkContext.get("info", CacheClientInformation.class);
// ?: Is the client running?
if (info.isInitialPopulationDone()) {
return "# Last update: " + _formatTimestamp(info
.getLastAnyUpdateReceivedTimestamp())
+ " (" + _formatMillis(System.currentTimeMillis()
- info.getLastAnyUpdateReceivedTimestamp()) + " ago)";
}
return "# Last update: -Initial population not yet done-";
});
// Information about last update received:
checkSpec.dynamicText(checkContext -> {
CacheClientInformation info = checkContext.get("info", CacheClientInformation.class);
// ?: Have we gotten any data?
if (info.getLastUpdateDataCount() > 0) {
return "# Data: Count: " + info.getLastUpdateDataCount()
+ ", Compressed: " + _formatBytes(info.getLastUpdateCompressedSize())
+ ", Decompressed: " + _formatBytes(info.getLastUpdateDecompressedSize());
}
return "# Data: -No data received yet-";
});
// Number of accesses:
checkSpec.dynamicText(checkContext -> {
CacheClientInformation info = checkContext.get("info", CacheClientInformation.class);
return "# Number of accesses: " + info.getNumberOfAccesses();
});
});
}
}