Detect misuses when you use slf4j and logstash-logback-encoder.
This module provides custom Error Prone checks for slf4j and logstash-logback-encoder. This module doesn't cover all situations in slf4j misuses. So, also use errorprone-slf4j to detect more slf4j misuses.
TBD
dependencies {
annotationProcessor 'io.github.wreulicke.errorprone.logstash:errorprone-logback-logstash-encoder:0.0.1'
# or you can write below when you use net.ltgt.errorprone plugin
errorprone 'io.github.wreulicke.errorprone.logstash:errorprone-logback-logstash-encoder:0.0.1'
}- Slf4jPlaceholderShouldNotContainStructuredArgument
- Slf4jDoNotUsePlaceholder
- Slf4jConstantMarkerMutation
- Slf4jFluentApiFormatShouldBeConst
Slf4jPlaceholderShouldNotContainStructuredArgument rule prevents placeholder contain StructuredArgument. This also detects placeholder mismatch.
This rule conflicts with Slf4jPlaceholderMismatch in errorprone-slf4j. So you should disable the Slf4jPlaceholderMismatch rule if you use this rule.
import org.slf4j.Logger;
import net.logstash.logback.argument.StructuredArguments;
public class Test {
private static final Logger logger = org.slf4j.LoggerFactory.getLogger(Test.class);
public void test() {
// invalid: placeholder should not contain StructuredArgument
logger.info("{}", StructuredArguments.keyValue("key", "value"));
// invalid: count of placeholders does not match with the count of arguments
logger.info("{}");
// valid
logger.info("{}", "safe", StructuredArguments.keyValue("key", "value"));
}
}Slf4jDoNotUsePlaceholder rule prevents using placeholder in log message. This rule is stricter than Slf4jSignOnlyFormat in errorprone-slf4j.
import org.slf4j.Logger;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
import net.logstash.logback.argument.StructuredArguments;
public class Test {
private static final Logger logger = org.slf4j.LoggerFactory.getLogger(Test.class);
private static final Marker MARKER = MarkerFactory.getMarker("marker");
public void test() {
// invalid: format should not contain placeholder. use structured argument instead.
logger.info("some message. userId:{}", "foo");
// valid
logger.info("some message", StructuredArguments.keyValue("userId", "foo"));
}
}Slf4jConstantMarkerMutation rule prevents mutation of constant marker.
import net.logstash.logback.marker.LogstashMarker;
import net.logstash.logback.marker.Markers;
public class Test {
private static final LogstashMarker MARKER = Markers.append("key", "value");
public void test() {
// invalid: Constant marker should not mutate, or use net.logstash.logback.marker.Markers.aggregate instead
MARKER.add(Markers.append("key", "value"));
// valid
Markers.aggregate(MARKER, Markers.append("key", "value"));
}
}Slf4jFluentApiFormatShouldBeConst rule prevents using non-constant format in fluent API. This rule covers Slf4jFormatShouldBeConst in errorprone-slf4j.
import org.slf4j.Logger;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
import net.logstash.logback.argument.StructuredArguments;
public class Test {
private static final Logger logger = org.slf4j.LoggerFactory.getLogger(Test.class);
private static final Marker MARKER = MarkerFactory.getMarker("marker");
public void test() {
// invalid: format should be constant
logger.atInfo().setMessage(() -> "test").log();
// invalid: format should be constant
logger.atInfo().log(() -> "test");
var message = "test";
// invalid: format should be constant
logger.atInfo().log(message);
// invalid: format should be constant
logger.atInfo().setMessage(message).log();
// valid
logger.atInfo().setMessage("safe").log();
// valid
logger.atInfo().log("safe");
}
}- Suggested Fix for Slf4jConstantMarkerMutation
MIT License