Merge branch 'develop' into 'main'

Update the site: how to allow to specify a provider in AWS Lambda

See merge request bot-by/slf4j-aws-lambda!21

Author: vitalijr2

readme.md

@@ -170,6 +170,8 @@ https://slf4j-aws-lambda.bot-by.uk/
 Other AWS centric loggers are [SLF4J/Logback Appender][awslambda-logback], [slf4j-simple-lambda][],
 Logback's [CloudWatch appender][cloudwatch-appender] and [CloudWatchLogs Java appender][cloudwatchlogs-java-appender].
 
+See also how to [setup a provider by a system property][setup-provider]
+
 ## Contributing
 
 Please read [Contributing](contributing.md).
@@ -227,3 +229,5 @@ limitations under the License.
 [cloudwatch-appender]: https://github.com/sndyuk/logback-more-appenders
 
 [cloudwatchlogs-java-appender]: https://github.com/boxfuse/cloudwatchlogs-java-appender
+
+[setup-provider]: https://slf4j-aws-lambda.bot-by.uk/setup-provider.html

src/site/markdown/configuration.md

@@ -57,9 +57,12 @@ logLevelSeparator=\\s+
 markerSeparator=\\|
 ```
 
+See also how to [setup a provider by a system property][setup-provider]
 
 [manual]: https://www.slf4j.org/manual.html
 
 [slf4j-simple]: https://www.slf4j.org/api/org/slf4j/simple/SimpleLogger.html
 
 [SimpleDateFormat]: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/text/SimpleDateFormat.html
+
+[setup-provider]: setup-provider.html

src/site/markdown/index.md

@@ -23,6 +23,7 @@ than **logback** (888K).
 * [Acquire][]
 * [Usage][]
 * [Configuration][]
+* [Setup a provider by a system property][setup-provider]
 
 [SLF4J]: https://www.slf4j.org/
 
@@ -41,3 +42,5 @@ than **logback** (888K).
 [Usage]: usage.html
 
 [Configuration]: configuration.html
+
+[setup-provider]: setup-provider.html

src/site/markdown/setup-provider.md

@@ -0,0 +1,19 @@
+# Setup a provider by a system property
+
+[SLF4J 2.0.9][slf4j.provider] allows a provider to be explicitly specified.
+Since AWS Lambda Environment does not provide any configuration options to set what options
+should be used on startup, the [trick is to use the JAVA_TOOL_OPTIONS][java-tool-options-trick]
+environment variable.
+
+If your AWS Java Lambda has some SLF4J providers and you want to point one of them,
+that needs to setup a System property named `slf4j.provider`, as in the following:
+
+![Using JAVA_TOOL_OPTIONS to setup a provider](environment-variable-screenshot.png)
+
+Further reading [AWS Lambda, Developer Guide: Configuring environment variables][configuration-envvars]
+
+[slf4j.provider]: https://jira.qos.ch/browse/SLF4J-450 "[SLF4J-450]: Allow binding to be explicitly specified"
+
+[java-tool-options-trick]: https://zenidas.wordpress.com/recipes/system-properties-for-a-java-lambda-function/ "System properties for a Java Lambda function"
+
+[configuration-envvars]: https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html "Using Lambda environment variables"