Add configuration option for maxSpareThreads

[zxkane]

Below attributes are listed in doc for tomcat,

server.tomcat.access-log-pattern= # log pattern of the access log
server.tomcat.access-log-enabled=false # is access logging enabled
server.tomcat.compression=off # is compression enabled (off, on, or an integer content length limit)
server.tomcat.compressable-mime-types=text/html,text/xml,text/plain # comma-separated list of mime types that Tomcat will compress
server.tomcat.internal-proxies=10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\
        192\\.168\\.\\d{1,3}\\.\\d{1,3}|\\
        169\\.254\\.\\d{1,3}\\.\\d{1,3}|\\
        127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3} # regular expression matching trusted IP addresses
server.tomcat.protocol-header=x-forwarded-proto # front end proxy forward header
server.tomcat.protocol-header-https-value=https # value of the protocol header that indicates that the incoming request uses SSL
server.tomcat.port-header= # front end proxy port header
server.tomcat.remote-ip-header=x-forwarded-for
server.tomcat.basedir=/tmp # base dir (usually not needed, defaults to tmp)
server.tomcat.background-processor-delay=30; # in seconds
server.tomcat.max-http-header-size= # maximum size in bytes of the HTTP message header
server.tomcat.max-threads = 0 # number of threads in protocol handler
server.tomcat.uri-encoding = UTF-8 # character encoding to use for URL decoding

Could you also support more tomcat attributes, such as maxSpareThreads and minSpareThreads?

https://tomcat.apache.org/tomcat-8.0-doc/config/http.html

Or does Spring boot already implicitly support them like server.tomcat.minSpareThreads?

[snicoll]

minSpareThreads does not exist anymore. We provide configuration properties for the most used options, I am not sure maxSpareThreads is one of them. You can always customize the connector yourself by providing your own TomcatEmbeddedServletContainerFactory

[wilkinsona]

maxThreads has always been configurable. minSpareThreads can now be configured too (see 34eb369)