Pooled LdapTemplate stalls for minutes during context validation - grails

Question

I'm trying to use Spring-ldap's LdapTemplate to retrieve information from an LDAP source during a Rest call service implementation and, while I think I have a working configuration, we're noticing stalls of up to 15 minutes intermittently when the service is hit. Logging statements have determined the stall happens during the ldapTemplate.search() call.
My beans:
contextSourceTarget(org.springframework.ldap.core.support.LdapContextSource) {
urls = ["https://someldapsource.com"]
userDn = 'uid=someaccount,ou=xxx,cn=users,dc=org,dc=com'
password = 'somepassword'
pooled = true
}
dirContextValidator(org.springframework.ldap.pool2.validation.DefaultDirContextValidator)
poolConfig( org.springframework.ldap.pool2.factory.PoolConfig ) {
testOnBorrow = true
testWhileIdle = true
}
ldapContextSource(org.springframework.ldap.pool2.factory.PooledContextSource, ref('poolConfig')) {
contextSource = ref('contextSourceTarget')
dirContextValidator = ref('dirContextValidator')
}
ldapTemplate(LdapTemplate, ref('ldapContextSource')) {}
I expect this application could be hitting LDAP several times concurrently (via concurrent rest calls to this app) for retrieving data from different users. Here's the code that makes that call:
List attrs =['uid', 'otherattr1', 'otherattr2']
// this just returns a Map containing the key value pairs of the attrs passed in here.
LdapNamedContextMapper mapper = new LdapNamedContextMapper( attrs )
log.debug( "getLdapUser:preLdapSearch")
List<Map> results = ldapTemplate.search(
'cn=grouproot,cn=Groups,dc=org,dc=com',
'uniquemember=userNameImsearchingfor',
SearchControls.SUBTREE_SCOPE,
attrs as String[], mapper )
log.debug( "getLdapUser:postLdapSearch" )
Unfortunately, at random times it seems, the timestamp difference between the preLdapSearch and postLdapSearch logs is upwards of 15 minutes. Obviously, this is bad, and it would seem to be a pool management issue.
So I turned on debug logging for packages org.springframework.ldap and org.apache.commons.pool2
And now when this happens I get the following in the logs:
2018-09-20 20:18:46.251 DEBUG appEvent="getLdapUser:preLdapSearch"
2018-09-20 20:35:03.246 DEBUG A class javax.naming.ServiceUnavailableException - not explicitly configured to be a non-transient exception - encountered; ignoring.
2018-09-20 20:35:03.249 DEBUG DirContext 'javax.naming.ldap.InitialLdapContext#1f4f37b4' failed validation with an exception.
javax.naming.ServiceUnavailableException: my.ldaphost.com:636; socket closed
at com.sun.jndi.ldap.Connection.readReply(Connection.java:454)
at com.sun.jndi.ldap.LdapClient.getSearchReply(LdapClient.java:638)
at com.sun.jndi.ldap.LdapClient.getSearchReply(LdapClient.java:638)
at com.sun.jndi.ldap.LdapClient.search(LdapClient.java:561)
at com.sun.jndi.ldap.LdapCtx.doSearch(LdapCtx.java:1985)
at com.sun.jndi.ldap.LdapCtx.searchAux(LdapCtx.java:1844)
at com.sun.jndi.ldap.LdapCtx.c_search(LdapCtx.java:1769)
at com.sun.jndi.toolkit.ctx.ComponentDirContext.p_search(ComponentDirContext.java:392)
(LOTS OF STACK TRACE REMOVED)
2018-09-20 20:35:03.249 DEBUG Closing READ_ONLY DirContext='javax.naming.ldap.InitialLdapContext#1f4f37b4'
2018-09-20 20:35:03.249 DEBUG Closed READ_ONLY DirContext='javax.naming.ldap.InitialLdapContext#1f4f37b4'
2018-09-20 20:35:03.249 DEBUG Creating a new READ_ONLY DirContext
2018-09-20 20:35:03.787 DEBUG Created new READ_ONLY DirContext='javax.naming.ldap.InitialLdapContext#5239386d'
2018-09-20 20:35:03.838 DEBUG DirContext 'javax.naming.ldap.InitialLdapContext#5239386d' passed validation.
2018-09-20 20:35:03.890 DEBUG appEvent="getLdapUser:postLdapSearch"
Questions:
How can I find out more? I've got debug logging turned on for org.springframework.ldap and org.apache.commons.pool2
Why is it seeming to take 15+minutes to determine that a connection is stale/unusable? How can I configure to make that much shorter?

Answer 1

There is a good chance that the underlying LDAP system is having connection issues.
You could try adding timeouts in the connection pool settings:
max-wait - default is -1
eviction-run-interval-millis - you may
want to set this to control how often to check for problems
Docs: https://docs.spring.io/spring-ldap/docs/current/reference/#pool-configuration