Dovecot配置Solr全文搜索时插件缺失及索引无结果问题排查求助

我最近在折腾Dovecot配置Solr全文搜索，跟着官方文档一步步来，Solr用的是8.9.0版本，后台已经能看到创建好的core，配置文件看起来也没啥问题。

不过在执行索引命令的时候遇到了第一个坑：

doveadm fts rescan -u foo@bar.com

直接报错：

Fatal: Plugin 'fts_solr' not found from directory /usr/lib/dovecot/modules

我去模块目录查了下，和fts相关的文件只有这两个：

root@east:/usr/lib/dovecot/modules# ls -lh *fts*
-rw-r--r-- 1 root root 263K Jul  7 17:17 lib20_fts_plugin.so
-rw-r--r-- 1 root root  71K Jul  7 17:17 lib21_fts_squat_plugin.so

这情况我是不是漏装了什么插件？难道需要手动单独安装fts_solr插件吗？对了，我的Dovecot版本是2.3.7.2 (3c910f64b)。

后来我自己查了查，发现确实有个dovecot-fts-solr插件，但尝试安装的时候一直搞不定，甚至想过直接下载.so文件丢到模块目录里，但直觉告诉我这么做肯定行不通，实在不知道该怎么往下走了。

再后来终于找到正确的安装命令：

apt-get install dovecot-solr

安装成功后，模块目录里终于出现了lib21_fts_solr_plugin.so文件。但问题又来了，我重新执行索引命令：

doveadm -D fts rescan -u hello@hatlamp.com

看调试日志，模块确实加载成功了，但去Solr后台一看，还是没有任何文档被索引进去。下面是完整的调试日志：

Debug: Loading modules from directory: /usr/lib/dovecot/modules
Debug: Module loaded: /usr/lib/dovecot/modules/lib20_fts_plugin.so
Debug: Module loaded: /usr/lib/dovecot/modules/lib21_fts_solr_plugin.so
Debug: Loading modules from directory: /usr/lib/dovecot/modules/doveadm
Debug: Skipping module doveadm_acl_plugin, because dlopen() failed: /usr/lib/dovecot/modules/doveadm/lib10_doveadm_acl_plugin.so: undefined symbol: acl_user_module (this is usually intentional, so just ignore this message)
Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib/dovecot/modules/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message)
Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib/dovecot/modules/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message)
Debug: Module loaded: /usr/lib/dovecot/modules/doveadm/lib10_doveadm_sieve_plugin.so
Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib/dovecot/modules/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message)
Debug: Module loaded: /usr/lib/dovecot/modules/doveadm/lib20_doveadm_fts_plugin.so
Debug: Skipping module doveadm_mail_crypt_plugin, because dlopen() failed: /usr/lib/dovecot/modules/doveadm/libdoveadm_mail_crypt_plugin.so: undefined symbol: mail_crypt_box_get_pvt_digests (this is usually intentional, so just ignore this message)
doveadm(hello@hatlamp.com)<35131><>: Debug: auth-master: userdb lookup(hello@hatlamp.com): Started userdb lookup
doveadm(hello@hatlamp.com)<35131><>: Debug: auth-master: conn unix:/var/run/dovecot//auth-userdb: Connecting
doveadm(hello@hatlamp.com)<35131><>: Debug: auth-master: conn unix:/var/run/dovecot//auth-userdb: Client connected (fd=10)
doveadm(hello@hatlamp.com)<35131><>: Debug: auth-master: userdb lookup(hello@hatlamp.com): auth USER input: hello@hatlamp.com uid=1011 gid=8 home=/home/hatlamp quota_rule=*:storage=0M
doveadm(hello@hatlamp.com)<35131><>: Debug: auth-master: userdb lookup(hello@hatlamp.com): Finished userdb lookup (username=hello@hatlamp.com uid=1011 gid=8 home=/home/hatlamp quota_rule=*:storage=0M)
doveadm(hello@hatlamp.com)<35131><>: Debug: Added userdb setting: plugin/quota_rule=*:storage=0M
doveadm(hello@hatlamp.com): Debug: Effective uid=1011, gid=8, home=/home/hatlamp
doveadm(hello@hatlamp.com): Debug: Namespace : type=private, prefix=, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildir:/home/hatlamp/mail/hatlamp.com/hello
doveadm(hello@hatlamp.com): Debug: maildir++: root=/home/hatlamp/mail/hatlamp.com/hello, index=, indexpvt=, control=, inbox=/home/hatlamp/mail/hatlamp.com/hello, alt=
doveadm(hello@hatlamp.com): Debug: auth-master: conn unix:/var/run/dovecot//auth-userdb: Disconnected: Connection closed (fd=10)

有没有大佬能帮我看看这是咋回事啊？

备注：内容来源于stack exchange，提问作者Andrew Newby