ansible - 使用 lineinfile 插入行但未按预期工作

Question

我正在使用 lineinfile在 syslog 文件中插入一行。这是我的系统日志:

/var/log/cron
/var/log/maillog
/var/log/messages
/var/log/secure
/var/log/spooler
{
    missingok
    sharedscripts
    postrotate
        /bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null || true
    endscript
}

我要加 compress和 delaycompress之后 missingok .这是我的代码:

- name: "Adding compress line in /etc/logrotate.d/syslog"
  lineinfile:
    path: /etc/logrotate.d/syslog
    insertafter: "^missingok"
    line: "    compress"
    firstmatch: yes
    state: present

- name: "Adding delaycompress line in /etc/logrotate.d/syslog"
  lineinfile:
    path: /etc/logrotate.d/syslog
    insertbefore: "^sharedscripts"
    line: "    delaycompress"
    firstmatch: yes
    state: present

但是它在文件的末尾(最后几行)添加了两者。
备注 : 我在 compress 前加了 4 个空格和 delaycompress .

Answer 1

这是因为插入符号 ^ , 在正则表达式中，匹配字符串的开头而不消耗任何字符。
并且因为您在 missingok 之前确实有空格和 sharedscripts ，您的 insertafter和 insertbefore正则表达式 are matching nothing .
要解决此问题，您可以在 \s 的帮助下仅在行首允许空格和空格。匹配任何空格、制表符或换行符和星号 *匹配零个或多个连续字符。
所以正确的正则表达式是

^\s*missingok

Test it here

^\s*sharedscripts

您的任务的修复将是:

- name: "Adding compress line in /etc/logrotate.d/syslog"
  lineinfile:
    path: /etc/logrotate.d/syslog
    insertafter: "^\\s*missingok"
    line: "    compress"
    firstmatch: yes
    state: present

- name: "Adding delaycompress line in /etc/logrotate.d/syslog"
  lineinfile:
    path: /etc/logrotate.d/syslog
    insertbefore: "^\\s*sharedscripts"
    line: "    delaycompress"
    firstmatch: yes
    state: present

请注意，因为 Ansible 是一个 Python 应用程序， backslashes \ have a special meaning and have to be escaped .