作为 rsyslog 属性，spifno1stsp 到底在做什么？
What is spifno1stsp really doing as a rsyslog property?
我正在阅读 rsyslog 的 template documentation 以寻找更好的属性，我偶然发现了这个：
spifno1stsp - expert options for RFC3164 template processing
但是，如您所见，文档非常模糊。此外，我无法在任何地方找到更长的解释。使用 Google 发现的唯一提及总是关于相同的片段或相同的非常简短的描述。
确实这个没有解释属性:
- 在 entire rsyslog.com website、
- 或在 RFC3164、
- 或其他任何地方。
就像每个人都在各处复制和粘贴相同的片段，但很难理解它实际在做什么。
有什么想法吗？
可以把它想象成一个 if 语句。如果 space 存在，则不要执行任何操作。否则，如果 space 不存在 ，请添加 space.
这对于确保仅将一个 space 添加到输出中很有用，通常是在两个字符串之间。
对于任何此类情况，如果您发现可以改进文档的地方，请随时在官方 GitHub rsyslog documentation project 中提出问题并请求澄清。文档团队人手不足，但团队成员会尽力提供帮助。
如果您正在寻找一般帮助，rsyslog-users mailing list 也是一个很好的资源。多年来，我通过查阅档案和阅读之前的话题学到了很多东西。
回到你关于 spifno1stsp 选项的问题：
虽然您会在该选项上获得一些匹配，但您可能会在搜索较旧的字符串模板选项 sp-if-no-1st-sp 时找到更多结果。这是您链接到的文档页面中的一个使用示例：
template(name="forwardFormat" type="string"
string="<%PRI%>%TIMESTAMP:::date-rfc3339% %HOSTNAME% %syslogtag:1:32%%msg:::sp-if-no-1st-sp%%msg%"
)
这里是相关的特定部分：
`%msg:::sp-if-no-1st-sp%%msg%`
来自 Property Replacer 文档：
sp-if-no-1st-sp
This option looks scary and should probably not be used by a user. For
any field given, it returns either a single space character or no
character at all. Field content is never returned. A space is returned
if (and only if) the first character of the field’s content is NOT a
space. This option is kind of a hack to solve a problem rooted in RFC
3164: 3164 specifies no delimiter between the syslog tag sequence and
the actual message text. Almost all implementation in fact delimit the
two by a space. As of RFC 3164, this space is part of the message text
itself. This leads to a problem when building the message (e.g. when
writing to disk or forwarding). Should a delimiting space be included
if the message does not start with one? If not, the tag is immediately
followed by another non-space character, which can lead some log
parsers to misinterpret what is the tag and what the message. The
problem finally surfaced when the klog module was restructured and the
tag correctly written. It exists with other message sources, too. The
solution was the introduction of this special property replacer
option. Now, the default template can contain a conditional space,
which exists only if the message does not start with one. While this
does not solve all issues, it should work good enough in the far
majority of all cases. If you read this text and have no idea of what
it is talking about - relax: this is a good indication you will never
need this option. Simply forget about it ;)
简而言之，sp-if-no-1st-sp（字符串模板选项）类似于spifno1stsp（标准模板选项）。
希望对您有所帮助。
我正在阅读 rsyslog 的 template documentation 以寻找更好的属性，我偶然发现了这个：
spifno1stsp - expert options for RFC3164 template processing
但是，如您所见，文档非常模糊。此外，我无法在任何地方找到更长的解释。使用 Google 发现的唯一提及总是关于相同的片段或相同的非常简短的描述。
确实这个没有解释属性:
- 在 entire rsyslog.com website、
- 或在 RFC3164、
- 或其他任何地方。
就像每个人都在各处复制和粘贴相同的片段，但很难理解它实际在做什么。
有什么想法吗？
可以把它想象成一个 if 语句。如果 space 存在，则不要执行任何操作。否则，如果 space 不存在 ，请添加 space.
这对于确保仅将一个 space 添加到输出中很有用，通常是在两个字符串之间。
对于任何此类情况，如果您发现可以改进文档的地方，请随时在官方 GitHub rsyslog documentation project 中提出问题并请求澄清。文档团队人手不足，但团队成员会尽力提供帮助。
如果您正在寻找一般帮助，rsyslog-users mailing list 也是一个很好的资源。多年来，我通过查阅档案和阅读之前的话题学到了很多东西。
回到你关于 spifno1stsp 选项的问题：
虽然您会在该选项上获得一些匹配，但您可能会在搜索较旧的字符串模板选项 sp-if-no-1st-sp 时找到更多结果。这是您链接到的文档页面中的一个使用示例：
template(name="forwardFormat" type="string"
string="<%PRI%>%TIMESTAMP:::date-rfc3339% %HOSTNAME% %syslogtag:1:32%%msg:::sp-if-no-1st-sp%%msg%"
)
这里是相关的特定部分：
`%msg:::sp-if-no-1st-sp%%msg%`
来自 Property Replacer 文档：
sp-if-no-1st-sp
This option looks scary and should probably not be used by a user. For any field given, it returns either a single space character or no character at all. Field content is never returned. A space is returned if (and only if) the first character of the field’s content is NOT a space. This option is kind of a hack to solve a problem rooted in RFC 3164: 3164 specifies no delimiter between the syslog tag sequence and the actual message text. Almost all implementation in fact delimit the two by a space. As of RFC 3164, this space is part of the message text itself. This leads to a problem when building the message (e.g. when writing to disk or forwarding). Should a delimiting space be included if the message does not start with one? If not, the tag is immediately followed by another non-space character, which can lead some log parsers to misinterpret what is the tag and what the message. The problem finally surfaced when the klog module was restructured and the tag correctly written. It exists with other message sources, too. The solution was the introduction of this special property replacer option. Now, the default template can contain a conditional space, which exists only if the message does not start with one. While this does not solve all issues, it should work good enough in the far majority of all cases. If you read this text and have no idea of what it is talking about - relax: this is a good indication you will never need this option. Simply forget about it ;)
简而言之，sp-if-no-1st-sp（字符串模板选项）类似于spifno1stsp（标准模板选项）。
希望对您有所帮助。