【Docker】Dockerfile 最佳实践-LABEL

参考教程：https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

环境

1. virtual box 6.1
2. centos 7.8
3. docker 19.03

LABEL

You can add labels to your image to help organize images by project, record licensing information, to aid in automation, or for other reasons. For each label, add a line beginning with LABEL and with one or more key-value pairs. The following examples show the different acceptable formats. Explanatory comments are included inline.

您可以在镜像上添加标签，以帮助按项目组织镜像，记录许可信息，帮助自动化或其他原因。对于每个标签，添加以 LABEL 开头并带有一个或多个键值对的行。以下示例显示了不同的可接受格式。内嵌包含解释性注释。

Strings with spaces must be quoted or the spaces must be escaped. Inner quote characters ("), must also be escaped.

带有空格的字符串必须用引号引起来，或者必须将空格转义。内引号字符（“"”）也必须转义。

# Set one or more individual labels
LABEL com.example.version="0.0.1-beta"
LABEL vendor1="ACME Incorporated"
LABEL vendor2=ZENITH Incorporated
LABEL com.example.release-date="2015-02-12"
LABEL com.example.version.is-production=""

An image can have more than one label. Prior to Docker 1.10, it was recommended to combine all labels into a single LABEL instruction, to prevent extra layers from being created. This is no longer necessary, but combining labels is still supported.

一个镜像可以有多个标签。在 Docker 1.10 之前，建议将所有标签合并为一个 LABEL 指令，以防止创建额外的层。现在不再需要此操作，但仍支持组合标签。

# Set multiple labels on one line
LABEL com.example.version="0.0.1-beta" com.example.release-date="2015-02-12"

The above can also be written as:
上面也可以写成：

# Set multiple labels at once, using line-continuation characters to break long lines
LABEL vendor=ACME Incorporated 
      com.example.is-beta= 
      com.example.is-production="" 
      com.example.version="0.0.1-beta" 
      com.example.release-date="2015-02-12"

See Understanding object labels for guidelines about acceptable label keys and values. For information about querying labels, refer to the items related to filtering in Managing labels on objects. See also LABEL in the Dockerfile reference.

请参阅了解对象标签了解有关可接受的标签键和值的准则。有关查询标签的信息，请参阅管理对象上的标签中与过滤有关的项目。另请参阅 Dockerfile 参考中的 LABEL。

总结

介绍了 Dockerfile 的 LABEL 指令的最佳实践。