docs: userguide: labels-custom-metadsata.md: update syntax for emtpy value labels

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
This commit is contained in:
Antonio Murdaca 2015-12-16 13:43:41 +01:00
parent bb2c92355c
commit aada8d8117
2 changed files with 16 additions and 8 deletions

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@ -95,14 +95,17 @@ nested properties, the tool itself needs to implement this functionality.
To add labels to an image, use the `LABEL` instruction in your Dockerfile: To add labels to an image, use the `LABEL` instruction in your Dockerfile:
LABEL [<namespace>.]<key>[=<value>] ... LABEL [<namespace>.]<key>=<value> ...
The `LABEL` instruction adds a label to your image, optionally with a value. The `LABEL` instruction adds a label to your image. A `LABEL` consists of a `<key>`
and a `<value>`.
Use an empty string for labels that don't have a `<value>`,
Use surrounding quotes or backslashes for labels that contain Use surrounding quotes or backslashes for labels that contain
white space characters in the `<value>`: white space characters in the `<value>`:
LABEL vendor=ACME\ Incorporated LABEL vendor=ACME\ Incorporated
LABEL com.example.version.is-beta LABEL com.example.version.is-beta=
LABEL com.example.version.is-production=""
LABEL com.example.version="0.0.1-beta" LABEL com.example.version="0.0.1-beta"
LABEL com.example.release-date="2015-02-12" LABEL com.example.release-date="2015-02-12"
@ -114,7 +117,8 @@ in a single instruction:
Long lines can be split up by using a backslash (`\`) as continuation marker: Long lines can be split up by using a backslash (`\`) as continuation marker:
LABEL vendor=ACME\ Incorporated \ LABEL vendor=ACME\ Incorporated \
com.example.is-beta \ com.example.is-beta= \
com.example.is-production="" \
com.example.version="0.0.1-beta" \ com.example.version="0.0.1-beta" \
com.example.release-date="2015-02-12" com.example.release-date="2015-02-12"
@ -130,6 +134,7 @@ You can view the labels via the `docker inspect` command:
"Labels": { "Labels": {
"vendor": "ACME Incorporated", "vendor": "ACME Incorporated",
"com.example.is-beta": "", "com.example.is-beta": "",
"com.example.is-production": "",
"com.example.version": "0.0.1-beta", "com.example.version": "0.0.1-beta",
"com.example.release-date": "2015-02-12" "com.example.release-date": "2015-02-12"
} }
@ -138,7 +143,7 @@ You can view the labels via the `docker inspect` command:
# Inspect labels on container # Inspect labels on container
$ docker inspect -f "{{json .Config.Labels }}" 4fa6e0f0c678 $ docker inspect -f "{{json .Config.Labels }}" 4fa6e0f0c678
{"Vendor":"ACME Incorporated","com.example.is-beta":"","com.example.version":"0.0.1-beta","com.example.release-date":"2015-02-12"} {"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"}
# Inspect labels on images # Inspect labels on images
$ docker inspect -f "{{json .ContainerConfig.Labels }}" myimage $ docker inspect -f "{{json .ContainerConfig.Labels }}" myimage

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@ -156,20 +156,23 @@ A Dockerfile is similar to a Makefile.
the image. the image.
**LABEL** **LABEL**
-- `LABEL <key>[=<value>] [<key>[=<value>] ...]`or -- `LABEL <key>=<value> [<key>=<value> ...]`or
``` ```
LABEL <key>[ <value>] LABEL <key>[ <value>]
LABEL <key>[ <value>] LABEL <key>[ <value>]
... ...
``` ```
The **LABEL** instruction adds metadata to an image. A **LABEL** is a The **LABEL** instruction adds metadata to an image. A **LABEL** is a
key-value pair. To include spaces within a **LABEL** value, use quotes and key-value pair. To specify a **LABEL** without a value, simply use an empty
string. To include spaces within a **LABEL** value, use quotes and
backslashes as you would in command-line parsing. backslashes as you would in command-line parsing.
``` ```
LABEL com.example.vendor="ACME Incorporated" LABEL com.example.vendor="ACME Incorporated"
or
LABEL com.example.vendor "ACME Incorporated" LABEL com.example.vendor "ACME Incorporated"
LABEL com.example.vendor.is-beta ""
LABEL com.example.vendor.is-beta=
LABEL com.example.vendor.is-beta=""
``` ```
An image can have more than one label. To specify multiple labels, separate An image can have more than one label. To specify multiple labels, separate