docker inspect 详解

一、功能介绍

docker inspect 会以 json 格式得到 docker 镜像/容器的元数据。

如下，查看mysql镜像的完整元数据：

docker inspect mysql:5.7
[{"Id": "sha256:1d7aba9171693947d53f474014821972bf25d72b7d143ce4af4c8d8484623417","RepoTags": ["mysql:5.7"],"RepoDigests": ["mysql@sha256:d9b934cdf6826629f8d02ea01f28b2c4ddb1ae27c32664b14867324b3e5e1291"],"Parent": "","Comment": "","Created": "2021-09-03T07:25:25.419696974Z","Container": "9979ac05c87381fb984ce556c94ac87ef0b0209eca50e9a0d81d28756557c2ce","ContainerConfig": {"Hostname": "9979ac05c873","Domainname": "","User": "","AttachStdin": false,"AttachStdout": false,"AttachStderr": false,"ExposedPorts": {"3306/tcp": {},"33060/tcp": {}},"Tty": false,"OpenStdin": false,"StdinOnce": false,"Env": ["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","GOSU_VERSION=1.12","MYSQL_MAJOR=5.7","MYSQL_VERSION=5.7.35-1debian10"],"Cmd": ["/bin/sh","-c","#(nop) ","CMD [\"mysqld\"]"],"Image": "sha256:cae8446f5d2e62008d7a1e3bc66ca14ced29fa4c4d0237cf4e6857fd5ca0c18d","Volumes": {"/var/lib/mysql": {}},"WorkingDir": "","Entrypoint": ["docker-entrypoint.sh"],"OnBuild": null,"Labels": {}},"DockerVersion": "20.10.7","Author": "","Config": {"Hostname": "","Domainname": "","User": "","AttachStdin": false,"AttachStdout": false,"AttachStderr": false,"ExposedPorts": {"3306/tcp": {},"33060/tcp": {}},"Tty": false,"OpenStdin": false,"StdinOnce": false,"Env": ["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","GOSU_VERSION=1.12","MYSQL_MAJOR=5.7","MYSQL_VERSION=5.7.35-1debian10"],"Cmd": ["mysqld"],"Image": "sha256:cae8446f5d2e62008d7a1e3bc66ca14ced29fa4c4d0237cf4e6857fd5ca0c18d","Volumes": {"/var/lib/mysql": {}},"WorkingDir": "","Entrypoint": ["docker-entrypoint.sh"],"OnBuild": null,"Labels": null},"Architecture": "amd64","Os": "linux","Size": 448211969,"VirtualSize": 448211969,"GraphDriver": {"Data": {"RootDir": "/var/lib/docker/overlay/e96512345b168f8f1f03e341bdc1e305687a8a54eefab1dfd5e21665ee01933a/root"},"Name": "overlay"},"RootFS": {"Type": "layers","Layers": ["sha256:d000633a56813933cb0ac5ee3246cf7a4c0205db6290018a169d7cb096581046","sha256:731f7c21360385893ff752e1200bf901f7936f973801eb6f10dc81f249920994","sha256:b2830993d63aac4a4c4c3cdea0ccae39c14d53e69d82d4a6541b35670431f244","sha256:97a2a3481f0d61f26f855842ffb8170680a68659ab724042b3a000941a5a0a4e","sha256:35e94dafc854af4a22dd101bc5f6b0b453c91d50ef9893228ae9b41d5fd99226","sha256:2eaac5532d4479e5e821f724c854b8bc38527708ff484397b841561e21a8fc9a","sha256:89638afc97cdd7709e24a927a87520751464fbb3af9b564e591f0a783b6276fc","sha256:71cabb0b234c522858b8398181aac5ff1a98ec6be8ba71c4079a3cb093f6b4de","sha256:b09979068448d00f4513f2bb8b5a4e3734bbbddc526ed5205fbd52f442727167","sha256:67536a20af848ab1861ea5e5bf336e223a474e7c411bf21761b8b55f40bde9b9","sha256:7449e60227868d770c9fd6437a85717bd6d09667e1e066190af887f687c62372"]},"Metadata": {"LastTagTime": "0001-01-01T00:00:00Z"}}
]

如下为以mysql:5.7启动的容器的完整元数据：

docker run -itd mysql:5.7 /bin/sh
492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3docker inspect 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
[{"Id": "492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3","Created": "2022-06-13T09:01:22.321391083Z","Path": "docker-entrypoint.sh","Args": ["/bin/sh"],"State": {"Status": "running","Running": true,"Paused": false,"Restarting": false,"OOMKilled": false,"Dead": false,"Pid": 48552,"ExitCode": 0,"Error": "","StartedAt": "2022-06-13T09:01:22.584406847Z","FinishedAt": "0001-01-01T00:00:00Z"},"Image": "sha256:1d7aba9171693947d53f474014821972bf25d72b7d143ce4af4c8d8484623417","ResolvConfPath": "/var/lib/docker/containers/492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3/resolv.conf","HostnamePath": "/var/lib/docker/containers/492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3/hostname","HostsPath": "/var/lib/docker/containers/492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3/hosts","LogPath": "/var/lib/docker/containers/492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3/492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3-json.log","Name": "/silly_antonelli","RestartCount": 0,"Driver": "overlay","Platform": "linux","MountLabel": "","ProcessLabel": "","AppArmorProfile": "","ExecIDs": null,"HostConfig": {"Binds": null,"ContainerIDFile": "","LogConfig": {"Type": "json-file","Config": {"max-file": "10","max-size": "100m"}},"NetworkMode": "default","PortBindings": {},"RestartPolicy": {"Name": "no","MaximumRetryCount": 0},"AutoRemove": false,"VolumeDriver": "","VolumesFrom": null,"CapAdd": null,"CapDrop": null,"CgroupnsMode": "host","Dns": [],"DnsOptions": [],"DnsSearch": [],"ExtraHosts": null,"GroupAdd": null,"IpcMode": "private","Cgroup": "","Links": null,"OomScoreAdj": 0,"PidMode": "","Privileged": false,"PublishAllPorts": false,"ReadonlyRootfs": false,"SecurityOpt": null,"UTSMode": "","UsernsMode": "","ShmSize": 67108864,"Runtime": "runc","ConsoleSize": [0,0],"Isolation": "","CpuShares": 0,"Memory": 0,"NanoCpus": 0,"CgroupParent": "","BlkioWeight": 0,"BlkioWeightDevice": [],"BlkioDeviceReadBps": null,"BlkioDeviceWriteBps": null,"BlkioDeviceReadIOps": null,"BlkioDeviceWriteIOps": null,"CpuPeriod": 0,"CpuQuota": 0,"CpuRealtimePeriod": 0,"CpuRealtimeRuntime": 0,"CpusetCpus": "","CpusetMems": "","Devices": [],"DeviceCgroupRules": null,"DeviceRequests": null,"KernelMemory": 0,"KernelMemoryTCP": 0,"MemoryReservation": 0,"MemorySwap": 0,"MemorySwappiness": null,"OomKillDisable": false,"PidsLimit": null,"Ulimits": [{"Name": "NOFILE","Hard": 655350,"Soft": 655350}],"CpuCount": 0,"CpuPercent": 0,"IOMaximumIOps": 0,"IOMaximumBandwidth": 0,"MaskedPaths": ["/proc/asound","/proc/acpi","/proc/kcore","/proc/keys","/proc/latency_stats","/proc/timer_list","/proc/timer_stats","/proc/sched_debug","/proc/scsi","/sys/firmware"],"ReadonlyPaths": ["/proc/bus","/proc/fs","/proc/irq","/proc/sys","/proc/sysrq-trigger"]},"GraphDriver": {"Data": {"LowerDir": "/var/lib/docker/overlay/e96512345b168f8f1f03e341bdc1e305687a8a54eefab1dfd5e21665ee01933a/root","MergedDir": "/var/lib/docker/overlay/3fbd4444a83b03d8684acd87e38bcaac658d4e038f6e27aaabc10b20152f1563/merged","UpperDir": "/var/lib/docker/overlay/3fbd4444a83b03d8684acd87e38bcaac658d4e038f6e27aaabc10b20152f1563/upper","WorkDir": "/var/lib/docker/overlay/3fbd4444a83b03d8684acd87e38bcaac658d4e038f6e27aaabc10b20152f1563/work"},"Name": "overlay"},"Mounts": [{"Type": "volume","Name": "cb8a9a3d23814b91df3566e7b14b355cc381aa5719297907a68f6d99a1472294","Source": "/var/lib/docker/volumes/cb8a9a3d23814b91df3566e7b14b355cc381aa5719297907a68f6d99a1472294/_data","Destination": "/var/lib/mysql","Driver": "local","Mode": "","RW": true,"Propagation": ""}],"Config": {"Hostname": "492c91fb2b8f","Domainname": "","User": "","AttachStdin": false,"AttachStdout": false,"AttachStderr": false,"ExposedPorts": {"3306/tcp": {},"33060/tcp": {}},"Tty": true,"OpenStdin": true,"StdinOnce": false,"Env": ["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","GOSU_VERSION=1.12","MYSQL_MAJOR=5.7","MYSQL_VERSION=5.7.35-1debian10"],"Cmd": ["/bin/sh"],"Image": "mysql:5.7","Volumes": {"/var/lib/mysql": {}},"WorkingDir": "","Entrypoint": ["docker-entrypoint.sh"],"OnBuild": null,"Labels": {}},"NetworkSettings": {"Bridge": "","SandboxID": "a2f0fe86422968b0c5e1d0b7e4dd66a742dedfc8b01b56eb30649449969f4f12","HairpinMode": false,"LinkLocalIPv6Address": "","LinkLocalIPv6PrefixLen": 0,"Ports": {"3306/tcp": null,"33060/tcp": null},"SandboxKey": "/data/docker/exec/netns/a2f0fe864229","SecondaryIPAddresses": null,"SecondaryIPv6Addresses": null,"EndpointID": "d41dfa3aadb23af2c459845e9ba11e87a13e7d96e170c879b6b14db76d443168","Gateway": "172.17.0.1","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"IPAddress": "172.17.0.4","IPPrefixLen": 16,"IPv6Gateway": "","MacAddress": "02:42:ac:11:00:04","Networks": {"bridge": {"IPAMConfig": null,"Links": null,"Aliases": null,"NetworkID": "9cbe344a6886a489cd1b3d4cef5befc454d477d4c5ac59756d8bdf579739f20a","EndpointID": "d41dfa3aadb23af2c459845e9ba11e87a13e7d96e170c879b6b14db76d443168","Gateway": "172.17.0.1","IPAddress": "172.17.0.4","IPPrefixLen": 16,"IPv6Gateway": "","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"MacAddress": "02:42:ac:11:00:04","DriverOpts": null}}}}
]

二、参数说明

2.1、`-f`

通常我们需要获取某一个具体的key，会用grep，如下，grep会获取到其他的数据，不够完整或者有冗余，还得进一步处理，但是 -f 可以解决这个问题：

docker inspect mysql:5.7 | grep Layers"Layers": [docker inspect mysql:5.7 | grep -A 30 Layers"Layers": ["sha256:d000633a56813933cb0ac5ee3246cf7a4c0205db6290018a169d7cb096581046","sha256:731f7c21360385893ff752e1200bf901f7936f973801eb6f10dc81f249920994","sha256:b2830993d63aac4a4c4c3cdea0ccae39c14d53e69d82d4a6541b35670431f244","sha256:97a2a3481f0d61f26f855842ffb8170680a68659ab724042b3a000941a5a0a4e","sha256:35e94dafc854af4a22dd101bc5f6b0b453c91d50ef9893228ae9b41d5fd99226","sha256:2eaac5532d4479e5e821f724c854b8bc38527708ff484397b841561e21a8fc9a","sha256:89638afc97cdd7709e24a927a87520751464fbb3af9b564e591f0a783b6276fc","sha256:71cabb0b234c522858b8398181aac5ff1a98ec6be8ba71c4079a3cb093f6b4de","sha256:b09979068448d00f4513f2bb8b5a4e3734bbbddc526ed5205fbd52f442727167","sha256:67536a20af848ab1861ea5e5bf336e223a474e7c411bf21761b8b55f40bde9b9","sha256:7449e60227868d770c9fd6437a85717bd6d09667e1e066190af887f687c62372"]},"Metadata": {"LastTagTime": "0001-01-01T00:00:00Z"}}
]

docker inspect -f '{{.RootFS.Layers}}' mysql:5.7
[sha256:d000633a56813933cb0ac5ee3246cf7a4c0205db6290018a169d7cb096581046 sha256:731f7c21360385893ff752e1200bf901f7936f973801eb6f10dc81f249920994 sha256:b2830993d63aac4a4c4c3cdea0ccae39c14d53e69d82d4a6541b35670431f244 sha256:97a2a3481f0d61f26f855842ffb8170680a68659ab724042b3a000941a5a0a4e sha256:35e94dafc854af4a22dd101bc5f6b0b453c91d50ef9893228ae9b41d5fd99226 sha256:2eaac5532d4479e5e821f724c854b8bc38527708ff484397b841561e21a8fc9a sha256:89638afc97cdd7709e24a927a87520751464fbb3af9b564e591f0a783b6276fc sha256:71cabb0b234c522858b8398181aac5ff1a98ec6be8ba71c4079a3cb093f6b4de sha256:b09979068448d00f4513f2bb8b5a4e3734bbbddc526ed5205fbd52f442727167 sha256:67536a20af848ab1861ea5e5bf336e223a474e7c411bf21761b8b55f40bde9b9 sha256:7449e60227868d770c9fd6437a85717bd6d09667e1e066190af887f687c62372]# 格式要求
'{{.一级key值.二级key值}}'# 容器同样适用
docker inspect -f '{{.Config.Env}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
[PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin GOSU_VERSION=1.12 MYSQL_MAJOR=5.7 MYSQL_VERSION=5.7.35-1debian10]

2.2、`--type`

指定具体类型如：–type container 声明查看容器的元数据

docker inspect --type container 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
[{"Id": "492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3","Created": "2022-06-13T09:01:22.321391083Z","Path": "docker-entrypoint.sh","Args": ["/bin/sh"],"State": {"Status": "running","Running": true,"Paused": false,"Restarting": false,"OOMKilled": false,"Dead": false,"Pid": 48552,"ExitCode": 0,"Error": "","StartedAt": "2022-06-13T09:01:22.584406847Z","FinishedAt": "0001-01-01T00:00:00Z"},
...

docker inspect --type image mysql:5.7
[{"Id": "sha256:1d7aba9171693947d53f474014821972bf25d72b7d143ce4af4c8d8484623417","RepoTags": ["mysql:5.7"],"RepoDigests": ["mysql@sha256:d9b934cdf6826629f8d02ea01f28b2c4ddb1ae27c32664b14867324b3e5e1291"],"Parent": "","Comment": "","Created": "2021-09-03T07:25:25.419696974Z","Container": "9979ac05c87381fb984ce556c94ac87ef0b0209eca50e9a0d81d28756557c2ce","ContainerConfig": {"Hostname": "9979ac05c873","Domainname": "","User": "","AttachStdin": false,"AttachStdout": false,"AttachStderr": false,"ExposedPorts": {"3306/tcp": {},"33060/tcp": {}},
...

2.3、`-s`

显示总的文件大小

docker inspect -s 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3 | grep Size"ShmSize": 67108864,"ConsoleSize": ["SizeRw": 37,"SizeRootFs": 448212006,docker inspect  492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3 | grep Size"ShmSize": 67108864,"ConsoleSize": [

三、docker inspect -f 更多用法

简单地说，-f 的实参是个 Go 模版，并在容器/镜像的元数据上以该 Go 模版作为输入，最终返回模版指定的数据。Go 模版是一种模板引擎，让数据以指定的模式输出。这个概念对于 Web 开发者是非常熟悉的，Web 领域有很多模版引擎，比如 Jinga2（用于 Python 和 Flask）、Mustache、JSP 等等，看下面的简单示例:

docker inspect -f "The image's repotags is {{.RepoTags}}" mysql:5.7
The image's repotags is [mysql:5.7]

3.1、Go 模版详解

模版指令
{{ }} 语法用于处理模版指令，大括号外的任何字符都将直接输出。

上下文
“.” 表示“当前上下文”。大多数情况下表示了容器元数据的整个数据结构，但在某些情况下可以重新规定上下文，比如使用 with 函数：

docker inspect -f '{{.State.Pid}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
48552docker inspect -f '{{with .State}} {{.Pid}} {{end}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db348552

可以使用 $ 来获取根上下文,只能获取一级key值

docker inspect -f '{{$.Name}} has pid {{with .State}} {{.Pid}} {{end}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
/silly_antonelli has pid  48552

注意，单独使用 “.” 本身也是可以的，将输出未格式化的完整元数据：

3.2、数据类型

inspect 数据可以由浮点数、字符串和布尔组成，可以使用 Go 模版内置函数进行比较判断。虽然 Go 模版支持整数，但目前 inspect 数据中的数值类型都是浮点数，而整数应该对于大多数场景更方便（详见该Issue）。使用字符串时可以使用双引号。

数据中不存在的值是不可以用来比较的：

docker inspect -f '{{.ExecIDs}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
[]docker inspect 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3 | grep ExecIDs"ExecIDs": null,docker inspect -f '{{eq .ExecIDs .ExecIDs}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <eq .ExecIDs .ExecIDs>: error calling eq: invalid type for comparison

3.3、数据结构

inspect 数据使用 map 以及数组保存。Map 结构可以通过 . 的链式来访问 map 内部数据：

docker inspect -f '{{.State.ExitCode}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
0

3.3.1、如果需要获取的属性名称包含 “/”（比如下列示例数据）或者以数字开头，则不能直接通过级联调用获取信息。因为属性名称中的点号会被解析成级联信息，进而导致返回错误结果。即便使用引号将其包含也会提示语法格式错误。此时，需要通过 index 来读取指定属性信息。前面卷的例子可以这样写：

docker inspect -f '{{.Config.Volumes./var/lib/mysql}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
Template parsing error: template: :1: bad character U+002F '/'# 双引号也不行
docker inspect -f '{{.NetworkSettings.Ports.3306/tcp}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
Template parsing error: template: :1: unexpected ".3306" in operand#docker inspect -f '{{.NetworkSettings.Ports."3306/tcp"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
Template parsing error: template: :1: bad character U+0022 '"'# 正确写法   ！！！注意 index 与之后的数据之间包含空格，与之后双引号括起来的也有空格，否则报错
docker inspect -f '{{index .NetworkSettings.Ports "3306/tcp"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
<no value>docker inspect -f '{{index .Config.Volumes "/var/lib/mysql"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
{}#报错如下
docker inspect -f '{{index.NetworkSettings.Ports "3306/tcp"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <index>: wrong number of args for index: want at least 1 got 0

3.3.2、如果返回结果是一个 map, slice, array 或 string，则可以使用 index 加索引序号（从零开始计数）来读取属性值

docker inspect -f '{{.HostConfig.ReadonlyPaths}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
[/proc/bus /proc/fs /proc/irq /proc/sys /proc/sysrq-trigger]docker inspect -f '{{index .HostConfig.ReadonlyPaths 0}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
/proc/bus# 另一种类型，包含多个键值对的获取
想要获取EndpointID的值：
"NetworkSettings": {"Bridge": "","SandboxID": "a2f0fe86422968b0c5e1d0b7e4dd66a742dedfc8b01b56eb30649449969f4f12","HairpinMode": false,"LinkLocalIPv6Address": "","LinkLocalIPv6PrefixLen": 0,"Ports": {"3306/tcp": null,"33060/tcp": null},"SandboxKey": "/data/docker/exec/netns/a2f0fe864229","SecondaryIPAddresses": null,"SecondaryIPv6Addresses": null,"EndpointID": "d41dfa3aadb23af2c459845e9ba11e87a13e7d96e170c879b6b14db76d443168","Gateway": "172.17.0.1","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"IPAddress": "172.17.0.4","IPPrefixLen": 16,"IPv6Gateway": "","MacAddress": "02:42:ac:11:00:04","Networks": {"bridge": {"IPAMConfig": null,"Links": null,"Aliases": null,"NetworkID": "9cbe344a6886a489cd1b3d4cef5befc454d477d4c5ac59756d8bdf579739f20a","EndpointID": "d41dfa3aadb23af2c459845e9ba11e87a13e7d96e170c879b6b14db76d443168","Gateway": "172.17.0.1","IPAddress": "172.17.0.4","IPPrefixLen": 16,"IPv6Gateway": "","GlobalIPv6Address": "","GlobalIPv6PrefixLen": 0,"MacAddress": "02:42:ac:11:00:04","DriverOpts": null}}}docker inspect -f '{{index .NetworkSettings.Networks.bridge 4}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <index .NetworkSettings.Networks.bridge 4>: error calling index: value has type int; should be stringdocker inspect -f '{{index .NetworkSettings.Networks.bridge "4"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
<no value>docker inspect -f '{{index .NetworkSettings.Networks.bridge "EndpointID"}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
d41dfa3aadb23af2c459845e9ba11e87a13e7d96e170c879b6b14db76d443168

3.4、函数

除了 index 函数，其他很多函数也很常用。比如逻辑函数 and、or 可以返回布尔结果。注意，函数是不能放在中间：

docker inspect -f '{{true and true}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <true>: can't give argument to non-function truedocker inspect -f '{{and true true}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
true

下面是一些常用的比较函数：

eq (等于)
ne (不等于)
lt (小于)
le (小于等于)
gt (大于)
ge (大于等于)

我们可以用这些函数来比较字符串、浮点数或整数：

docker inspect -f '{{and true true}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
truedocker inspect -f '{{eq "abc" "abc"}}'  492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
truedocker inspect -f '{{ge 1 3}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
falsedocker inspect -f '{{lt 4.5 4.6}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
truedocker inspect -f '{{ne 4.5 4.5}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
false

要注意的是操作数类型必须匹配，数字比较时也需要类型匹配：

docker inspect -f '{{ne 4 4.5}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <ne 4 4.5>: error calling ne: incompatible types for comparisondocker inspect -f '{{lt 4.5 4.6}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
truedocker inspect -f '{{gt .State.Pid 1}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
truedocker inspect -f '{{gt .State.Pid 1.0}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Template parsing error: template: :1:2: executing "" at <gt .State.Pid 1.0>: error calling gt: incompatible types for comparison

比较特殊的是，它支持多个参数进行与比较，此时，它会将第一个参数和其余参数依次比较，返回下式的结果：

{{if eq true .Var1 .Var2 .Var3}}{{end}}
# 效果等同于：
arg1==arg2 || arg1==arg3 || arg1==arg4

另外，可以使用 json 函数来生成 JSON 输出：

docker inspect -f '{{json .NetworkSettings.Ports}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3
{"3306/tcp":null,"33060/tcp":null}

3.5、if 语句

条件语句 if 可以和前面的比较函数一起使用：

docker inspect -f '{{if eq .State.ExitCode 0}} Normal Exit {{else if eq .State.ExitCode 1}} Not a Normal Exit {{else}} Still Not a Normal Exit {{end}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Normal Exit

优化显示后为：

$ docker inspect -f '{{if eq .State.ExitCode 0}}
Normal Exit
{{else if eq .State.ExitCode 1}}
Not a Normal Exit
{{else}}
Still Not a Normal Exit
{{end}}' 492c91fb2b8ff1a334fcd64ba3e46585701e7e5809f564bc2c65f3a655458db3Normal Exit    //假设ExitCode为0时的结果

注意，{{end}} 语句必须有，else if 和 else 按需使用。

3.6、range迭代数据

range 用于遍历结构内返回值的所有数据。支持的类型包括 array, slice, map 和 channel。使用要点：

对应的值长度为 0 时，range 不会执行。
结构内部如要使用外部的变量，需要在前面加 引用，比如Var2。
range 也支持 else 操作。效果是：当返回值为空或长度为 0 时执行 else 内的内容。

{{range pipeline}}{{.}}{{end}}
{{range pipeline}}{{.}}{{else}}{{.}}{{end}}* 查看容器网络下已挂载的所有容器名称，如果没有挂载任何容器，则输出 "With No Containers"
docker inspect --format '{{range .Containers}}{{.Name}}{{println}}{{else}}With No Containers{{end}}' bridge
brtest
peaceful_brown
testdocker inspect --format '{{range .Containers}}{{.Name}}{{println}}{{else}}With No Containers{{end}}' none
With No Containers
1234567891011

3.7、打印信息

docker --format 默认调用 go语言的 print 函数对模板中的字符串进行输出。而 go语言还有另外几种相似的内置函数，对比说明如下：

print： 将传入的对象转换为字符串并写入到标准输出中。如果后跟多个参数，输出结果之间会自动填充空格进行分隔。
println: 功能和 print 类似，但会在结尾添加一个换行符。也可以直接使用 {{println}} 来换行。
printf: 与 shell 等环境一致，可配合占位符用于格式化输出。

docker inspect --format '{{.State.Pid}}{{.State.ExitCode}}' $INSTANCE_ID
240390docker inspect --format '{{print .State.Pid .State.ExitCode}}' $INSTANCE_ID
24039 0docker inspect --format '{{.State.Pid}}{{println " 从这换行"}}{{.State.ExitCode}}' $INSTANCE_ID
24039 从这换行
0docker inspect --format '{{printf "Pid:%d ExitCode:%d" .State.Pid .State.ExitCode}}' $INSTANCE_ID
Pid:24039 ExitCode:0
123456789101112

3.8、管道

管道即 pipeline ，与 shell 中类似，可以是上下文的变量输出，也可以是函数通过管道传递的返回值。

{{.Con | markdown | addlinks}}
{{.Name | printf "%s"}}

3.9、Docker内置函数

3.9.1、 json

Docker 默认以字符串显示返回结果。而该函数可以将结果格式化为压缩后的 json 格式数据。

# 获取 Config 字段对应的 json 数据
docker inspect --format='{{json .Config}}' $INSTANCE_ID

3.9.2、 join

用指定的字符串将返回结果连接后一起展示。操作对象必须是字符串数组

# 输出容器配置的所有 Entrypoint 参数，以 " , " 分隔：
docker inspect --format '{{join .Config.Entrypoint " , "}}' $INSTANCE_ID

3.9.3、 lower

将返回结果中的字母全部转换为小写。操作对象必须是字符串。

docker inspect --format "{{lower .Name}}" $INSTANCE_ID

3.9.4、upper

将返回结果中的字母全部转换为大写。操作对象必须是字符串。

docker inspect --format "{{lower .Name}}" $INSTANCE_ID

3.9.5、 title

将返回结果的首字母转换为大写。操作对象必须是字符串，而且不能是纯数字。

docker inspect --format "{{title .State.Status}}" $INSTANCE_ID

3.9.6、split

使用指定分隔符将返回结果拆分为字符串列表。操作对象必须是字符串且不能是纯数字。同时，字符串中必须包含相应的分隔符，否则会直接忽略操作。

docker inspect --format '{{split .HostsPath "/"}}' $INSTANCE_ID

3.10、常用docker inspect --format 输出示例

$ docker ps
CONTAINER ID        IMAGE                            COMMAND                  CREATED             STATUS              PORTS               NAMES
2ed603e52896        172.16.60.214:5000/nginx   "/bin/sh -c '/usr/..."   13 minutes ago      Up 13 minutes                           docker-test111
24e6607534f1        172.16.60.214:5000/nginx   "/bin/sh -c '/usr/..."   13 minutes ago      Up 13 minutes                           docker-test11
19be6b264b6e        172.16.60.214:5000/nginx   "/bin/sh -c '/usr/..."   13 minutes ago      Up 13 minutes                           docker-test11) 获取容器的IP (后面使用容器名或容器ID都可以)
$ docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $(docker ps -q)
192.10.160.193
173.20.19.128
17.16.10.128$ docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' docker-test1
17.16.10.1282) 获取容器的MAC地址
$ docker inspect --format='{{range .NetworkSettings.Networks}}{{.MacAddress}}{{end}}' $(docker ps -a -q)
ee:ee:ee:ee:ee:ee
ee:ee:ee:ee:ee:ee
ee:ee:ee:ee:ee:ee[root@node1 ~]# docker inspect --format='{{range .NetworkSettings.Networks}}{{.MacAddress}}{{end}}' docker-test1
ee:ee:ee:ee:ee:ee3) 获取容器Name
$ docker inspect --format='{{.Name}}' $(docker ps -aq)
/docker-test111
/docker-test11
/docker-test1
/calico-node$ docker inspect --format='{{.Name}}' $(docker ps -aq)|cut -d"/" -f2
docker-test111
docker-test11
docker-test1$ docker inspect --format='{{.Name}}' docker-test1
/docker-test1$ docker inspect --format='{{.Name}}' docker-test1|cut -d"/" -f2
docker-test14) 获取容器Hostname
$ docker inspect --format '{{ .Config.Hostname }}' $(docker ps -q)
2ed603e52896
24e6607534f1
19be6b264b6e$ docker inspect --format '{{ .Config.Hostname }}' docker-test1
19be6b264b6e5) Hostname Name IP
$ docker inspect --format 'Hostname:{{ .Config.Hostname }}  Name:{{.Name}} IP:{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $(docker ps -q)
Hostname:2ed603e52896  Name:/docker-test111 IP:192.10.160.193
Hostname:24e6607534f1  Name:/docker-test11 IP:173.20.19.128
Hostname:19be6b264b6e  Name:/docker-test1 IP:17.16.10.128$ docker inspect --format 'Hostname:{{ .Config.Hostname }}  Name:{{.Name}} IP:{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' docker-test1
Hostname:19be6b264b6e  Name:/docker-test1 IP:17.16.10.1286) 获取容器的log path
$ docker inspect --format='{{.LogPath}}' `docker ps -a -q`
$ docker inspect --format='{{.LogPath}}' docker-test17) 获取容器的image镜像名称
$ docker inspect --format='{{.Config.Image}}' `docker ps -a -q`
172.16.60.214:5000/nginx
172.16.60.214:5000/nginx
172.16.60.214:5000/nginx
quay.io/calico/node:v2.6.10
$ docker inspect --format='{{.Config.Image}}' docker-test1
172.16.60.214:5000/nginx8) 获取容器绑定的端口(port bindings)
$ docker inspect --format='{{range $p, $conf := .NetworkSettings.Ports}} {{$p}} -> {{(index $conf 0).HostPort}} {{end}}' `docker ps -a -q`
$ docker inspect --format='{{range $p, $conf := .NetworkSettings.Ports}} {{$p}} -> {{(index $conf 0).HostPort}} {{end}}' docker-test19) 获取service实例的Ip
$ docker service ps my-test
ID              NAME          IMAGE                         NODE                    DESIRED   STATE  CURRENT STATE    ERROR  PORTS
t71gqufekv2o  my-test.1  172.16.60.214:5000/nginx:latest  swarm-node2              Running    Running 16 seconds ago
9cuq2yf10d60 my-test.2  172.16.60.214:5000/nginx:latest  swarm-manager-node  Running   Running 16 seconds ago
srt2yo817kpv  my-test.3  172.16.60.214:5000/nginx:latest  swarm-node1               Running    Running 16 seconds ago  $ docker inspect ` docker service ps my-test -q` --format '{{range .NetworksAttachments}}{{.Addresses}}{{end}}' | cut -d '[' -f2|cut -d ']' -f1
10.255.0.7/16
10.255.0.8/16
10.255.0.9/1610) 获取service示例的container ID  (获取的是ID的全称,一般只要取ID前面12个字符就可以了)
$ docker inspect ` docker service ps my-test -q` --format '{{ .Status.ContainerStatus.ContainerID }}'
c6c18a74a465163757fe928fec9e633223200f92d1c59e5d2d77eabfaa5ae93a
5f558bb014ea3d3eef5c8d4bd70e2e3048d7fc6725538303be960ac658d93b32
dde578bf60190a63ed5c8c4a9f5a3044566a159e8debe8717342e263c6199f26

四、参考文档

1、https://blog.csdn.net/u013288190/article/details/108955218

2、https://blog.csdn.net/m0_45406092/article/details/103671832

3、https://ld246.com/article/1427784659823