mirror of
https://github.com/containrrr/watchtower.git
synced 2025-09-21 21:30:48 +02:00
Handle container links
Ensures that linked containers are restarted if any of their dependencies are restarted -- and makes sure that everything happens in the correct order.
This commit is contained in:
Brian DeHamer
parent
ce4ed7316c
commit
c02c4b9ec1
12 changed files with 854 additions and 183 deletions
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@ -1,112 +0,0 @@
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package updater
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import (
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"github.com/samalba/dockerclient"
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)
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// Ideally, we'd just be able to take the ContainerConfig from the old container
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// and use it as the starting point for creating the new container; however,
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// the ContainerConfig that comes back from the Inspect call merges the default
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// configuration (the stuff specified in the metadata for the image itself)
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// with the overridden configuration (the stuff that you might specify as part
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// of the "docker run"). In order to avoid unintentionally overriding the
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// defaults in the new image we need to separate the override options from the
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// default options. To do this we have to compare the ContainerConfig for the
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// running container with the ContainerConfig from the image that container was
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// started from. This function returns a ContainerConfig which contains just
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// the override options.
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func GenerateContainerConfig(oldContainerInfo *dockerclient.ContainerInfo, oldImageConfig *dockerclient.ContainerConfig) *dockerclient.ContainerConfig {
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config := oldContainerInfo.Config
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if config.WorkingDir == oldImageConfig.WorkingDir {
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config.WorkingDir = ""
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}
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if config.User == oldImageConfig.User {
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config.User = ""
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}
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if sliceEqual(config.Cmd, oldImageConfig.Cmd) {
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config.Cmd = []string{}
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}
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if sliceEqual(config.Entrypoint, oldImageConfig.Entrypoint) {
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config.Entrypoint = []string{}
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}
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config.Env = arraySubtract(config.Env, oldImageConfig.Env)
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config.Labels = stringMapSubtract(config.Labels, oldImageConfig.Labels)
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config.Volumes = structMapSubtract(config.Volumes, oldImageConfig.Volumes)
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config.ExposedPorts = structMapSubtract(config.ExposedPorts, oldImageConfig.ExposedPorts)
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for p, _ := range oldContainerInfo.HostConfig.PortBindings {
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config.ExposedPorts[p] = struct{}{}
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}
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return config
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}
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func sliceEqual(s1, s2 []string) bool {
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if len(s1) != len(s2) {
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return false
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}
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for i := range s1 {
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if s1[i] != s2[i] {
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return false
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}
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}
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return true
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}
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func stringMapSubtract(m1, m2 map[string]string) map[string]string {
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m := map[string]string{}
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for k1, v1 := range m1 {
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if v2, ok := m2[k1]; ok {
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if v2 != v1 {
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m[k1] = v1
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}
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} else {
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m[k1] = v1
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}
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}
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return m
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}
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func structMapSubtract(m1, m2 map[string]struct{}) map[string]struct{} {
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m := map[string]struct{}{}
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for k1, v1 := range m1 {
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if _, ok := m2[k1]; !ok {
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m[k1] = v1
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}
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}
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return m
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}
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func arraySubtract(a1, a2 []string) []string {
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a := []string{}
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for _, e1 := range a1 {
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found := false
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for _, e2 := range a2 {
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if e1 == e2 {
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found = true
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break
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}
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}
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if !found {
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a = append(a, e1)
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}
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}
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return a
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}
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@ -1,38 +0,0 @@
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package updater
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import (
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestStringMapSubtract(t *testing.T) {
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m1 := map[string]string{"a": "a", "b": "b", "c": "sea"}
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m2 := map[string]string{"a": "a", "c": "c"}
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result := stringMapSubtract(m1, m2)
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assert.Equal(t, map[string]string{"b": "b", "c": "sea"}, result)
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assert.Equal(t, map[string]string{"a": "a", "b": "b", "c": "sea"}, m1)
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assert.Equal(t, map[string]string{"a": "a", "c": "c"}, m2)
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}
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func TestStructMapSubtract(t *testing.T) {
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x := struct{}{}
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m1 := map[string]struct{}{"a": x, "b": x, "c": x}
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m2 := map[string]struct{}{"a": x, "c": x}
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result := structMapSubtract(m1, m2)
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assert.Equal(t, map[string]struct{}{"b": x}, result)
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assert.Equal(t, map[string]struct{}{"a": x, "b": x, "c": x}, m1)
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assert.Equal(t, map[string]struct{}{"a": x, "c": x}, m2)
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}
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func TestArraySubtract(t *testing.T) {
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a1 := []string{"a", "b", "c"}
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a2 := []string{"a", "c"}
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result := arraySubtract(a1, a2)
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assert.Equal(t, []string{"b"}, result)
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assert.Equal(t, []string{"a", "b", "c"}, a1)
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assert.Equal(t, []string{"a", "c"}, a2)
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}
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74
updater/sorter.go
Normal file
74
updater/sorter.go
Normal file
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@ -0,0 +1,74 @@
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package updater
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import (
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"fmt"
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"github.com/CenturyLinkLabs/watchtower/docker"
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)
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type ContainerSorter struct {
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unvisited []docker.Container
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marked map[string]bool
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sorted []docker.Container
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}
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func (cs *ContainerSorter) Sort(containers []docker.Container) ([]docker.Container, error) {
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cs.unvisited = containers
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cs.marked = map[string]bool{}
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for len(cs.unvisited) > 0 {
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if err := cs.visit(cs.unvisited[0]); err != nil {
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return nil, err
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}
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}
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return cs.sorted, nil
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}
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func (cs *ContainerSorter) visit(c docker.Container) error {
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if _, ok := cs.marked[c.Name()]; ok {
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return fmt.Errorf("Circular reference to %s", c.Name())
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}
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// Mark any visited node so that circular references can be detected
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cs.marked[c.Name()] = true
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defer delete(cs.marked, c.Name())
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// Recursively visit links
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for _, linkName := range c.Links() {
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if linkedContainer := cs.findUnvisited(linkName); linkedContainer != nil {
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if err := cs.visit(*linkedContainer); err != nil {
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return err
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}
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}
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}
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// Move container from unvisited to sorted
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cs.removeUnvisited(c)
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cs.sorted = append(cs.sorted, c)
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return nil
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}
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func (cs *ContainerSorter) findUnvisited(name string) *docker.Container {
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for _, c := range cs.unvisited {
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if c.Name() == name {
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return &c
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}
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}
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return nil
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}
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func (cs *ContainerSorter) removeUnvisited(c docker.Container) {
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var idx int
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for i := range cs.unvisited {
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if cs.unvisited[i].Name() == c.Name() {
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idx = i
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break
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}
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}
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cs.unvisited = append(cs.unvisited[0:idx], cs.unvisited[idx+1:]...)
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}
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37
updater/sorter_test.go
Normal file
37
updater/sorter_test.go
Normal file
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package updater
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import (
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"testing"
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"github.com/CenturyLinkLabs/watchtower/docker"
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"github.com/stretchr/testify/assert"
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)
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func TestContainerSorter_Success(t *testing.T) {
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c1 := docker.NewTestContainer("1", []string{})
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c2 := docker.NewTestContainer("2", []string{"1:"})
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c3 := docker.NewTestContainer("3", []string{"2:"})
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c4 := docker.NewTestContainer("4", []string{"3:"})
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c5 := docker.NewTestContainer("5", []string{"4:"})
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c6 := docker.NewTestContainer("6", []string{"5:", "3:"})
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containers := []docker.Container{c6, c2, c4, c1, c3, c5}
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cs := ContainerSorter{}
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result, err := cs.Sort(containers)
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assert.NoError(t, err)
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assert.Equal(t, []docker.Container{c1, c2, c3, c4, c5, c6}, result)
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}
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func TestContainerSorter_Error(t *testing.T) {
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c1 := docker.NewTestContainer("1", []string{"3:"})
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c2 := docker.NewTestContainer("2", []string{"1:"})
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c3 := docker.NewTestContainer("3", []string{"2:"})
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containers := []docker.Container{c1, c2, c3}
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cs := ContainerSorter{}
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_, err := cs.Sort(containers)
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assert.Error(t, err)
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assert.EqualError(t, err, "Circular reference to 1")
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}
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@ -1,81 +1,71 @@
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package updater
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import (
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"log"
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"github.com/samalba/dockerclient"
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"github.com/CenturyLinkLabs/watchtower/docker"
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)
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var (
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client dockerclient.Client
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)
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func init() {
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docker, err := dockerclient.NewDockerClient("unix:///var/run/docker.sock", nil)
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if err != nil {
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log.Fatalf("Error instantiating Docker client: %s\n", err)
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}
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client = docker
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}
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func Run() error {
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containers, _ := client.ListContainers(false, false, "")
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client := docker.NewClient()
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containers, err := client.ListContainers()
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if err != nil {
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return err
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}
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for _, container := range containers {
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oldContainerInfo, _ := client.InspectContainer(container.Id)
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name := oldContainerInfo.Name
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oldImageId := oldContainerInfo.Image
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log.Printf("Running: %s (%s)\n", container.Image, oldImageId)
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oldImageInfo, _ := client.InspectImage(oldImageId)
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// First check to see if a newer image has already been built
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newImageInfo, _ := client.InspectImage(container.Image)
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if newImageInfo.Id == oldImageInfo.Id {
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_ = client.PullImage(container.Image, nil)
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newImageInfo, _ = client.InspectImage(container.Image)
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for i := range containers {
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if err := client.RefreshImage(&containers[i]); err != nil {
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return err
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}
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}
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newImageId := newImageInfo.Id
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log.Printf("Latest: %s (%s)\n", container.Image, newImageId)
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containers, err = sortContainers(containers)
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if err != nil {
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return err
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}
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if newImageId != oldImageId {
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log.Printf("Restarting %s with new image\n", name)
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if err := stopContainer(oldContainerInfo); err != nil {
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checkDependencies(containers)
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// Stop stale containers in reverse order
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for i := len(containers) - 1; i >= 0; i-- {
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container := containers[i]
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if container.Stale {
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if err := client.Stop(container); err != nil {
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return err
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}
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}
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}
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config := GenerateContainerConfig(oldContainerInfo, oldImageInfo.Config)
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hostConfig := oldContainerInfo.HostConfig
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_ = startContainer(name, config, hostConfig)
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// Restart stale containers in sorted order
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for _, container := range containers {
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if container.Stale {
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if err := client.Start(container); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func stopContainer(container *dockerclient.ContainerInfo) error {
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signal := "SIGTERM"
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if sig, ok := container.Config.Labels["com.centurylinklabs.watchtower.stop-signal"]; ok {
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signal = sig
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}
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if err := client.KillContainer(container.Id, signal); err != nil {
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return err
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}
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return client.RemoveContainer(container.Id, true, false)
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func sortContainers(containers []docker.Container) ([]docker.Container, error) {
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sorter := ContainerSorter{}
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return sorter.Sort(containers)
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}
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func startContainer(name string, config *dockerclient.ContainerConfig, hostConfig *dockerclient.HostConfig) error {
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newContainerId, err := client.CreateContainer(config, name)
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if err != nil {
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return err
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}
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func checkDependencies(containers []docker.Container) {
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return client.StartContainer(newContainerId, hostConfig)
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for i, parent := range containers {
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if parent.Stale {
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continue
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}
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LinkLoop:
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for _, linkName := range parent.Links() {
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for _, child := range containers {
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if child.Name() == linkName && child.Stale {
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containers[i].Stale = true
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break LinkLoop
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}
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}
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}
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}
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}
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29
updater/updater_test.go
Normal file
29
updater/updater_test.go
Normal file
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@ -0,0 +1,29 @@
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package updater
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import (
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"testing"
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"github.com/CenturyLinkLabs/watchtower/docker"
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"github.com/stretchr/testify/assert"
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)
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func TestCheckDependencies(t *testing.T) {
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cs := []docker.Container{
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docker.NewTestContainer("1", []string{}),
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docker.NewTestContainer("2", []string{"1:"}),
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docker.NewTestContainer("3", []string{"2:"}),
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docker.NewTestContainer("4", []string{"3:"}),
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docker.NewTestContainer("5", []string{"4:"}),
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docker.NewTestContainer("6", []string{"5:"}),
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}
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cs[3].Stale = true
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checkDependencies(cs)
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assert.False(t, cs[0].Stale)
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assert.False(t, cs[1].Stale)
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assert.False(t, cs[2].Stale)
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assert.True(t, cs[3].Stale)
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assert.True(t, cs[4].Stale)
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assert.True(t, cs[5].Stale)
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}
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