Add backend code for generic dependencies

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #577
Approved by: rhatdan

libpod/container.go

@@ -205,6 +205,8 @@ type ContainerConfig struct {
 	// Namespace Config
 	// IDs of container to share namespaces with
 	// NetNsCtr conflicts with the CreateNetNS bool
+	// These containers are considered dependencies of the given container
+	// They must be started before the given container is started
 	IPCNsCtr    string `json:"ipcNsCtr,omitempty"`
 	MountNsCtr  string `json:"mountNsCtr,omitempty"`
 	NetNsCtr    string `json:"netNsCtr,omitempty"`
@@ -213,6 +215,10 @@ type ContainerConfig struct {
 	UTSNsCtr    string `json:"utsNsCtr,omitempty"`
 	CgroupNsCtr string `json:"cgroupNsCtr,omitempty"`
 
+	// IDs of dependency containers
+	// These containers must be started before this container is started
+	Dependencies []string
+
 	// Network Config
 	// CreateNetNS indicates that libpod should create and configure a new
 	// network namespace for the container
@@ -363,6 +369,8 @@ func (c *Container) User() string {
 func (c *Container) Dependencies() []string {
 	// Collect in a map first to remove dupes
 	dependsCtrs := map[string]bool{}
+
+	// First add all namespace containers
 	if c.config.IPCNsCtr != "" {
 		dependsCtrs[c.config.IPCNsCtr] = true
 	}
@@ -385,6 +393,11 @@ func (c *Container) Dependencies() []string {
 		dependsCtrs[c.config.CgroupNsCtr] = true
 	}
 
+	// Add all generic dependencies
+	for _, id := range c.config.Dependencies {
+		dependsCtrs[id] = true
+	}
+
 	if len(dependsCtrs) == 0 {
 		return []string{}
 	}

libpod/options.go

@@ -625,6 +625,38 @@ func WithCgroupNSFrom(nsCtr *Container) CtrCreateOption {
 	}
 }
 
+// WithDependencies sets dependency containers of the given container
+// Dependency containers must be running before this container is started
+func WithDependencyCtrs(ctrs []*Container) CtrCreateOption {
+	return func(ctr *Container) error {
+		if ctr.valid {
+			return ErrCtrFinalized
+		}
+
+		deps := make([]string, 0, len(ctrs))
+
+		for _, dep := range ctrs {
+			if !dep.valid {
+				return errors.Wrapf(ErrCtrRemoved, "container %s is not valid", dep.ID())
+			}
+
+			if dep.ID() == ctr.ID() {
+				return errors.Wrapf(ErrInvalidArg, "must specify another container")
+			}
+
+			if ctr.config.Pod != "" && dep.config.Pod != ctr.config.Pod {
+				return errors.Wrapf(ErrInvalidArg, "container has joined pod %s and dependency container %s is not a member of the pod", ctr.config.Pod, dep.ID())
+			}
+
+			deps = append(deps, dep.ID())
+		}
+
+		ctr.config.Dependencies = deps
+
+		return nil
+	}
+}
+
 // WithNetNS indicates that the container should be given a new network
 // namespace with a minimal configuration
 // An optional array of port mappings can be provided

libpod/state_test.go

@@ -656,6 +656,83 @@ func TestContainerInUseOneContainerMultipleDependencies(t *testing.T) {
 	})
 }
 
+func TestContainerInUseGenericDependency(t *testing.T) {
+	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
+		testCtr1, err := getTestCtr1(lockPath)
+		assert.NoError(t, err)
+		testCtr2, err := getTestCtr2(lockPath)
+		assert.NoError(t, err)
+
+		testCtr2.config.Dependencies = []string{testCtr1.config.ID}
+
+		err = state.AddContainer(testCtr1)
+		assert.NoError(t, err)
+
+		err = state.AddContainer(testCtr2)
+		assert.NoError(t, err)
+
+		ids, err := state.ContainerInUse(testCtr1)
+		assert.NoError(t, err)
+		assert.Equal(t, 1, len(ids))
+		assert.Equal(t, testCtr2.config.ID, ids[0])
+	})
+}
+
+func TestContainerInUseMultipleGenericDependencies(t *testing.T) {
+	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
+		testCtr1, err := getTestCtr1(lockPath)
+		assert.NoError(t, err)
+		testCtr2, err := getTestCtr2(lockPath)
+		assert.NoError(t, err)
+		testCtr3, err := getTestCtrN("3", lockPath)
+		assert.NoError(t, err)
+
+		testCtr3.config.Dependencies = []string{testCtr1.config.ID, testCtr2.config.ID}
+
+		err = state.AddContainer(testCtr1)
+		assert.NoError(t, err)
+
+		err = state.AddContainer(testCtr2)
+		assert.NoError(t, err)
+
+		err = state.AddContainer(testCtr3)
+		assert.NoError(t, err)
+
+		ids1, err := state.ContainerInUse(testCtr1)
+		assert.NoError(t, err)
+		assert.Equal(t, 1, len(ids1))
+		assert.Equal(t, testCtr3.config.ID, ids1[0])
+
+		ids2, err := state.ContainerInUse(testCtr2)
+		assert.NoError(t, err)
+		assert.Equal(t, 1, len(ids2))
+		assert.Equal(t, testCtr3.config.ID, ids2[0])
+	})
+}
+
+func TestContainerInUseGenericAndNamespaceDependencies(t *testing.T) {
+	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
+		testCtr1, err := getTestCtr1(lockPath)
+		assert.NoError(t, err)
+		testCtr2, err := getTestCtr2(lockPath)
+		assert.NoError(t, err)
+
+		testCtr2.config.Dependencies = []string{testCtr1.config.ID}
+		testCtr2.config.IPCNsCtr = testCtr1.config.ID
+
+		err = state.AddContainer(testCtr1)
+		assert.NoError(t, err)
+
+		err = state.AddContainer(testCtr2)
+		assert.NoError(t, err)
+
+		ids, err := state.ContainerInUse(testCtr1)
+		assert.NoError(t, err)
+		assert.Equal(t, 1, len(ids))
+		assert.Equal(t, testCtr2.config.ID, ids[0])
+	})
+}
+
 func TestCannotRemoveContainerWithDependency(t *testing.T) {
 	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
 		testCtr1, err := getTestCtr1(lockPath)
@@ -680,6 +757,30 @@ func TestCannotRemoveContainerWithDependency(t *testing.T) {
 	})
 }
 
+func TestCannotRemoveContainerWithGenericDependency(t *testing.T) {
+	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
+		testCtr1, err := getTestCtr1(lockPath)
+		assert.NoError(t, err)
+		testCtr2, err := getTestCtr2(lockPath)
+		assert.NoError(t, err)
+
+		testCtr2.config.Dependencies = []string{testCtr1.config.ID}
+
+		err = state.AddContainer(testCtr1)
+		assert.NoError(t, err)
+
+		err = state.AddContainer(testCtr2)
+		assert.NoError(t, err)
+
+		err = state.RemoveContainer(testCtr1)
+		assert.Error(t, err)
+
+		ctrs, err := state.AllContainers()
+		assert.NoError(t, err)
+		assert.Equal(t, 2, len(ctrs))
+	})
+}
+
 func TestCanRemoveContainerAfterDependencyRemoved(t *testing.T) {
 	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
 		testCtr1, err := getTestCtr1(lockPath)
@@ -773,6 +874,22 @@ func TestCannotUseBadIDAsDependency(t *testing.T) {
 	})
 }
 
+func TestCannotUseBadIDAsGenericDependency(t *testing.T) {
+	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
+		testCtr, err := getTestCtr1(lockPath)
+		assert.NoError(t, err)
+
+		testCtr.config.Dependencies = []string{strings.Repeat("5", 32)}
+
+		err = state.AddContainer(testCtr)
+		assert.Error(t, err)
+
+		ctrs, err := state.AllContainers()
+		assert.NoError(t, err)
+		assert.Equal(t, 0, len(ctrs))
+	})
+}
+
 func TestGetPodDoesNotExist(t *testing.T) {
 	runForAllStates(t, func(t *testing.T, state State, lockPath string) {
 		_, err := state.Pod("doesnotexist")