package libpod import "github.com/containers/libpod/libpod/config" // State is a storage backend for libpod's current state. // A State is only initialized once per instance of libpod. // As such, initialization methods for State implementations may safely assume // they will be run as a singleton. // For all container and pod retrieval methods, a State must retrieve the // Configuration struct of the container or pod and include it in the returned // struct. The State of the container or pod may optionally be included as well, // but this is not a requirement. // As such, all containers and pods must be synced with the database via the // UpdateContainer and UpdatePod calls before any state-specific information is // retrieved after they are pulled from the database. // Generally speaking, the syncContainer() call should be run at the beginning // of all API operations, which will silently handle this. type State interface { // Close performs any pre-exit cleanup (e.g. closing database // connections) that may be required Close() error // Refresh clears container and pod states after a reboot Refresh() error // GetDBConfig retrieves several paths configured within the database // when it was created - namely, Libpod root and tmp dirs, c/storage // root and tmp dirs, and c/storage graph driver. // This is not implemented by the in-memory state, as it has no need to // validate runtime configuration. GetDBConfig() (*config.DBConfig, error) // ValidateDBConfig validates the config in the given Runtime struct // against paths stored in the configured database. // Libpod root and tmp dirs and c/storage root and tmp dirs and graph // driver are validated. // This is not implemented by the in-memory state, as it has no need to // validate runtime configuration that may change over multiple runs of // the program. ValidateDBConfig(runtime *Runtime) error // SetNamespace() sets the namespace for the store, and will determine // what containers are retrieved with container and pod retrieval calls. // A namespace of "", the empty string, acts as no namespace, and // containers and pods in all namespaces will be returned. SetNamespace(ns string) error // Return a container from the database from its full ID. // If the container is not in the set namespace, an error will be // returned. Container(id string) (*Container, error) // Return a container ID from the database by full or partial ID or full // name. LookupContainerID(idOrName string) (string, error) // Return a container from the database by full or partial ID or full // name. // Containers not in the set namespace will be ignored. LookupContainer(idOrName string) (*Container, error) // Check if a container with the given full ID exists in the database. // If the container exists but is not in the set namespace, false will // be returned. HasContainer(id string) (bool, error) // Adds container to state. // The container cannot be part of a pod. // The container must have globally unique name and ID - pod names and // IDs also conflict with container names and IDs. // The container must be in the set namespace if a namespace has been // set. // All containers this container depends on must be part of the same // namespace and must not be joined to a pod. AddContainer(ctr *Container) error // Removes container from state. // Containers that are part of pods must use RemoveContainerFromPod. // The container must be part of the set namespace. // All dependencies must be removed first. // All exec sessions referencing the container must be removed first. RemoveContainer(ctr *Container) error // UpdateContainer updates a container's state from the backing store. // The container must be part of the set namespace. UpdateContainer(ctr *Container) error // SaveContainer saves a container's current state to the backing store. // The container must be part of the set namespace. SaveContainer(ctr *Container) error // ContainerInUse checks if other containers depend upon a given // container. // It returns a slice of the IDs of containers which depend on the given // container. If the slice is empty, no container depend on the given // container. // A container cannot be removed if other containers depend on it. // The container being checked must be part of the set namespace. ContainerInUse(ctr *Container) ([]string, error) // Retrieves all containers presently in state. // If a namespace is set, only containers within the namespace will be // returned. AllContainers() ([]*Container, error) // Return a container config from the database by full ID GetContainerConfig(id string) (*ContainerConfig, error) // Add creates a reference to an exec session in the database. // The container the exec session is attached to will be recorded. // The container state will not be modified. // The actual exec session itself is part of the container's state. // We assume higher-level callers will add the session by saving the // container's state before calling this. This only ensures that the ID // of the exec session is associated with the ID of the container. // Implementations may, but are not required to, verify that the state // of the given container has an exec session with the ID given. AddExecSession(ctr *Container, session *ExecSession) error // Get retrieves the container a given exec session is attached to. GetExecSession(id string) (string, error) // Remove a reference to an exec session from the database. // This will not modify container state to remove the exec session there // and instead only removes the session ID -> container ID reference // added by AddExecSession. RemoveExecSession(session *ExecSession) error // Get the IDs of all exec sessions attached to a given container. GetContainerExecSessions(ctr *Container) ([]string, error) // Remove all exec sessions for a single container. // Usually used as part of removing the container. // As with RemoveExecSession, container state will not be modified. RemoveContainerExecSessions(ctr *Container) error // PLEASE READ FULL DESCRIPTION BEFORE USING. // Rewrite a container's configuration. // This function breaks libpod's normal prohibition on a read-only // configuration, and as such should be used EXTREMELY SPARINGLY and // only in very specific circumstances. // Specifically, it is ONLY safe to use thing function to make changes // that result in a functionally identical configuration (migrating to // newer, but identical, configuration fields), or during libpod init // WHILE HOLDING THE ALIVE LOCK (to prevent other libpod instances from // being initialized). // Most things in config can be changed by this, but container ID and // name ABSOLUTELY CANNOT BE ALTERED. If you do so, there is a high // potential for database corruption. // There are a lot of capital letters and conditions here, but the short // answer is this: use this only very sparingly, and only if you really // know what you're doing. RewriteContainerConfig(ctr *Container, newCfg *ContainerConfig) error // PLEASE READ THE DESCRIPTION FOR RewriteContainerConfig BEFORE USING. // This function is identical to RewriteContainerConfig, save for the // fact that it is used with pods instead. // It is subject to the same conditions as RewriteContainerConfig. // Please do not use this unless you know what you're doing. RewritePodConfig(pod *Pod, newCfg *PodConfig) error // PLEASE READ THE DESCRIPTION FOR RewriteContainerConfig BEFORE USING. // This function is identical to RewriteContainerConfig, save for the // fact that it is used with volumes instead. // It is subject to the same conditions as RewriteContainerConfig. // The exception is that volumes do not have IDs, so only volume name // cannot be altered. // Please do not use this unless you know what you're doing. RewriteVolumeConfig(volume *Volume, newCfg *VolumeConfig) error // Accepts full ID of pod. // If the pod given is not in the set namespace, an error will be // returned. Pod(id string) (*Pod, error) // Accepts full or partial IDs (as long as they are unique) and names. // Pods not in the set namespace are ignored. LookupPod(idOrName string) (*Pod, error) // Checks if a pod with the given ID is present in the state. // If the given pod is not in the set namespace, false is returned. HasPod(id string) (bool, error) // Check if a pod has a container with the given ID. // The pod must be part of the set namespace. PodHasContainer(pod *Pod, ctrID string) (bool, error) // Get the IDs of all containers in a pod. // The pod must be part of the set namespace. PodContainersByID(pod *Pod) ([]string, error) // Get all the containers in a pod. // The pod must be part of the set namespace. PodContainers(pod *Pod) ([]*Container, error) // Adds pod to state. // The pod must be part of the set namespace. // The pod's name and ID must be globally unique. AddPod(pod *Pod) error // Removes pod from state. // Only empty pods can be removed from the state. // The pod must be part of the set namespace. RemovePod(pod *Pod) error // Remove all containers from a pod. // Used to simultaneously remove containers that might otherwise have // dependency issues. // Will fail if a dependency outside the pod is encountered. // The pod must be part of the set namespace. RemovePodContainers(pod *Pod) error // AddContainerToPod adds a container to an existing pod. // The container given will be added to the state and the pod. // The container and its dependencies must be part of the given pod, // and the given pod's namespace. // The pod must be part of the set namespace. // The pod must already exist in the state. // The container's name and ID must be globally unique. AddContainerToPod(pod *Pod, ctr *Container) error // RemoveContainerFromPod removes a container from an existing pod. // The container will also be removed from the state. // The container must be in the given pod, and the pod must be in the // set namespace. RemoveContainerFromPod(pod *Pod, ctr *Container) error // UpdatePod updates a pod's state from the database. // The pod must be in the set namespace. UpdatePod(pod *Pod) error // SavePod saves a pod's state to the database. // The pod must be in the set namespace. SavePod(pod *Pod) error // Retrieves all pods presently in state. // If a namespace has been set, only pods in that namespace will be // returned. AllPods() ([]*Pod, error) // Volume accepts full name of volume // If the volume doesn't exist, an error will be returned Volume(volName string) (*Volume, error) // LookupVolume accepts an unambiguous partial name or full name of a // volume. Ambiguous names will result in an error. LookupVolume(name string) (*Volume, error) // HasVolume returns true if volName exists in the state, // otherwise it returns false HasVolume(volName string) (bool, error) // VolumeInUse goes through the container dependencies of a volume // and checks if the volume is being used by any container. If it is // a slice of container IDs using the volume is returned VolumeInUse(volume *Volume) ([]string, error) // AddVolume adds the specified volume to state. The volume's name // must be unique within the list of existing volumes AddVolume(volume *Volume) error // RemoveVolume removes the specified volume. // Only volumes that have no container dependencies can be removed RemoveVolume(volume *Volume) error // UpdateVolume updates the volume's state from the database. UpdateVolume(volume *Volume) error // SaveVolume saves a volume's state to the database. SaveVolume(volume *Volume) error // AllVolumes returns all the volumes available in the state AllVolumes() ([]*Volume, error) }