README
¶
dag
-- import "github.com/qri-io/dag"
Package dag is the base of a family of packages for working with directed acyclic graphs (DAGs) most (if not all) use cases assume the dag is a merkle-tree https://en.wikipedia.org/wiki/Merkle_tree
Usage
type Completion
type Completion []uint16
Completion tracks the presence of blocks described in a manifest Completion can be used to store transfer progress, or be stored as a record of which blocks in a DAG are missing each element in the slice represents the index a block in a manifest.Nodes field, which contains the hash of a block needed to complete a manifest the element in the progress slice represents the transmission completion of that block locally. It must be a number from 0-100, 0 = nothing locally, 100 = block is local. note that progress is not necessarily linear. for example the following is 50% complete progress:
manifest.Nodes: ["QmA", "QmB", "QmC", "QmD"] progress: [0, 100, 0, 100]
func NewCompletion
func NewCompletion(mfst, missing *Manifest) Completion
NewCompletion constructs a progress from
func (Completion) Complete
func (p Completion) Complete() bool
Complete returns weather progress is finished
func (Completion) CompletedBlocks
func (p Completion) CompletedBlocks() (count int)
CompletedBlocks returns the number of blocks that are completed
func (Completion) Percentage
func (p Completion) Percentage() (pct float32)
Percentage expressess the completion as a floating point number betwen 0.0 and 1.0
type Info
type Info struct {
// Info is built upon a manifest
Manifest *Manifest `json:"manifest"`
Paths map[string]int `json:"paths,omitempty"` // sections are lists of logical sub-DAGs by positions in the nodes list
Sizes []uint64 `json:"sizes,omitempty"` // sizes of nodes in bytes
}
Info is os.FileInfo for dags: a struct that describes important details about a graph. Info builds on a manifest
when being sent over the network, the contents of Info should be considered gossip, as Info's are not deterministic. This has important implications Info should contain application-specific info about a datset
func NewInfo
func NewInfo(ctx context.Context, ng ipld.NodeGetter, id cid.Cid) (*Info, error)
NewInfo creates a
type Manifest
type Manifest struct {
Links [][2]int `json:"links"` // links between nodes
Nodes []string `json:"nodes"` // list if CIDS contained in the DAG
}
Manifest is a determinsitc description of a complete directed acyclic graph. Analogous to bittorrent .magnet files, manifests contain no content, only a description of the structure of a graph (nodes and links)
Manifests are built around a flat list of node identifiers (usually hashes) and a list of links. A link element is a tuple of [from,to] where from and to are indexes in the nodes list
Manifests always describe the FULL graph, a root node and all it's descendants
A valid manifest has the following properties: * supplying the same dag to the manifest function must be deterministic:
manifest_of_dag = manifest(dag)
hash(manifest_of_dag) == hash(manifest(dag))
-
In order to generate a manifest, you need the full DAG * The list of nodes MUST be sorted by number of descendants. When two nodes
have the same number of descenants, they MUST be sorted lexographically by node ID. The means the root of the DAG will always be the first index
Manifests are intentionally limited in scope to make them easier to prove, faster to calculate, hard requirement the list of nodes can be used as a base other structures can be built upon. by keeping manifests at a minimum they are easier to verify, forming a foundation for
func Missing
func Missing(ctx context.Context, ng ipld.NodeGetter, m *Manifest) (missing *Manifest, err error)
Missing returns a manifest describing blocks that are not in this node for a given manifest
func NewManifest
func NewManifest(ctx context.Context, ng ipld.NodeGetter, id cid.Cid) (*Manifest, error)
NewManifest generates a manifest from an ipld node
func UnmarshalCBORManifest
func UnmarshalCBORManifest(data []byte) (m *Manifest, err error)
UnmarshalCBORManifest decodes a manifest from a byte slice
func (*Manifest) MarshalCBOR
func (m *Manifest) MarshalCBOR() (data []byte, err error)
MarshalCBOR encodes this manifest as CBOR data
type Node
type Node interface {
// pulled from blocks.Block format
Cid() cid.Cid
// Links is a helper function that returns all links within this object
Links() []*ipld.Link
// Size returns the size in bytes of the serialized object
Size() (uint64, error)
}
Node is a subset of the ipld ipld.Node interface, defining just the necessary bits the dag package works with
type NodeGetter
type NodeGetter struct {
Dag coreiface.DagAPI
}
NodeGetter wraps the go-ipfs DagAPI to satistfy the IPLD NodeGetter interface
func (*NodeGetter) Get
func (ng *NodeGetter) Get(ctx context.Context, id cid.Cid) (ipld.Node, error)
Get retrieves nodes by CID. Depending on the NodeGetter implementation, this may involve fetching the Node from a remote machine; consider setting a deadline in the context.
func (*NodeGetter) GetMany
func (ng *NodeGetter) GetMany(ctx context.Context, cids []cid.Cid) <-chan *ipld.NodeOption
GetMany returns a channel of NodeOptions given a set of CIDs.
Documentation
¶
Overview ¶
Package dag is the base of a family of packages for working with directed acyclic graphs (DAGs) most (if not all) use cases assume the dag is a merkle-tree https://en.wikipedia.org/wiki/Merkle_tree
dag package has two external dependencies that are worth developing an understanding of:
- cid - github.com/ipfs/go-cid, github.com/ipld/specs "Content IDentifiers" is a hashing technique that embeds additional info about the hash in question
- ipld - github.com/ipfs/go-ipld-format, github.com/ipld/specs ipld is a linked-data format for content-addressed data
def check those out. dag package attempts to interoperate with these interfaces wherever & whenever possible, in the name of compatibility
Index ¶
- Variables
- type Completion
- type Info
- func (i *Info) AddLabel(label string, index int) error
- func (i *Info) AddLabelByID(label, id string) error
- func (i *Info) InfoAtID(id string) (*Info, error)
- func (i *Info) InfoAtIndex(idx int) (*Info, error)
- func (i *Info) InfoAtLabel(label string) (*Info, error)
- func (i *Info) MarshalCBOR() (data []byte, err error)
- func (i *Info) RootCID() cid.Cid
- type InfoStore
- type Manifest
- type MemInfoStore
- type Node
- type NodeGetter
Constants ¶
This section is empty.
Variables ¶
var ( // ErrIndexOutOfRange indicates the index given is out of range of the Manifest ErrIndexOutOfRange = fmt.Errorf("index out of range") // ErrIDNotFound indicates the id given is not found in the Manifest ErrIDNotFound = fmt.Errorf("id not found in Manifest") )
var ErrInfoNotFound = fmt.Errorf("Info: not found")
ErrInfoNotFound should be returned by all implementations of DAGInfoStore when a DAG isn't found
Functions ¶
This section is empty.
Types ¶
type Completion ¶
type Completion []uint16
Completion tracks the presence of blocks described in a manifest Completion can be used to store transfer progress, or be stored as a record of which blocks in a DAG are missing each element in the slice represents the index a block in a manifest.Nodes field, which contains the hash of a block needed to complete a manifest the element in the progress slice represents the transmission completion of that block locally. It must be a number from 0-100, 0 = nothing locally, 100 = block is local. note that progress is not necessarily linear. for example the following is 50% complete progress:
manifest.Nodes: ["QmA", "QmB", "QmC", "QmD"] progress: [0, 100, 0, 100]
func NewCompletion ¶
func NewCompletion(mfst, missing *Manifest) Completion
NewCompletion constructs a progress from
func (Completion) Complete ¶
func (p Completion) Complete() bool
Complete returns weather progress is finished
func (Completion) CompletedBlocks ¶
func (p Completion) CompletedBlocks() (count int)
CompletedBlocks returns the number of blocks that are completed
func (Completion) Percentage ¶
func (p Completion) Percentage() (pct float32)
Percentage expressess the completion as a floating point number betwen 0.0 and 1.0
type Info ¶
type Info struct {
// Info is built upon a manifest
Manifest *Manifest `json:"manifest"`
Labels map[string]int `json:"labels,omitempty"` // sections are lists of logical sub-DAGs by positions in the nodes list
Sizes []uint64 `json:"sizes,omitempty"` // sizes of nodes in bytes
}
Info is os.FileInfo for dags: a struct that describes important details about a graph. Info builds on a manifest.
when being sent over the network, the contents of Info should be considered gossip, as Info's are *not* deterministic. This has important implications Info should contain application-specific info about a datset
func UnmarshalCBORDagInfo ¶ added in v0.2.0
UnmarshalCBORDagInfo decodes an Info from a byte slice
func (*Info) AddLabel ¶
AddLabel adds a label to the list of Info.Labels it returns an error if the index is out of bounds
func (*Info) AddLabelByID ¶
AddLabelByID adds a label to the list of Info.Labels it returns an error if the id is not part of the DAG
func (*Info) InfoAtID ¶
InfoAtID returns a sub-Info, the DAG, sizes, and labels, with the given id as root of the DAG
func (*Info) InfoAtIndex ¶
InfoAtIndex returns a sub-Info, the DAG, sizes, and labels, with the given index as root of the DAG
func (*Info) InfoAtLabel ¶
InfoAtLabel returns a sub-Info, the DAG, sizes, and labels, with the given label as root of the DAG
func (*Info) MarshalCBOR ¶ added in v0.2.0
MarshalCBOR encodes a dag.Info as CBOR data
type InfoStore ¶
type InfoStore interface {
// store an Info struct at the key, overwriting any previous entry.
// The most Common way to use this is keying by the RootCID. eg:
// store.PutDAGInfo(ctx, di.RootCID().String(), di)
// implementations must support arbitrary keys
PutDAGInfo(ctx context.Context, key string, di *Info) error
// get dag information stored at key, return ErrInfoNotFound when
// a key isn't present in the store
DAGInfo(ctx context.Context, key string) (di *Info, err error)
// Remove an info stored at key. Deletes for keys that don't exist should not
// return an error, deleted returns true if a value was present before the call
DeleteDAGInfo(ctx context.Context, key string) (deleted bool, err error)
}
InfoStore is the interface for a key-value store DAG information, keyed by id strings by convention the id stored should match the root id of the DAG being described
func NewMemInfoStore ¶
func NewMemInfoStore() InfoStore
NewMemInfoStore creates an in-memory InfoStore
type Manifest ¶
type Manifest struct {
Links [][2]int `json:"links"` // links between nodes
Nodes []string `json:"nodes"` // list if CIDS contained in the DAG
}
Manifest is a determinsitc description of a complete directed acyclic graph. Analogous to bittorrent .magnet files, manifests contain no content, only a description of the structure of a graph (nodes and links)
Manifests are built around a flat list of node identifiers (usually hashes) and a list of links. A link element is a tuple of [from,to] where from and to are indexes in the nodes list
Manifests always describe the FULL graph, a root node and all it's descendants ¶
A valid manifest has the following properties:
- supplying the same dag to the manifest function must be deterministic: manifest_of_dag = manifest(dag) hash(manifest_of_dag) == hash(manifest(dag))
- In order to generate a manifest, you need the full DAG
- The list of nodes MUST be sorted by number of descendants. When two nodes have the same number of descenants, they MUST be sorted lexographically by node ID. The means the root of the DAG will always be the first index
Manifests are intentionally limited in scope to make them easier to prove, faster to calculate, hard requirement the list of nodes can be used as a base other structures can be built upon. by keeping manifests at a minimum they are easier to verify, forming a foundation for
func Missing ¶
Missing returns a manifest describing blocks that are not in this node for a given manifest
func NewManifest ¶
NewManifest generates a manifest from an ipld node
func UnmarshalCBORManifest ¶
UnmarshalCBORManifest decodes a manifest from a byte slice
func (*Manifest) MarshalCBOR ¶
MarshalCBOR encodes this manifest as CBOR data
type MemInfoStore ¶
type MemInfoStore struct {
// contains filtered or unexported fields
}
MemInfoStore is an implementation of InfoStore that uses an in-memory map
func (*MemInfoStore) DAGInfo ¶
DAGInfo gets dag information stored at key, return ErrInfoNotFound when a key isn't present in the store
func (*MemInfoStore) DeleteDAGInfo ¶
DeleteDAGInfo removes the info at key from the store
func (*MemInfoStore) PutDAGInfo ¶
PutDAGInfo stores an Info struct at the key id, overwriting any previous entry
type Node ¶
type Node interface {
// pulled from blocks.Block format
Cid() cid.Cid
// Links is a helper function that returns all links within this object
Links() []*ipld.Link
// Size returns the size in bytes of the serialized object
Size() (uint64, error)
}
Node is a subset of the ipld ipld.Node interface, defining just the necessary bits the dag package works with
type NodeGetter ¶
type NodeGetter struct {
Dag ipld.DAGService
}
NodeGetter wraps the go-ipfs DagAPI to satistfy the IPLD NodeGetter interface
func NewNodeGetter ¶
func NewNodeGetter(dsvc ipld.DAGService) *NodeGetter
NewNodeGetter returns a new NodeGetter from an IPFS core API
func (*NodeGetter) Get ¶
Get retrieves nodes by CID. Depending on the NodeGetter implementation, this may involve fetching the Node from a remote machine; consider setting a deadline in the context.
func (*NodeGetter) GetMany ¶
func (ng *NodeGetter) GetMany(ctx context.Context, cids []cid.Cid) <-chan *ipld.NodeOption
GetMany returns a channel of NodeOptions given a set of CIDs.
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
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Package dsync implements point-to-point merkle-DAG-syncing between a local instance and remote source.
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Package dsync implements point-to-point merkle-DAG-syncing between a local instance and remote source. |
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dsync_ipfs_plugin
DsyncPlugin is an ipfs deamon plugin for embedding dsync functionality directly into IPFS https://github.com/ipfs/go-ipfs-example-plugin
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DsyncPlugin is an ipfs deamon plugin for embedding dsync functionality directly into IPFS https://github.com/ipfs/go-ipfs-example-plugin |