Documentation
¶
Overview ¶
Package channel enables access to a channel on a Fabric network. A channel client instance provides a handler to interact with peers on specified channel. Channel client can query chaincode, execute chaincode and register/unregister for chaincode events on specific channel. An application that requires interaction with multiple channels should create a separate instance of the channel client for each channel.
Basic Flow: 1) Prepare channel client context 2) Create channel client 3) Execute chaincode 4) Query chaincode
Example ¶
c, err := New(mockChannelProvider("mychannel"))
if err != nil {
fmt.Println("failed to create client")
}
response, err := c.Query(Request{ChaincodeID: "testCC", Fcn: "invoke", Args: [][]byte{[]byte("query"), []byte("data")}})
if err != nil {
fmt.Printf("failed to query chaincode: %s\n", err)
}
fmt.Println(string(response.Payload))
Output: abc
Index ¶
- type Client
- func (cc *Client) Execute(request Request, options ...RequestOption) (Response, error)
- func (cc *Client) InvokeHandler(handler invoke.Handler, request Request, options ...RequestOption) (Response, error)
- func (cc *Client) Query(request Request, options ...RequestOption) (Response, error)
- func (cc *Client) RegisterChaincodeEvent(chainCodeID string, eventFilter string) (fab.Registration, <-chan *fab.CCEvent, error)
- func (cc *Client) UnregisterChaincodeEvent(registration fab.Registration)
- type ClientOption
- type Request
- type RequestOption
- func WithBeforeRetry(beforeRetry retry.BeforeRetryHandler) RequestOption
- func WithChaincodeFilter(ccFilter invoke.CCFilter) RequestOption
- func WithParentContext(parentContext reqContext.Context) RequestOption
- func WithRetry(retryOpt retry.Opts) RequestOption
- func WithTargetEndpoints(keys ...string) RequestOption
- func WithTargetFilter(filter fab.TargetFilter) RequestOption
- func WithTargetSorter(sorter fab.TargetSorter) RequestOption
- func WithTargets(targets ...fab.Peer) RequestOption
- func WithTimeout(timeoutType fab.TimeoutType, timeout time.Duration) RequestOption
- type Response
Examples ¶
Constants ¶
This section is empty.
Variables ¶
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Functions ¶
This section is empty.
Types ¶
type Client ¶
type Client struct {
// contains filtered or unexported fields
}
Client enables access to a channel on a Fabric network.
A channel client instance provides a handler to interact with peers on specified channel. An application that requires interaction with multiple channels should create a separate instance of the channel client for each channel. Channel client supports non-admin functions only.
func New ¶
func New(channelProvider context.ChannelProvider, opts ...ClientOption) (*Client, error)
New returns a Client instance. Channel client can query chaincode, execute chaincode and register/unregister for chaincode events on specific channel.
Example ¶
ctx := mockChannelProvider("mychannel")
c, err := New(ctx)
if err != nil {
fmt.Println(err)
}
if c != nil {
fmt.Println("channel client created")
} else {
fmt.Println("channel client is nil")
}
Output: channel client created
func (*Client) Execute ¶
func (cc *Client) Execute(request Request, options ...RequestOption) (Response, error)
Execute prepares and executes transaction using request and optional request options
Parameters: request holds info about mandatory chaincode ID and function options holds optional request options Returns: the proposal responses from peer(s)
Example ¶
c, err := New(mockChannelProvider("mychannel"))
if err != nil {
fmt.Println("failed to create client")
}
_, err = c.Execute(Request{ChaincodeID: "testCC", Fcn: "invoke", Args: [][]byte{[]byte("move"), []byte("a"), []byte("b"), []byte("1")}})
if err != nil {
fmt.Println(err.Error())
}
fmt.Println("Chaincode transaction completed")
Output: Chaincode transaction completed
func (*Client) InvokeHandler ¶
func (cc *Client) InvokeHandler(handler invoke.Handler, request Request, options ...RequestOption) (Response, error)
InvokeHandler invokes handler using request and optional request options provided
Parameters: handler to be invoked request holds info about mandatory chaincode ID and function options holds optional request options Returns: the proposal responses from peer(s)
Example ¶
c, err := New(mockChannelProvider("mychannel"))
if err != nil {
fmt.Println("failed to create client")
}
response, err := c.InvokeHandler(&exampleHandler{}, Request{ChaincodeID: "testCC", Fcn: "invoke", Args: [][]byte{[]byte("query"), []byte("data")}})
if err != nil {
fmt.Printf("failed to query chaincode: %s\n", err)
}
fmt.Println(string(response.Payload))
Output: custom
func (*Client) Query ¶
func (cc *Client) Query(request Request, options ...RequestOption) (Response, error)
Query chaincode using request and optional request options
Parameters: request holds info about mandatory chaincode ID and function options holds optional request options Returns: the proposal responses from peer(s)
Example ¶
c, err := New(mockChannelProvider("mychannel"))
if err != nil {
fmt.Println("failed to create client")
}
response, err := c.Query(Request{ChaincodeID: "testCC", Fcn: "invoke", Args: [][]byte{[]byte("query"), []byte("b")}})
if err != nil {
fmt.Printf("failed to query chaincode: %s\n", err)
}
if len(response.Payload) > 0 {
fmt.Println("chaincode query success")
}
Output: chaincode query success
func (*Client) RegisterChaincodeEvent ¶
func (cc *Client) RegisterChaincodeEvent(chainCodeID string, eventFilter string) (fab.Registration, <-chan *fab.CCEvent, error)
RegisterChaincodeEvent registers for chaincode events. Unregister must be called when the registration is no longer needed.
Parameters: chaincodeID is the chaincode ID for which events are to be received eventFilter is the chaincode event filter (regular expression) for which events are to be received Returns: the registration and a channel that is used to receive events. The channel is closed when Unregister is called.
Example ¶
c, err := New(mockChannelProvider("mychannel"))
if err != nil {
fmt.Println("failed to create client")
}
registration, _, err := c.RegisterChaincodeEvent("examplecc", "event123")
if err != nil {
fmt.Println("failed to register chaincode event")
}
defer c.UnregisterChaincodeEvent(registration)
fmt.Println("chaincode event registered successfully")
Output: chaincode event registered successfully
func (*Client) UnregisterChaincodeEvent ¶
func (cc *Client) UnregisterChaincodeEvent(registration fab.Registration)
UnregisterChaincodeEvent removes the given registration and closes the event channel.
Parameters: registration is the registration handle that was returned from RegisterChaincodeEvent method
type ClientOption ¶
ClientOption describes a functional parameter for the New constructor
type Request ¶
type Request struct {
ChaincodeID string
Fcn string
Args [][]byte
TransientMap map[string][]byte
// InvocationChain contains meta-data that's used by some Selection Service implementations
// to choose endorsers that satisfy the endorsement policies of all chaincodes involved
// in an invocation chain (i.e. for CC-to-CC invocations).
// Each chaincode may also be associated with a set of private data collection names
// which are used by some Selection Services (e.g. Fabric Selection) to exclude endorsers
// that do NOT have read access to the collections.
// The invoked chaincode (specified by ChaincodeID) may optionally be added to the invocation
// chain along with any collections, otherwise it may be omitted.
InvocationChain []*fab.ChaincodeCall
IsInit bool
}
Request contains the parameters to query and execute an invocation transaction
type RequestOption ¶
RequestOption func for each Opts argument
func WithBeforeRetry ¶
func WithBeforeRetry(beforeRetry retry.BeforeRetryHandler) RequestOption
WithBeforeRetry specifies a function to call before a retry attempt
func WithChaincodeFilter ¶
func WithChaincodeFilter(ccFilter invoke.CCFilter) RequestOption
WithChaincodeFilter adds a chaincode filter for figuring out additional endorsers
func WithParentContext ¶
func WithParentContext(parentContext reqContext.Context) RequestOption
WithParentContext encapsulates grpc parent context
func WithRetry ¶
func WithRetry(retryOpt retry.Opts) RequestOption
WithRetry option to configure retries
func WithTargetEndpoints ¶
func WithTargetEndpoints(keys ...string) RequestOption
WithTargetEndpoints allows overriding of the target peers for the request. Targets are specified by name or URL, and the SDK will create the underlying peer objects.
func WithTargetFilter ¶
func WithTargetFilter(filter fab.TargetFilter) RequestOption
WithTargetFilter specifies a per-request target peer-filter
func WithTargetSorter ¶
func WithTargetSorter(sorter fab.TargetSorter) RequestOption
WithTargetSorter specifies a per-request target sorter
func WithTargets ¶
func WithTargets(targets ...fab.Peer) RequestOption
WithTargets allows overriding of the target peers for the request
func WithTimeout ¶
func WithTimeout(timeoutType fab.TimeoutType, timeout time.Duration) RequestOption
WithTimeout encapsulates key value pairs of timeout type, timeout duration to Options
type Response ¶
type Response struct {
Proposal *fab.TransactionProposal
Responses []*fab.TransactionProposalResponse
TransactionID fab.TransactionID
TxValidationCode pb.TxValidationCode
ChaincodeStatus int32
Payload []byte
}
Response contains response parameters for query and execute an invocation transaction
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