mirror of
https://github.com/hyperledger/fabric-samples.git
synced 2026-06-18 16:05:10 +00:00
f6858cc7e1
- switch to ClientConnInterface - use command type alias for map of commands - add error return to command functions and handle in app.go - inline formatJSON function in getAllAssets.go - replace most panics with error returns - remove error wrapping in listen.go and further down the line - use strconv.ParseUint instead of ParseFloat - use WithCancelCause in transact.go to grab and propagate error from go routine - unmarshal and return []Asset in atb.GetAllAssets - switch to rand package - remove dependency to protobuf reflect package - switch to sync.OnceValues for caching parser - fixed typo in events sample connect.go Signed-off-by: Stanislav Jakuschevskij <stas@two-giants.com>
93 lines
2.3 KiB
Go
93 lines
2.3 KiB
Go
package main
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import (
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"encoding/json"
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"errors"
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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var storeFile = envOrDefault("STORE_FILE", "store.log")
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var simulatedFailureCount = getSimulatedFailureCount()
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var transactionCount uint = 0 // Used only to simulate failures
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// Apply writes for a given transaction to off-chain data store, ideally in a single operation for fault tolerance.
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type writer = func(data ledgerUpdate) error
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// Ledger update made by a specific transaction.
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type ledgerUpdate struct {
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BlockNumber uint64
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TransactionID string
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Writes []write
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}
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// Description of a ledger Write that can be applied to an off-chain data store.
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type write struct {
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// Channel whose ledger is being updated.
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ChannelName string `json:"channelName"`
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// Namespace within the ledger.
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Namespace string `json:"namespace"`
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// Key name within the ledger namespace.
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Key string `json:"key"`
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// Whether the key and associated value are being deleted.
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IsDelete bool `json:"isDelete"`
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// If `isDelete` is false, the Value written to the key; otherwise ignored.
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Value string `json:"value"`
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}
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// Apply writes for a given transaction to off-chain data store, ideally in a single operation for fault tolerance.
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// This implementation just writes to a file.
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func applyWritesToOffChainStore(data ledgerUpdate) error {
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if err := simulateFailureIfRequired(); err != nil {
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return err
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}
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writes := []string{}
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for _, write := range data.Writes {
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marshaled, err := json.Marshal(write)
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if err != nil {
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return err
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}
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writes = append(writes, string(marshaled))
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}
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f, err := os.OpenFile(storeFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
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if err != nil {
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return err
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}
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if _, err := f.Write([]byte(strings.Join(writes, "\n") + "\n")); err != nil {
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f.Close()
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return err
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}
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if err := f.Close(); err != nil {
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return err
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}
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return nil
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}
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func simulateFailureIfRequired() error {
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if simulatedFailureCount > 0 && transactionCount >= simulatedFailureCount {
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transactionCount = 0
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return errors.New("expected error: simulated write failure")
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}
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transactionCount += 1
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return nil
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}
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func getSimulatedFailureCount() uint {
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valueAsString := envOrDefault("SIMULATED_FAILURE_COUNT", "0")
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result, err := strconv.ParseUint(valueAsString, 10, 0)
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if err != nil {
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panic(fmt.Errorf("invalid SIMULATED_FAILURE_COUNT value: %s", valueAsString))
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}
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return uint(result)
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}
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