137 lines
2.7 KiB
Go
137 lines
2.7 KiB
Go
package client
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import (
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"sort"
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"go.uber.org/zap"
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)
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// Endpoint represents morph endpoint together with its priority.
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type Endpoint struct {
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Address string
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Priority int
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}
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type endpoints struct {
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curr int
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list []Endpoint
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}
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func (e *endpoints) init(ee []Endpoint) {
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sort.SliceStable(ee, func(i, j int) bool {
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return ee[i].Priority > ee[j].Priority
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})
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e.curr = 0
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e.list = ee
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}
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func (c *Client) switchRPC() bool {
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c.switchLock.Lock()
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defer c.switchLock.Unlock()
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c.client.Close()
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// Iterate endpoints in the order of decreasing priority.
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// Skip the current endpoint.
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for c.endpoints.curr = range c.endpoints.list {
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newEndpoint := c.endpoints.list[c.endpoints.curr].Address
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cli, err := newWSClient(c.cfg, newEndpoint)
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if err != nil {
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c.logger.Warn("could not establish connection to the switched RPC node",
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zap.String("endpoint", newEndpoint),
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zap.Error(err),
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)
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continue
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}
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err = cli.Init()
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if err != nil {
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cli.Close()
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c.logger.Warn("could not init the switched RPC node",
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zap.String("endpoint", newEndpoint),
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zap.Error(err),
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)
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continue
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}
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c.cache.invalidate()
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c.client = cli
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c.logger.Info("connection to the new RPC node has been established",
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zap.String("endpoint", newEndpoint))
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if !c.restoreSubscriptions(newEndpoint) {
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// new WS client does not allow
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// restoring subscription, client
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// could not work correctly =>
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// closing connection to RPC node
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// to switch to another one
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cli.Close()
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continue
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}
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return true
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}
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return false
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}
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func (c *Client) notificationLoop() {
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for {
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select {
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case <-c.cfg.ctx.Done():
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_ = c.UnsubscribeAll()
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c.close()
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return
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case <-c.closeChan:
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_ = c.UnsubscribeAll()
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c.close()
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return
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case n, ok := <-c.client.Notifications:
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// notification channel is used as a connection
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// state: if it is closed, the connection is
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// considered to be lost
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if !ok {
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var closeReason string
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if closeErr := c.client.GetError(); closeErr != nil {
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closeReason = closeErr.Error()
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} else {
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closeReason = "unknown"
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}
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c.logger.Warn("switching to the next RPC node",
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zap.String("reason", closeReason),
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)
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if !c.switchRPC() {
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c.logger.Error("could not establish connection to any RPC node")
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// could not connect to all endpoints =>
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// switch client to inactive mode
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c.inactiveMode()
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return
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}
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// TODO(@carpawell): call here some callback retrieved in constructor
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// of the client to allow checking chain state since during switch
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// process some notification could be lost
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continue
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}
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c.notifications <- n
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}
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}
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}
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// close closes notification channel and wrapped WS client
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func (c *Client) close() {
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close(c.notifications)
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c.client.Close()
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}
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