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Feature/find successor #33

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Feature/find successor #33

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52c7a51
Merge branch 'project1-master' of https://github.com/bama4/Projects i…
mohitkhatwani Apr 9, 2018
aedec6f
Merge branch 'project1-master' of https://github.com/bama4/Projects i…
mohitkhatwani Apr 14, 2018
7311d11
Merge branch 'project1-master' of https://github.com/bama4/Projects i…
mohitkhatwani Apr 14, 2018
b9ba3dc
Merge branch 'project1-master' of https://github.com/bama4/Projects i…
mohitkhatwani Apr 14, 2018
9e4f9d8
added findSuccessor module
mohitkhatwani Apr 14, 2018
6d7f000
Added findSucc
mohitkhatwani Apr 14, 2018
fd5320f
Changed message_defs to string
mohitkhatwani Apr 14, 2018
ca1866c
Changed All id's to int64
mohitkhatwani Apr 14, 2018
a20494b
Changed main.go
mohitkhatwani Apr 14, 2018
fc5ffc1
Changed for loop start index
mohitkhatwani Apr 14, 2018
f2987c9
Changed iteration of fingerTable and func arguments
mohitkhatwani Apr 14, 2018
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26 changes: 26 additions & 0 deletions PROJ1/findSuccessor/findSuccessor.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
package findSuccessor

import (
nodeDefs "../utils/node_defs"
)

//FindSuccessor ... This function is used to find successor of node with ID targetID
func FindSuccessor(sponsoringNode *nodeDefs.Node, targetID int64) (successor *nodeDefs.Node) {
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The sponsoring node is represented as an int64 (if you look at the join ring function in the code, the *node object is the node that needs a successor...that way you wont have to return a successor object. You will already have the node object that needs a successor, and can assign the correct successor to that node object directly)

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Yeah I thought passing Node instead of only its ID would be nice because FindSucc needs access to successor of sponsoring node which will be available in its node structure.
If we pass only ID then we will need the information of nodes_in_ring so that we can link that ID with its node and then find the successor

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@bama4 bama4 Apr 14, 2018 •
edited
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Oh ok. I think then that passing the sponsoring node as a node object is fine then here. Do you think though that the node that needs the successor should also be an argument so that you can update its successor once you find it?

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I think by the notes in the HW it says it's only responding to a node ID.. which is then used to lookup the specific node in ring_nodes which can also be used to look up the node's successor/predecessor..etc

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Oh ok. I think that is fine then. respond-to is the node that needs a successor right? The function would just need to be in the main file so that you can use the respond-to id to lookup the node respond-to object to update its successor.

if targetID > sponsoringNode.ChannelId && targetID <= sponsoringNode.Successor.ChannelId {
successor = sponsoringNode.Successor
} else {
precedingNode := findClosestPrecedingNode(sponsoringNode, targetID)
successor = FindSuccessor(precedingNode, targetID)
}
return successor
}

func findClosestPrecedingNode(sponsoringNode *nodeDefs.Node, targetID int64) (precedingNode *nodeDefs.Node) {

for i := range sponsoringNode.FingerTable {
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I think based on the pseudocode in the paper, you should find the closest preceding node by starting from the end of the fingertable

if sponsoringNode.FingerTable[int64(i)].ChannelId > sponsoringNode.ChannelId && sponsoringNode.FingerTable[int64(i)].ChannelId < targetID {
precedingNode = sponsoringNode.FingerTable[int64(i)]
}
}
return
}
2 changes: 1 addition & 1 deletion PROJ1/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -172,7 +172,7 @@ func net_node(channel_id int64){
if val, ok := ring_nodes[channel_id]; ok != true {
_ = val
sponsoring_node_id := message.SponsoringNode
join.Join_ring(sponsoring_node_id, &node_obj)
join.Join_ring(int64(sponsoring_node_id), &node_obj)
ring_nodes[channel_id] = &node_obj
}else{
log.Printf("\nNode %d is already in the ring; cannot join-ring\n", channel_id)
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14 changes: 7 additions & 7 deletions PROJ1/utils/message_defs/message_defs.go
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Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
package message_defs


/*
This struct defines the json messages for the
CHORD protocol.
Expand All @@ -13,14 +12,15 @@ respond_to - The node (represented as a channel id) to direct the given action t
data - The key/value pair in the ring representing a hash entry.
*/
type Message struct {
Do string `json:"do"`
SponsoringNode int64 `json:"sponsoring_node"`
Mode string `json:"mode"`
RespondTo string `json:"respond_to"`
Data Data `json:"data"`
Do string `json:"do"`
SponsoringNode int64 `json:"sponsoring-node"`
Mode string `json:"mode"`
RespondTo int64 `json:"respond-to"`
Data Data `json:"data"`
TargetID int64 `json:"target-id"`
}

type Data struct {
Key string `json:"string"`
Key string `json:"string"`
Value string `json:"string"`
}