Description
Advanced Distributed Systems
The object of this assignment is to understand and implement At-Most-Once Semantics scenarios
using rpc in golang.
Assume you are developing a software for a bank ABC using Golang. You need to implement the
following functionalities. The client and server templates are attached. Comments are added in the
files, please make use of it.
Server side:
Implement the logic to read the Transactions id from Trans_Processed.txt file, add into the
TransIds[] array, during the starting of the server.
GetBalance()
Func (l *Listener) GetBalance(args *Request, reply *Response)
error
Logic to be implemented
• Whenever a request comes from client read the TransNo from the Request and check
whether the transaction is already processed.
• If it is processed add a message “The transaction already processed.” to the
Response(Response.Data) and return from the client.
• Otherwise (If transaction is not processed) read the balance amount from the Balance.txt and
add the amount in Response. Add the TransNo into TransIds[] array and
Trans_Processed.txt file also.
DepositeAmount()
func (l *Listener) DepositeAmount(args *Request, reply *Reply)
error
Logic to be implemented
• Whenever a request comes from client read the TransNo from the Request and check
whether the transaction is already processed.
• If it is processed add a message “The transaction already processed.” to the
Response(Response.Data) and return from the client.
• Otherwise (If transaction is not processed) read the balance amount from the Balance.txt
amount. Read the amount from Request and add this amount with the balance and delete the
balance amount from the file and add the new balance amount into Balance.txt file.
• Add a message into the Response.Data “Your Amount is deposited into the account
successfully.”.
Client:
Write a client program to connect the client into the server and do the following
1. No Duplicate Entry
Request1: Call the GetBalance() method by adding TransNo into the request.
Request2: Wiat for a second and call the GetBalance()method again by adding different
TransNo into the request.
Expected Output:
Response1: Print the balance amount on console.
Response2: Print the balance amount on console.
2. Duplicate Entry:
Request3: Call the GetBalance() method by adding TransNo into the request.
Request4: Wait for a second and call the GetBalance()method again by adding same
TransNo into the request.
Expected Output:
Response3: Print the balance amount on console.
Response4: The transaction already processed.
3. Deposite the Amount
Request5: Call the DepositeAmount() method by adding TransNo and Amount into the
Request.
Request6: Call the GetBalance() method by adding new TransNo into the request.
Expected Output:
Response5: Your Amount is deposited into the account successfully.
Response6: Print the balance amount on console.
4. Server Crash
Request7: Call the DepositeAmount() method by adding TransNo and Amount into the
Request.
Introduce some delay in server after updating the balance and before sending the response back to
the client. Then stop the server. Start the server again
Request8: Stop the client and start again now this time call the
DepositeAmount()method again by adding same TransNo and Amount into the
Request.
Request9: Call the GetBalance() method by adding new TransNo into the request.
Expected Output:
Response7: Client will not receive the response
Response8: The transaction already processed.
Response9: Print the balance amount on console.
Assumptions:
• At a given time only one client will get connected to the server
• No Authenticate is required
Note: You can make any other suitable assumptions while implementing and same needs to be
added in the readme file.
Resources:
client.go
server.go
Balance.txt
Trans_Processed.txt
Grading – 20 Marks
Client.go – 9 Marks
Server.go – 10 Marks
Readme.txt – 1 Marks
Note:
1. Penalty of 10% per day will be issued if the deadline is not met
2. If found copied, you will fetch 0 score.
Submission Details:
1. Please read the questions carefully and complete it.
2. Make a directory with name
and output file to that folder.
3. Implement the solution using GoLang.
4. Please take screen shot of output, name it with its question number and put it in a same folder.
5. Test well before submission. Follow some coding style uniformly. Provide proper comments
in your code.
6. Submit only through moodle and well in advance. Any hiccups in the moodle/Internet at the
last minute is never acceptable as an excuse for late submission. Submissions through email
will be ignored.
7. Please attach a readme.txt file
8. Please zip your folder and submit to moodle within 20-09-2020 (23:55 PM)
References:
https://medium.com/rungo/building-rpc-remote-procedure-call-network-in-go-5bfebe90f7e9
https://ops.tips/gists/ example-go-rpc-client-and-server/
