How to format output from a program spawned from a expect script - tcl

Question

I am writing a load testing script for radius server using tcl and expect.
I am invoking radclient, that comes inbuild with the radius server, from my script on remote server.
scripts does following:
take remote server IP
- spawn ssh to remote server
- invoke radclient
- perform load test using radclient commands
- need to collect the result from the output (as shown in the sample output) into a variable
- Extract authentication/sec as Transaction per second (TPS) from output or variable from previous step
Need help on last two steps:
Sample output from radclient:
*--> timetest 20 10 2 1 1
Cycles: 10, Repetitions: 2, Requests per Cycle: 10
Starting User Number: 1, Increment: 1
Current Repetition Number=1
Skipping Accounting On Request
Total Requests=100, Total Responses=100, Total Accepts=0 Total Not Accepts=100
1: Sending 100 requests and getting 100 responses took 449ms, or 0.00 authentications/sec
Current Repetition Number=2
Skipping Accounting On Request
Total Requests=100, Total Responses=100, Total Accepts=0 Total Not Accepts=100
2: Sending 100 requests and getting 100 responses took 471ms, or 0.00 authentications/sec
Expected Output:
TPS achieved = 0

Answer 1

You might use something like this:
expect -re {([\d.]+) authentications/sec}
set authPerSec $expect_out(1,string)
puts "TPS achieved = $authPerSec"
However, that's not to say that the information extracted is the right information. For example, when run against your test data it is likely to come unstuck as there are two places where you have authentications/sec due to all the repetitions; we don't account for that at all! More complex patterns might extract more information and so on.
expect {
-re {([\d.]+) authentications/sec} {
set authPerSec $expect_out(1,string)
puts "TPS achieved #[incr count] = $authPerSec"
exp_continue
}
"bash$" {
# System prompt means stop expecting; tune for what you've got...
}
}
Doing the right thing can be complex sometimes…