[Investigation] Allow tealdbg to listen to any address

[fabrice102]

Is your feature request related to a problem? Please describe.

When using tealdbg from inside sandbox (https://github.com/algorand/sandbox), tealdbg needs to allow listening from any address and not just localhost. (This is true on macOS. It is possible that Docker on Ubuntu does not require that.)

Currently, the only solution I know how to use tealdbg inside sandbox is the following:

1. Add - 9392:9392 inside the ports section of docker-compose.yml: https://github.com/algorand/sandbox/blob/0c15c8f5e0256770ef434333fee4ca55bb794ce0/docker-compose.yml#L21
2. Enter sandbox: ./sandbox enter algod
3. Install socat: apt install socat
4. Create TEAL script, e.g., echo "int 1" > a.teal
5. Run tealdbg in the background with new port (e.g., 1234): tealdbg debug --remote-debugging-port 1234 a.teal &
6. Redirect port 1234 to 9392 because 1234 is only bound locally (see netstat below): socat tcp-listen:9392,reuseaddr,fork tcp:localhost:1234
7. Open Chrome Developer tools and visit the address displayed by tealdbg where 1234 is replaced by 9392.

For information: netstat

root@b4a8696ccc6d:~/testnetwork/Node# netstat  -ltnp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:9392            0.0.0.0:*               LISTEN      2794/socat
tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN      14/algod
tcp        0      0 127.0.0.1:1234          0.0.0.0:*               LISTEN      2739/tealdbg
tcp        0      0 127.0.0.1:44739         0.0.0.0:*               LISTEN      14/algod
tcp        0      0 127.0.0.11:42925        0.0.0.0:*               LISTEN      -
tcp6       0      0 :::4001                 :::*                    LISTEN      23/algod
tcp6       0      0 :::4002                 :::*                    LISTEN      32/kmd

Describe the solution you'd like

Add a flag to tealdbg to allow to listen to any address rather than just 127.0.0.1.
That is to change 127.0.0.1 in

go-algorand/cmd/tealdbg/server.go

Line 97 in 693b673

appAddress := fmt.Sprintf("127.0.0.1:%d", port)

.

Additional context

This issue comes from a discussion on Discord.

[pbennett]

Makes sense - is there any reason for it to just not listen on all interfaces? Changing to :%d should suffice.

[ian-algorand]

We need to investigate the feasibility of this request. Thanks for porting this into an issue (from discord @fabrice102 )

[algorandskiy]

@fabrice102 please review the PR I linked.

[atrefonas]

By the way I needed to run "docker-compose up -d" after changing the docker-compose.yml file. Restarting my docker container was not sufficient. Possibly should add it as a step.