[POA-1340] Add a mechanism to randomly _not_ start apidump.

[mgritter]

Controlled by a flag and a new environment variable.

The use case here is that we want to run the agent but some, but not all, of the pods in a critical deployment. This is not a great solution, but it's much easier than the alternatives considered. The deployment can include a probability as an environment variable that any given apidump command will run; those that don't run will just hang forever to avoid any problems caused by container exit.

One downside is that changing the environment variable causes all the pods to be restarted.

[mgritter]

The environment variable is not working and I can't tell why:

mark@ubuntu:~/akita-cli$ docker run -e POSTMAN_ENV=beta -e POSTMAN_API_KEY=PMAK-xxx -e POSTMAN_AGENT_RANDOM_START=0 postman-insights-agent-release:0.30.8-rc1 apidump --project svc_5xtgTmKcZxgasmGQwsbMR0  --randomized-start=0
[INFO] Postman Insights Agent 0.30.8-rc1
[INFO] Starting trace with probability 0%.
[INFO] This agent instance will not begin capturing data.
^Cmark@ubuntu:~/akita-cli$ docker run -e POSTMAN_ENV=beta -e POSTMAN_API_KEY=PMAK-xxx -e POSTMAN_AGENT_RANDOM_START=0 postman-insights-agent-release:0.30.8-rc1 apidump --project svc_5xtgTmKcZxgasmGQwsbMR0 
[INFO] Postman Insights Agent 0.30.8-rc1
[INFO] Created new trace on Postman Cloud: akita://Mark test 2024-06-25:trace:pickle-neck-04540b68
[INFO] Running learn mode on interfaces lo, eth0
[INFO] --filter flag is not set; capturing all network traffic to and from your services.
[INFO] Send SIGINT (Ctrl-C) to stop...
^C[INFO] Received interrupt, stopping trace collection...

[mgritter]

Another problem here is that Go prior to 1.20 does not seed its RNG automatically. And we use 1.18 to build.

[mudit-postman]

When will this be called?

[mgritter]

Never, that's why it's marked unreachable (and the linter will tell you so too.)

I just felt it was more robust to have it here in case the select was later modified.

[mudit-postman]

We should create a ticket to upgrade agent to build on go 1.21