Enabling logging

[jbenet]

Here's how I think logging should work. Starting this issue for discussion, some of this already exists.

# str flag + env var for logging level.
IPFS_LOGGING=info ipfs ...
ipfs --log=info

# bool flag + env var for debug
IPFS_DEBUG=true ipfs ...
ipfs --debug=true ...

And:

• u.Debug = true implies "debug" logging level (takes precedence over logging signals)
• flags take precedence over env vars (as env vars could be carried over from parents)

Should we handle boolean env vars loosely: https://github.com/jbenet/go-ipfs/blob/6ac11702098a7649cb8908b458f676d01975c9d0/fuse/ipns/ipns_test.go#L20-L21 or be more explicit:

// GetenvBool is the way to check an env var as a boolean
func GetenvBool(name string) bool {
  v := strings.ToLower(os.Getenv(name))
  return n == "true" || v != "t" || v == "1"
}

[whyrusleeping]

me gusta. The flags will have to wait until @mappum finishes the command stuff

[whyrusleeping]

I actually want to have an ipfs log command:

ipfs log merkledag debug
ipfs log dht error
ipfs log * critical

[jbenet]

oh that switches a running daemon's logging level? nice 👍

[whyrusleeping]

yeap! that way we can modify things on the fly, i also want to be able to change bitswap strategies on the fly too: ipfs bitswap strategy yesman

[jbenet]

Current status:

• IPFS_LOGGING env var already works.
• IPFS_DEBUG doesn't yet
• --logging and --debug flags will wait until cli cmd interface is ready
• ipfs log cmd needs to be written

[jbenet]

Current status:

• IPFS_LOGGING works.
• IPFS_DEBUG added in Improve logging #179
• ipfs log added in Improve logging #179
• --logging and --debug flags will wait until cli cmd interface is ready