Detect if Bitcoin is running?

[Rena]

What would be the proper/best way for a script to tell if bitcoin[d] is running? I'm writing a Lua script that calls `bitcoin getinfo` and similar commands, and I see it outputs a message to stderr if the server isn't running, but Lua doesn't provide any standard way to read stderr, so I was hoping there's another way to check?

[BioMike]

# ps|grep bitcoind

That is how I normally do a quick check if services are running.

[theymos]

Code:

if curl -s 127.0.0.1:8332 >/dev/null; then
echo "running"
else
echo "not running"
fi

Edit: Another way (faster):

Code:

if /sbin/ss -l |grep -q "127.0.0.1:8332"; then
echo "running"
else
echo "not running"
fi

[Rena]

Hmm, both of those rely on Unix shell commands and redirection. I was hoping for something like a PID file I can check that only exists when the server is running. I can do similar just by appending 2>&1 to the command I call from Lua, but as far as I know there's no guarantee that io.popen() will actually execute the command the way a shell would rather than, for example, just passing everything after the first space as the parameter to the program being called.
I can use sockets as well, but that requires adding LuaSocket, and I was hoping not to depend on any external libraries. Lua doesn't provide much on its own (it focuses on being simple and lightweight) so that may prove difficult to avoid...

[theymos]

There is a .lock file in the data directory, though I don't know how reliable this is. Maybe it only appears when Bitcoin is doing something to the database.

You could parse /proc/net/tcp.

[genjix]

Use my branch and do getinfo

https://github.com/genjix/bitcoin/tree/isinitialized

[Rena]

That's the kind of thing I was looking for. Of course that means anyone using my script also has to use that branch. Will that change be in the official client in some future version?

[Gavin Andresen]

Hmm, both of those rely on Unix shell commands and redirection. I was hoping for something like a PID file..

I pulled a patch that makes Linux/Mac bitcoin/bitcoind write a bitcoind.pid file when started with the -daemon switch (and erases it on shutdown).

Next release will have several changes to make startup on Linux/Mac more unix-standard-like.