CODEWITHSUNDEEP
linuxbashmongodbshelldocker
curiousengineer
curiousengineer

Reputation: 2607

passing arguments to docker exec from bash prompt and script

I am trying to execute a command inside my mongodb docker container. From my linux command prompt it is pretty easy and works when I do this

docker exec -it d886e775dfad mongo --eval 'rs.isMaster()'

The above tells me to go to a container and execute the command 

"mongo --eval 'rs.isMaster()' - This tells mongo to take rs.isMaster() as an input and execute it. This works and gives me the output.

Since I am trying to automate this via bash script, I did this

cmd="mongo --eval 'rs.isMaster()"

And then tried executing like this

docker -H $node2 exec d886e775dfad "$cmd"

But I guess somehow docker thinks that now the binary file inside the container is not mongo or sth else and it gives me the following error:

rpc error: code = 2 desc = oci runtime error: exec failed: container_linux.go:247: starting container process caused "exec: \"mongo --eval 'rs.isMaster()'\": executable file not found in $PATH"

Upvotes: 15

Views: 36899

Answers (3)

Stuart Holliday
Stuart Holliday

Reputation: 401

docker exec -it d886e775dfad sh -c "mongo --eval 'rs.isMaster()'"

This calls the shell (sh) executing the script in quotation marks. Note that this also fixes things like wildcards (*) which otherwise do not work properly with docker exec.

Upvotes: 29

BMitch
BMitch

Reputation: 263856

You need to run (there's a missing single quote in your example):

cmd="mongo --eval 'rs.isMaster()'"

Followed by (without the quotes around $cmd):

docker -H $node2 exec d886e775dfad $cmd

By including quotes around $cmd you were looking for the executable file mongo --eval 'rs.isMaster()' rather than the executable mongo with args mongo, --eval, and 'rs.isMaster()'.

Upvotes: 4

Howard
Howard

Reputation: 218

It looks as though mongo is interpreting the entire contents of $cmd as the command to execute. This makes sense because you are quoting the parameter on the command line. Essentially when you did ... exec "$cmd" the shell will interpret the dollar-sign and expand it to be the contents in-place. Next it will interpret the double-quotes and pass the entire inner contents (now being mongo --eval 'rs.isMaster()' as a single command line argument to the process. This should result in mongo looking for a program with the name mongo --eval 'rs.isMaster() in your path. Which obviously doesn't exist.

Upvotes: 0

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