Docker image gives me “executable file not found in $PATH” when run from python

Question

I'm trying to run some commands inside a docker image in python. When I do:

docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh -c "javac example.java && java example"

In console (kali linux) it runs fine and prints the result. When I try to run same command from python it gives me the error:

"Exception: docker: Error response from daemon: oci runtime error: exec: \"sh -c 'javac example.java && java example'\": executable file not found in $PATH.\n"

These lines work fine from python:

docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim javac
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim javac example.java

But these don't:

docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh javac
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh javac example.java
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh -c javac
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim sh -c "javac"

They all work from console. Just not from python. As soon as I add "sh -c" it gives me the error. I can run it as 2 separate commands like:

docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim javac example.java
docker run --rm -v <some_dir>:/mnt --workdir /mnt frolvlad/alpine-oraclejdk8:slim java example

But it's important that it runs all at once.

It all works fine from console, but in python as soon as I add "sh -c" it gives me the error. What am I doing wrong?

Here is the python code that I use:

BASE_CMD = [
    'docker',
    'run',
    '--rm',
    '-v'
]

def calculate_compile_and_execute_java_command(folder_name, file_name):
    return BASE_CMD + [
        folder_name + ":/mnt",
        "--workdir",
        "/mnt",
        "frolvlad/alpine-oraclejdk8:slim",
        "sh -c 'javac " + file_name + " && java " + file_name[:-5] + "'"
    ]
.
.
.
response = call_command(calculate_compile_and_execute_command(self.lang, file_path, file_name))
.
.
.
def call_command(cmd, timeout=float('inf'), cwd=None, decode=True, **subproc_options):
    if cwd is None:
        cwd = os.getcwd()

    subproc = subprocess.Popen(
        cmd,
        cwd=cwd,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        **subproc_options
    )
    .
    .
    # code for timeout handling and result polling
    .
    .

I tried all possible combinations of string concatenation and quotes escaping in calculate method. Popen() sends the string to terminal as it should. It just doesn't work with "sh -c". It even works if I add more switches to the command. Like this:

def calculate_compile_and_execute_c_command(folder_name, file_name):
    return BASE_CMD + [
        folder_name + ':/mnt',
        'frolvlad/alpine-gcc',
        'gcc',
        '--static',
        '/mnt/' + file_name,
        '-o',
        '/mnt/qq'
    ]

Which gives the string like this:

docker run --rm -v "$(pwd)":/mnt --workdir /mnt frolvlad/alpine-gcc gcc --static qq.c -o qq

Answer 1

You are passing one big string as the last parameter to Docker. Docker is trying to run a binary called sh -c 'javac example.java && java example' which obviously doesn't exist.

You want to run the sh binary with 2 arguments. -c and the shell script you want sh to run.

return BASE_CMD + [
    folder_name + ":/mnt",
    "--workdir",
    "/mnt",
    "frolvlad/alpine-oraclejdk8:slim",
    "sh", 
    "-c",
    "javac " + file_name + " && java " + file_name[:-5]
]

If a command line script becomes too complex, you can hide it behind a shell script

#!/bin/sh
set -ue
javac $1
java ${1%.*}

Then

$ compile_and_run.sh whatever.java