Docker Build can't find pip

Question

Trying to follow a few[1][2] simple Docker tutorials via AWS am and getting the following error:

> docker build -t my-app-image .                                         
Sending build context to Docker daemon 94.49 MB
Step 1 : FROM amazon/aws-eb-python:3.4.2-onbuild-3.5.1
# Executing 2 build triggers...
Step 1 : ADD . /var/app
 ---> Using cache
Step 1 : RUN if [ -f /var/app/requirements.txt ]; then /var/app/bin/pip install -r /var/app/requirements.txt; fi
 ---> Running in d48860787e63
/bin/sh: 1: /var/app/bin/pip: not found
The command '/bin/sh -c if [ -f /var/app/requirements.txt ]; then /var/app/bin/pip install -r /var/app/requirements.txt; fi' returned a non-zero code: 127

Dockerfile:

# For Python 3.4
FROM amazon/aws-eb-python:3.4.2-onbuild-3.5.1

Which pip returns the following:

> which pip                                                             
./bin/pip

Relevant file structure:

.
├── Dockerfile
├── bin
│   ├── activate
│   ├── pip
│   ├── pip3
│   ├── pip3.5
│   ├── python -> python3
│   ├── python-config
│   ├── python3
│   ├── python3.5 -> python3
│   .
.

Again, noob in all things Docker so I'm not sure what troubleshooting steps to take. Please let me know what other helpful information I can provide.

Answer 1

I think the issue is how you have organized your bin/pip files

From Docker Documentation: https://docs.docker.com/engine/reference/builder/#add

If <dest> does not end with a trailing slash, it will be considered a regular file and the contents of <src> will be written at <dest>.

So your file structure should be :

.
??? Dockerfile
??? app
|   |__bin
|   |  |
?      ??? activate
?      ??? pip
?      ??? pip3
?      ??? pip3.5
?      ??? python -> python3
?      ??? python-config
?      ??? python3
?      ??? python3.5 -> python3
?      .
.

Answer 2

/var/app/bin/pip suppose to work because the amazon/aws-eb-python:3.4.2-onbuild-3.5.1 Dockerfile includes:

RUN        pip3 install virtualenv
RUN        virtualenv /var/app
RUN        /var/app/bin/pip install --download-cache /src uwsgi

It means when you are using this image as a base image, its two ONBUILD instructions would apply to your current build.

ONBUILD    ADD . /var/app
ONBUILD RUN if [ -f /var/app/requirements.txt ]; then /var/app/bin/pip install -r /var/app/requirements.txt; fi

Try with a simpler Dockerfile, and open a shell session from it, in order to check if /var/app is there, and if pip is correctly installed.
You could also test rebuilding directly the 3.4.2-aws-eb-onbuild image itself, again for testing.