Some pip packages fail to access their own dist-info in Debug but not Run

[chkothe]

Describe the bug Some packages use pkg_resource.get_distribution() at runtime (e.g., to find their own version) and for some packages this seems to fail in Debug mode, while it succeeds in Run mode (e.g., jsonschema==3.0.1).

To reproduce

1. Create new AWS Serverless Application project from hello-world template
2. Add jsonschema==3.0.1 to requirements.txt
3. In launch configuration settings, switch SAM CLI to "Build function inside container"
4. import jsonschema in app.py
5. Click Run and observe that it succeeds
6. Click Debug and observe that it fails with the error:

   
   "C:\Program Files\Amazon\AWSSAMCLI\bin\sam.cmd" local invoke --template C:\Users\chris\AppData\Local\Temp\lambdaBuild2884\template.yaml --event "C:\Users\chris\AppData\Local\Temp\[Local] HelloWorldFunction-event3586.json" HelloWorldFunction --debug-port 56537 --debugger-path "C:\Program Files\JetBrains\PyCharm 2019.1.1\helpers\pydev" --debug-args "-u /tmp/lambci_debug_files/pydevd.py --multiprocess --port 56537 --file"
   2019-06-26 16:10:17 Invoking app.lambda_handler (python3.7)
   2019-06-26 16:10:17 Found credentials in environment variables.

Fetching lambci/lambda:python3.7 Docker container image...... 2019-06-26 16:10:19 Mounting C:\Users\chris\AppData\Local\Temp\lambdaBuild2884\HelloWorldFunction as /var/task:ro,delegated inside runtime container Connected to pydev debugger (build 191.7479.30)     raise DistributionNotFound(req, requirers) START RequestId: 52fdfc07-2182-154f-163f-5f0f9a621d72 Version: $LATEST END RequestId: 52fdfc07-2182-154f-163f-5f0f9a621d72 REPORT RequestId: 52fdfc07-2182-154f-163f-5f0f9a621d72 Init Duration: 1309.12 ms Duration: 0.00 ms Billed Duration: 100 ms Memory Size: 128 MB Max Memory Used: 34 MB
{ "errorType": "DistributionNotFound", "errorMessage": "The 'jsonschema' distribution was not found and is required by the application", "stackTrace": [ " File \"/var/lang/lib/python3.7/imp.py\", line 234, in load_module\n return load_source(name, filename, file)\n", " File \"/var/lang/lib/python3.7/imp.py\", line 171, in load_source\n module = _load(spec)\n", " File \"\u003cfrozen importlib._bootstrap\u003e\", line 696, in _load\n", " File \"\u003cfrozen importlib._bootstrap\u003e\", line 677, in _load_unlocked\n", " File \"\u003cfrozen importlib._bootstrap_external\u003e\", line 728, in exec_module\n", " File \"\u003cfrozen importlib._bootstrap\u003e\", line 219, in _call_with_frames_removed\n", " File \"/var/task/app.py\", line 3, in \u003cmodule\u003e\n import jsonschema\n", " File \"/var/task/jsonschema/init.py\", line 33, in \u003cmodule\u003e\n version = get_distribution(name).version\n", " File \"/var/lang/lib/python3.7/site-packages/pkg_resources/init.py\", line 481, in get_distribution\n dist = get_provider(dist)\n", " File \"/var/lang/lib/python3.7/site-packages/pkg_resources/init.py\", line 357, in get_provider\n return working_set.find(moduleOrReq) or require(str(moduleOrReq))[0]\n", " File \"/var/lang/lib/python3.7/site-packages/pkg_resources/init.py\", line 900, in require\n needed = self.resolve(parse_requirements(requirements))\n", " File \"/var/lang/lib/python3.7/site-packages/pkg_resources/init.py\", line 786, in resolve\n raise DistributionNotFound(req, requirers)\n" ] }

**Expected behavior**
Importing the package succeeds like it does in Run mode.

**Your Environment**
- OS: Windows 10 1803 x64
- JetBrains' Product: PyCharm Professional Edition
- JetBrains' Product Version: 2019.1.3 (Build #PY-191.7479.30, built on May 29, 2019)
- Toolkit Version: v1.4
- SAM CLI Version: 0.17.0
- JVM/Python Version: Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32
- Docker Desktop Version: Community Edition, Version 2.0.0.3 (31259)

**Additional context**
Not using the SAM CLI option "Build function inside container" causes the build to fail with a pip PythonPipBuilder:ResolveDependencies error, which may or may not be related:

"C:\Program Files\Amazon\AWSSAMCLI\bin\sam.cmd" build --template C:\DEVEL\SAM\test4\template.yaml --build-dir C:\Users\chris\AppData\Local\Temp\lambdaBuild49 2019-06-26 16:20:32 Building resource 'HelloWorldFunction' 2019-06-26 16:20:32 Running PythonPipBuilder:ResolveDependencies Error: PythonPipBuilder:ResolveDependencies - list index out of range

[abrooksv]

Was able to replicate

[abrooksv]

Outside of SAM command:

/Users/alfredbr/IdeaProjects/SamMaven/venv/bin/python /Users/alfredbr/aws-intellij-toolkit/jetbrains-core/build/idea-sandbox/plugins/python-ce/helpers/pydev/pydevd.py --multiproc --qt-support=auto --client 127.0.0.1 --port 50466 --file /Users/alfredbr/IdeaProjects/PythonSam/hello_world/app.py

Inside of SAM command:

/var/lang/bin/python3.7 -u /tmp/lambci_debug_files/pydevd.py --DEBUG --multiprocess --port. 51971 --file /var/runtime/bootstrap

[abrooksv]

Using the lambda image as a remote python interpreter results in:

python -u /opt/.pycharm_helpers/pydev/pydevd.py --multiprocess --qt-support=auto --port 53737 --file /opt/project/hello_world/app.py

Which maps with what we do in SAM and it does work.

[abrooksv]

So I have a work around, but I do not know why pydevd is requiring it.

Add

      Environment:
        Variables:
          PYTHONPATH: '/var/task'

to your template.yaml.

I don't see a way I can fix this in the toolkit, since the toolkit can only add environment variables if already defined in your template.

[chkothe]

Ok good to know!

[abrooksv]

Okay, I see. Pydev adds the directory of argument to --file into sys path using sys.path(0, ...), but that is /var/runtime, not /var/task. (https://github.com/fabioz/PyDev.Debugger/blob/fff160b1327e248eb847f5adc70113f1fb60b8e5/pydevd.py#L1770)

[abrooksv]

I tried to put pydevd into module module, but that just led to failing to start.

('Bound to port ', '61540')
('Connection accepted',)
debugger: received >>501    1   0.1 UNIX
<<
Received command: CMD_VERSION 501   1   0.1 UNIX

sending cmd -->          CMD_VERSION 501    1   @@BUILD_NUMBER@@ 
Connected to pydev debugger (build 191.6183.87)
debugger: received >>501    3   0.1 UNIX
<<
Received command: CMD_VERSION 501   3   0.1 UNIX

sending cmd -->          CMD_VERSION 501    3   @@BUILD_NUMBER@@ 
debugger: received >>111    5   python-line /var/task/app.py    38  lambda_handler  THREAD  None    None
<<
Received command: CMD_SET_BREAK 111 5   python-line /var/task/app.py    38  lambda_handler  THREAD  None    None

Added breakpoint:/var/task/app.py - line:38 - func_name:b'lambda_handler'

debugger: received >>122    7   python-BaseException    None    None    0   1   0
146 9   SHOW_RETURN_VALUES  0
101 11  
<<
Received command: CMD_ADD_EXCEPTION_BREAK 122   7   python-BaseException    None    None    0   1   0

Exceptions to hook on terminate: {'BaseException': <_pydevd_bundle.pydevd_breakpoints.ExceptionBreakpoint object at 0x7f4001e166d8>}

Received command: CMD_SHOW_RETURN_VALUES 146    9   SHOW_RETURN_VALUES  0

Show return values: False

Received command: CMD_RUN 101   11  

No module named /var/runtime/bootstrap