I have an old project from 2 years ago that I would like to put onto another Heroku (so it is accessible if the first one stops working). Originally I build this project on Linux, and now I'm on Windows.
I cloned the Github project, added the .env file (for API calls), and tried to push it to the new Heroku page. It didn't work at first so I installed Nodejs and Python buildpacks. I also renamed master to main.
I've been getting errors & trying to work through them, but I don't understand this last one:
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?
remote: Waiting for release... failed.
After Googling for answers, this is what I've tried sofar:
pip install virtualenv
> Requirement already satisfied:
virtualenv --python C:\Python27\python.exe venv
> 'virtualenv' is not recognized as an internal or external command, operable program or batch file.
python virtualenv --python C:\Python27\python.exe venv
> python: can't open file 'C:\Users\USER\Desktop\PROJECT from PROJECT\virtualenv': [Errno 2] No such file or directory
Any idea what I need to do? I need to create a PYTHONPATH environment variable? Or I need to activate the project in a virtual environment? Or something else?
I was able to copy my old Heroku app onto a different Heroku account:
1: Clone the app from Heroku onto my local machine:
heroku git:clone -a myapp
(Heroku doesn't recommend this because it is not a storage repository. But since I knew my app was working, I wanted the exact working code.)
2: Logout of my first Heroku account and login to my second one. Then change my login credentials in the command line:
heroku login
3: Remove the original Heroku branch:
git remote rm heroku
4: Add the new Heroku branch:
heroku git:remote -a example-app
5: My original app uses React and Python, so I had to make sure both buildpacks were installed in the settings:
heroku/nodejs
heroku/python
6: Try to push to Heroku; this failed for me:
git push heroku main
7: My first error was I didn't specify which version of Python the app needs so Heroku was automatically using the latest one. My app needs old 3.7.1 and Heroku was giving it new 3.10.4. To fix I created a runtime.txt file on the root directory:
python-3.7.13
(Heroku doesn't support 3.7.1 anymore. So I tried 3.7.13, which is the oldest one they do support.)
8: My second error was this:
" ImportError: cannot import name 'FieldDoesNotExist' from 'django.db.models.fields' (/app/.heroku/python/lib/python3.7/site-packages/django/db/models/fields/init.py)"
This is my mistake since I didn't clearly specify which version of Django to use.
9: In the requirements.txt file I changed it to this:
Django==3.0.6
10: And then I was able to push the code to Heroku, the app works just like the original:
git push heroku main
Related
I'm working on deploying my first dash app via heroku. I already did the example deployment given here: https://dash.plotly.com/deployment
which was quick and easy. Now I'm running through the same process with my own dash app, which is much more involved than the example app in the link, but which runs fine locally.
In step 2 given in the link, you initialize an empty git repo and run a new virtualenv, okay. Then you have to reinstall all the app's dependencies into the new virtual env.
This is my question, what are my app dependencies? Are those the modules I install at the top of my apps .py file? such as pandas, numpy, sklearn, etc?
Yes, that's correct. They must be defined in the requirements.txt file in the root of your project.
You can create the file manually or running this command
pip freeze > requirements.txt
The file looks something like this
pandas==1.2.0
numpy==1.19.4
I made a website in node.js and I have used child process to run python scripts and use their results in my website. But when I host my application on heroku, heroku is unable to run the python scripts.
I have noticed that heroku was able to run python scripts which only had inbuilt python packages like sys, json but it was failing for scripts which were using external packages like requests, beautifulsoup.
Attempt-1
I made a requirements.txt file inside the project folder and pushed my code to heroku again. But it was still not working. I noticed that heroku uses the requirements.txt file only for python based web applications but not for node.js applications.
Attempt-2
I made a python virtual env inside the project folder and imported the required python packages into the venv. I then removed gitignore from the venv and pushed the whole venv folder to heroku. It still didn't work.
Please let me know if anyone came across a way to handle this.
You can use a Procfile to specify a command to install the python dependencies then start the server.
Procfile:
web: pip install -r requirements.txt && npm start
Place Procfile in your project's root directory and deploy to heroku.
Solution:
Have a requirements.txt file in your project folder.
After you create a heroku app using "heroku create", heroku will identify your app as python based and will not download any of the node dependencies.
Now, go to your heroku profile and go to your app's settings. There is an option named "Add Buildpack" in there. Click on that and add node.js as one of the buildpacks.
Go back to your project and push it to heroku. This time heroku will identify your app as both python and node.js based and will download all the required files.
Recently I'm learning Flask by the book "Flask Web Development". When I completed the code and deployed it to Heroku, the following error happened:
ImportError: /app/.heroku/python/lib/python3.6/
sitepackages/psycopg2/.libs/libresolv-2-c4c53def.5.so:
symbol __res_maybe_init version GLIBC_PRIVATE not defined
in file libc.so.6 with link time reference
However, this works fine locally. I have searched relevant questions about psycopg2, and I have adjusted the version of psycopg2 but the same error still happens. Please, how can I solve the problem?
I got the same problem. I solved it by forcing heroku to clean up the python virtual environment, and reinstall the requirements.txt file using psycopg2>=2.7,<2.8 --no-binary psycopg2. I must admit it felt a little like magic, but for what its worth here are the steps I took:
Using Git Bash for Windows, I logged in to heroku with heroku login.
Next, I navigated to the root folder of the git/project folder I was working on.
There I made sure that my requirements.txt was updated by running venv/Scripts/pip freeze > requirements.txt. You will probably have to find your own python/virtual environment path.
Next I changed the line/entry for psycopg2 to psycopg2>=2.7,<2.8 --no-binary psycopg2.
Then saved all the content of the requirements.txt file to my desktop, making sure the one in my project folder was empty. Not sure if this step was necessary. But that's what I did, so I'm just gonna mention it here.
Now in the Git Bash terminal I ran heroku apps:info -a blogglistene to find the version of the my heroku stack which for me was heroku-18.
Next I look online for the supported versions of python for heroku-18. It said the default was python-3.6.6 (which I then assumed is the one I was running), and some others.
I then picked python-2.7.15 arbitrarily from the list, and added that text to a runtime.txt file which I placed in the root of my project folder.
Next I committed and pushed this to my heroko git repo, and it was deployed. This will temporarily break the build. From what I understand, the magic behind this is that heroku now fully destroys the python interpreted and environment, so no lingering cached files or anything. Clean slate.
Then I reverted the content of runtime.txt to the default of python-3.6.6 and added back the content of the requirements.txt file, making sure the changes I made are there.
Finally, I committed and pushed this, and my application was back up and running.
I had the exact same problem when I was following "Flask Web Development". I spent a day plus trying to solve it and eventually succeeded. It's not as complicated as André C. Andersen's method.
Make sure you are on master branch. Not other branches.
The book is second edition of Flask Web Development by Miguel Grinberg. Chapter 17. Deployment. When you work all the way till Deploying with git push, after git push heroku master to upload the application to the heroku remote. The application is now deployed and running, but it is not going to work correctly because the deploy command that initializes the database tables has not been executed yet. You need to use
heroku run flask deploy
to create database on heroku. That's where the problem appears.
This is because at this point your git repo HEAD is at 17c. It's not the master branch yet. If you commit any change now, it won't change heroku environment. Meaning when you do
git branch
You will see:
(HEAD detached from 17c)
master
But this is not what you want. Not head attached to 17c. You want to see only master, which is achieved with
git checkout master
Then git branch will show only master branch. Therefore you can make adjustments on the project and heroku will update. Doing this because you will eventually git push to master branch. I think you can git push to other branches in order for heroku to work, but I don't know how to do that.
Change psycopg2==2.7.3 to the newest version, e.g. psycopg2==2.8.4. Another workaround is to change it to psycopg2-binary==2.8.3.
psycopg2 2.7.3 will give you GLIBC_PRIVATE error. (You can check it by running heroku run bash, then starting python and importing psycopg2. If heroku dependency is 2.7.3, then you will see the same error.) The official website notes that version 2.7.3.1 drops libresolv which causes the issue, therefore using this version or later should do the trick.
Now, change your requirements/heroku.txt (heroku environment dependency) line psycopg2==2.7.3 to psycopg2--2.8.4 or psycopg2-binary==2.8.3. (For some reason binary version of psycopg2 will work without issue. Don't know why, but I saw A LOT of discussion on stackover.) Then,
git add .
git commit -m "notes"
As usual.
git push heroku master
Push to heroku master branch. If you do not do step 1, then git will show Everything up-to-date. Therefore, it won't make changes because you are committing not to master. Now, you can see git is downloading the appropriate package.
You can double check if the packages are correct by opening heroku bash then pip list. You will see psycopg2 (and psycopg2-binary if you chose the workaround). Now, when you start Python, you can import psycopg2 with no problem.
Finally. heroku run flask deploy. Voila!
I was stuck on step 1, since whatever change I made with the project, heroku just didn't update.
This is my first experience deploying a Flask web app to Azure.
I followed this tutorial.
The default demo app they have works fine for me.
Afterwards, I pushed my Flask app via git. The log shows deployment was successful. However, when I browse the hosted app via link provided in "Application Properties", I get a 500 error as follows:
The page cannot be displayed because an internal server error has
occurred.
Most likely causes: IIS received the request; however, an internal
error occurred during the processing of the request. The root cause of
this error depends on which module handles the request and what was
happening in the worker process when this error occurred. IIS was not
able to access the web.config file for the Web site or application.
This can occur if the NTFS permissions are set incorrectly. IIS was
not able to process configuration for the Web site or application. The
authenticated user does not have permission to use this DLL. The
request is mapped to a managed handler but the .NET Extensibility
Feature is not installed.
The only off-base thing I can see by browsing the wwwroot via KUDU is that none of the packages I have installed in my local virtual environment are installed on Azure despite the existence of the "requirements.txt" file in wwwroot.
My understanding is that Azure would pip install any non existent package that it finds in the requirements.txt upon GIT successful push. But it doesn't seem to be happening for me.
Am I doing something wrong and the missing packages is just a symptom or could it be the cause the issue?
Notes:
My Flask app works fine locally (linux) and on a 3rd party VPS
I redeployed several times starting from scratch to no avail (I use local GIT method)
I cloned the Azure Flask demo app locally, changed just the app folder and pushed back to Azure, yet no success.
Azure is set to Python 2.7 same as my virtual env locally
As suggested in the tutorial linked above, I deleted the "env" folder and redeployed to trick Azure to reinstall the virtual env. It did but with its own default packages not the one in my requirements.txt.
My requirements.txt has the following:
bcrypt==3.1.0 cffi==1.7.0 click==6.6 Flask==0.11.1 Flask-Bcrypt==0.7.1
Flask-Login==0.3.2 Flask-SQLAlchemy==2.1 Flask-WTF==0.12
itsdangerous==0.24 Jinja2==2.8 MarkupSafe==0.23 pycparser==2.14
PyMySQL==0.7.7 python-http-client==1.2.3 six==1.10.0 smtpapi==0.3.1
SQLAlchemy==1.0.14 Werkzeug==0.11.10 WTForms==2.1
As Azure Web Apps will run a deploy.cmd script as the deployment task to control which commands or tasks will be run during the deployment.
You can use the command of Azure-CLI azure site deploymentscript --python to get the python applications' deployment task script.
And you can find the following script in this deploy.cmd sciprt:
IF NOT EXIST "%DEPLOYMENT_TARGET%\requirements.txt" goto postPython
IF EXIST "%DEPLOYMENT_TARGET%\.skipPythonDeployment" goto postPython
echo Detected requirements.txt. You can skip Python specific steps with a .skipPythonDeployment file.
So the .skipPythonDeployment will skip all the following steps in deployment task, including creating virtual environment.
You can try to remove .skipPythonDeployment from your application, and try again.
Additionally, please refer to https://github.com/projectkudu/kudu/wiki/Custom-Deployment-Script for more info.
I am trying to deploy my Pyramid app on Heroku and no matter what I do, I get the failed to detect buildpack error message after I try to push.
I have my requirements.txt from my pip freeze in there next to my setup.py as well as my Procfile and runapp.py. I am not using my master branch for Heroku and have been using
git push heroku local_branch:master
I have also tried to set the build pack manually by using
heroku buildpacks:set heroku/python
I also have tried using external buildpacks from github, but that also does not work. I must be missing something in my requirements.txt?
Also, I have read Pyramid's Docs on Heroku deployment as well as Heroku's. I have browsed here for help but all I can find is that to make sure requirements.txt is spelled correctly or just re-init my git.
Add a "requirements.txt" file to the root directory of your repository.