In class today, I had a problem getting the rootless docker system installed. I just reran the install procedure and now everything is working fine... I have no idea what has caused this change, but hopefully the install will work for you all now too.

Recall that in order to earn a grade that is at least an A- in this class, you must either read a section of The Art of Unix Programming or watch two documentaries. (Details and links are in the syllabus.) In order to get credit for having completed this assignment, you should reply to this post with a 2-3 sentence description of your favorite part of the reading/viewing.

Should we be using the /data/twitter_corona or the /data-fast/twitter2020 dataset for the Twitter homework? I see both referenced in the README.

Hi professor,

I am trying again to download the file. I tried to do manual installation and I am not even able to extract the file.

Here is my disk usage in home, it is tiny, but I am still not able to extract the file.

///lambda-server:~/.cache $ du -h 124M ./docker 190M .

Here is the error
tar: docker/docker-init: Cannot write: Disk quota exceeded docker/docker-proxy tar: docker/docker-proxy: Cannot write: Disk quota exceeded

S&P Global is sponsoring a FinTech hackathon for the Claremont Colleges that will run from April 5th-16th. You can find more details at: https://app.smartsheet.com/b/form/be93833089ff4cbfa01ab4b8195ad7bb

For questions, contact Prof. Nishant Dass at [email protected].

Hello. I read the previous issue on the outdated syntax for the Dockerfile.prod and am using the https://github.com/mikeizbicki/cmc-csci143/blob/2021spring/week_02/Dockerfile.prod file, but I am running into an error even before that step on the line RUN flake8 --ignore=E501,F401 .

The flake8 call lists out lots of problems on the style of the files in env/ (primarily in env/lib/python3.6/site-packages/setuptools) and exits with
The command '/bin/sh -c flake8 --ignore=E501,F401 .' returned a non-zero code: 1
ERROR: Service 'web' failed to build

If I comment out the flake8 line, docker is able to build as normal.

I'm not going to be able to make the 10-11am lab time this week because I'm a speaker at a CMC event on algorithmic bias. If you'd like to have lab this week, then reply to this message with a suggested time. (See my calendar to ensure that I'm free too.) We'll do whatever time has a consensus.

Note: Shoutout to An for pointing out to me that my variable name is wrong (earlier issue, now reopened) :')

Like mentioned in issue #31 I keep getting

-bash: fork: retry: Resource temporarily unavailable

I fixed some pieces of my code after running nohup.
Currently my output folder only has .lang zip files. To fix this, I tried rerunning nohup ./run_maps.sh but it doesn't seem like .country zip files are being added to outputs. Any suggestions would be appreciated. Thanks! :)

My wife has gone into labor, and so I'm helping her deliver a baby :) I won't be available for class or office hours on Monday (Mar 29), so they're both cancelled. We should have class/office hours on Wednesday (Mar 31) like normal.

Since I won't be available for homework questions like normal on Monday, I will give everyone a blanket extension on the homework until Thursday at midnight. This will give you a chance to ask any questions on Wednesday, and still have some time to work on the assignment.

Hi there! Curtis and I are facing the same issue, any help would be appreciated. Thank you :)

When I run the command:
docker run -d -p 5998:5002 flask_image

I receive the error:

docker: Error response from daemon: driver failed programming external connectivity on endpoint peaceful_ishizaka (04aaac09a8ed7ad7443ce6389a80f7559d70cdab46bf808da19202c02ce22489): fork/exec /home/afzal.patel/bin/rootlesskit-docker-proxy: no such file or directory.

Any suggestions?

Hi there again, I'm facing an error as usual trying docker compose. My error happens towards one of the last steps of Nginx when I try to run docker-compose -f docker-compose.prod.yml exec web python manage.py create_db.

The error I get is
ERROR: for e5c28d72220d_flask-on-docker_nginx_1 Cannot start service nginx: driver failed programming external connectivity on endpoint flask-on-docker_nginx_1 (6c37d4f69ec4ff84058a1945ee0a63df6d71c7d8d9d57bff9eb55531d13c8d6f): Error starting userland proxy: error while calling PortManager.AddPort(): listen tcp 0.0.0.0:1337: bind: address already in use

and

ERROR: for nginx Cannot start service nginx: driver failed programming external connectivity on endpoint flask-on-docker_nginx_1 (6c37d4f69ec4ff84058a1945ee0a63df6d71c7d8d9d57bff9eb55531d13c8d6f): Error starting userland proxy: error while calling PortManager.AddPort(): listen tcp 0.0.0.0:1337: bind: address already in use ERROR: Encountered errors while bringing up the project.

Thanks for everything!

Edit: Tried logging in again, it works now! Weird error

When I log in with the correct password, I get this error:

shell request failed on channel 2

I'm hoping I haven't catastrophically messed up, but I can't get onto the lambda server.

I'm attempting to do the lab for this week, but I've run into this error bash: cannot create temp file for here-document: Disk quota exceeded. Do you have any advice for how to clear some space up through the command line. (I'm unable to save anything I've edited in the files)

Thank you!

Note: Moved my issue here (copy pasted)

So I've ironed out some of the initial problems as mentioned by @mikeizbicki and ended up redoing the entire process and now have the correct export command in my .bashrc file. I've also made sure (again and again) that my docker files are not in bin but .local/bin. I've also followed Sam's suggestions and made sure my unit file was correct in ~/.config/systemd/user/docker.service

Now when I run systemctl --user start docker
I have no problems, but when I try to run docker run ubuntu
I get the following error:
Cannot connect to the Docker daemon at unix:///run/user/1137/docker.sock. Is the docker daemon running?
so usually I attempt systemctl --user daemon-reload
I think I got this error after moving my files from bin to .local/bin and I've reinstalled Docker at least 5 times (so maybe that's the problem?) I always assumed that my files were being rewritten each time they were moved. Thanks!

Edit: I've learned so much about docker commands and process after all of these issues, but I still can't get it to work xD

I couldn't clone the SQL folder for some odd reason (everything else I could pull from Github) so I ended up just copying over all the sql files--will this cause any errors, particularly for 05.sql? Alternatively, should I continue trying to clone the SQL folder? Thank you! :)

Happy Saturday!

I am having a consistent problem with the SQL homework where I am getting the exact expected output, however the test cases are not passing. For instance the problem in the screenshot below is number 15, and on the left is the output of my code inside the docker-container, and the right is the 15.out file. However, when I run docker-compose exec pg ./check_answers.sh, I am still getting sql/15.sql fail. I thought it may be not having the AS column names correctly but I even went through and verified that they are all correct, so I am not sure where to go from here.

Thanks for any advice, hope everyone is having a great weekend!

As mentioned today in class, all lectures will be recorded so you can watch them asynchronously. I'll be posting the recordings to a youtube playlist at:

https://www.youtube.com/playlist?list=PLSNWQVdrBwoYN0AqeD8iJDZoDiJE6IF6g

The first video has been uploaded.

After updating my Dockerfile to install netcat, I am trying to rebuild and run to test that it has al and I keep seeing the error below (first is in my terminal, and second is on my browser. I thought it was an issue with my ports, but I have confirmed those are all correct, so I'd love some guidance here. Thanks!

We went over extensively in class the importance of making sure .env.prod.db, where production credentials normally are, don't get into the git repo, and the tutorial for the lab/homework echoes that, but it also seems to suggest also putting .env.prod into .gitignore. Is that something we should be doing? In general, why would you want .env.prod not to be in version control? Is it just a preference thing like.env.dev, like you mentioned in class?

While attempting the first step of this week's lab, I am being unable to connect to https://localhost:8080 even after logging into the lambda server with port forwarding. Attached is a screenshot of what is happening. Please advise. Thank you!

I believe that the type CHAR in sql has typalign: c and typlen: 1, but when using the query from https://www.2ndquadrant.com/en/blog/on-rocks-and-sand/ I get that "b CHAR" from the "example" table actually is type "bpchar" has typalign: i and typlen: -1.

So is "b CHAR" from the "example" table a "char" type or a "bpchar" type?

Anyone else experiencing an immense lagging on the server? Or it's just from my end?

I have started to run map.py on all of the .zip files using nohup.
It seems to have worked when I first checked the running processes using 'ps'.
However, now when I login or try to use any command I am constantly receiving the message:

-bash: fork: retry: Resource temporarily unavailable

While trying to run docker-compose build, I keep getting the following error, I am not sure why I am getting a permission error, any help would be appreciated

Traceback (most recent call last): File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 601, in urlopen chunked=chunked) File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 357, in _make_request conn.request(method, url, **httplib_request_kw) File "/usr/lib/python3.6/http/client.py", line 1264, in request self._send_request(method, url, body, headers, encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1310, in _send_request self.endheaders(body, encode_chunked=encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1259, in endheaders self._send_output(message_body, encode_chunked=encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1038, in _send_output self.send(msg) File "/usr/lib/python3.6/http/client.py", line 976, in send self.connect() File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/transport/unixconn.py", line 43, in connect sock.connect(self.unix_socket) PermissionError: [Errno 13] Permission denied

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "/home/ASanchez21/.local/lib/python3.6/site-packages/requests/adapters.py", line 449, in send timeout=timeout File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 639, in urlopen _stacktrace=sys.exc_info()[2]) File "/usr/lib/python3/dist-packages/urllib3/util/retry.py", line 367, in increment raise six.reraise(type(error), error, _stacktrace) File "/usr/lib/python3/dist-packages/six.py", line 702, in reraise raise value.with_traceback(tb) File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 601, in urlopen chunked=chunked) File "/usr/lib/python3/dist-packages/urllib3/connectionpool.py", line 357, in _make_request conn.request(method, url, **httplib_request_kw) File "/usr/lib/python3.6/http/client.py", line 1264, in request self._send_request(method, url, body, headers, encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1310, in _send_request self.endheaders(body, encode_chunked=encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1259, in endheaders self._send_output(message_body, encode_chunked=encode_chunked) File "/usr/lib/python3.6/http/client.py", line 1038, in _send_output self.send(msg) File "/usr/lib/python3.6/http/client.py", line 976, in send self.connect() File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/transport/unixconn.py", line 43, in connect sock.connect(self.unix_socket) urllib3.exceptions.ProtocolError: ('Connection aborted.', PermissionError(13, 'Permission denied'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/api/client.py", line 214, in _retrieve_server_version return self.version(api_version=False)["ApiVersion"] File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/api/daemon.py", line 181, in version return self._result(self._get(url), json=True) File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/utils/decorators.py", line 46, in inner return f(self, *args, **kwargs) File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/api/client.py", line 237, in _get return self.get(url, **self._set_request_timeout(kwargs)) File "/home/ASanchez21/.local/lib/python3.6/site-packages/requests/sessions.py", line 555, in get return self.request('GET', url, **kwargs) File "/home/ASanchez21/.local/lib/python3.6/site-packages/requests/sessions.py", line 542, in request resp = self.send(prep, **send_kwargs) File "/home/ASanchez21/.local/lib/python3.6/site-packages/requests/sessions.py", line 655, in send r = adapter.send(request, **kwargs) File "/home/ASanchez21/.local/lib/python3.6/site-packages/requests/adapters.py", line 498, in send raise ConnectionError(err, request=request) requests.exceptions.ConnectionError: ('Connection aborted.', PermissionError(13, 'Permission denied'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "/home/ASanchez21/.local/bin/docker-compose", line 8, in <module> sys.exit(main()) File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/main.py", line 80, in main command_func() File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/main.py", line 189, in perform_command project = project_from_options('.', options) File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/command.py", line 70, in project_from_options enabled_profiles=get_profiles_from_options(options, environment) File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/command.py", line 153, in get_project verbose=verbose, version=api_version, context=context, environment=environment File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/docker_client.py", line 43, in get_client environment=environment, tls_version=get_tls_version(environment) File "/home/ASanchez21/.local/lib/python3.6/site-packages/compose/cli/docker_client.py", line 170, in docker_client client = APIClient(use_ssh_client=not use_paramiko_ssh, **kwargs) File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/api/client.py", line 197, in __init__ self._version = self._retrieve_server_version() File "/home/ASanchez21/.local/lib/python3.6/site-packages/docker/api/client.py", line 222, in _retrieve_server_version 'Error while fetching server API version: {0}'.format(e) docker.errors.DockerException: Error while fetching server API version: ('Connection aborted.', PermissionError(13, 'Permission denied'))

I've put together a short, anonymous survey that will help me determine how the class is going for everyone. Please take a minute to fill it out, and I'll use the results to improve the course for the remainder of the semester.

Link: https://docs.google.com/forms/d/1oD1a-pPWQz1GOf_B9_EKKBdVM8JjqRvPjrDcoOQS0JY

So, when I run the python file to input the data into the Normalized DB, it works perfectly for the first 9000 tweets; however, in the last 1000, I get the following error.

And this is not actually a problem with the source field as stated in the error as even if I get rid of it, the error persists. Is there something we are supposed to do to filter out these NULL characters? I have tried some things but none of them seem to be working. Thank you!

I was wondering if you might be able to help with the error I am getting with the Docker download, it is saying I do not have access to enough memory, and when I asked how much memory I have to the computer with, du -s, it says only 116M. Is there a certain file I should be storing to that has more memory?

lambda-server:~ $ curl -fsSL https://get.docker.com/rootless | sh

Installing stable version 20.10.3

% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 65.7M 100 65.7M 0 0 62.9M 0 0:00:01 0:00:01 --:--:-- 62.9M
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 19.0M 100 19.0M 0 0 48.9M 0 --:--:-- --:--:-- --:--:-- 48.9M
tar: dockerd: Wrote only 512 of 10240 bytes
tar: docker-init: Cannot write: Disk quota exceeded
tar: docker-proxy: Cannot write: Disk quota exceeded
tar: containerd-shim-runc-v2: Cannot write: Disk quota exceeded
tar: containerd-shim: Cannot write: Disk quota exceeded
tar: containerd: Cannot write: Disk quota exceeded
tar: Exiting with failure status due to previous errors

Hi! So, when I try to access the pagila-hw from the week3 directory it is giving me a 404 error at this link. However, the repo at https://github.com/mikeizbicki/pagila-hw works and I was wondering if this is the same as the one in the week3 folder. Thank you!

Hi I noticed that question 4 on this week's hw has a slight typo:

Use the count() aggregation function and the rental_price column of the film table.

rental_price should be rental_rate

Referring to your comment on closed issue #12 :

"docker is looking for the rootlesskit-docker-proxy program in your $HOME/bin folder, but I can see that you don't have this folder and have moved the executeables to $HOME/.local/bin. Somehow, you need to get docker to be able to find the this binary, either by adjusting your $PATH or moving the files."

I was searching how to change the path that docker uses to find rootlesskit-docker-proxy and the other necessary files that I moved to my .local/bin/ and was wondering if you could point me to a resource to do so. I believe as we were about to cover changing the path in our Friday lecture, we ran into the glitch that when you exited and logged back onto the server, docker still ran, so we did not end up changing the docker path to search for .local/bin. I recognize I could move my bin file back to the home directory to solve this, but am hoping to use the elegant solution. Thanks!

Hey everyone!
I was going through and doing the unix processes review, and I am having trouble killing my ./script.sh process after I ran it with the nohup command.

I have verified that it is running in the background by checking it with wc -l output2 and seeing that the number is increasing, but when I run ps -ef | grep Curtis.Salinger.22, I only see three processes as shown below in the image. When I kill the first it says not permitted, when I kill the second it says No such process, and when I kill the third it logs me out of the lambda server. So I am not sure how to find the PID of ./script.sh process to kill it.

Thanks for the guidance here!

Hello Mike and class,

I am running into issue in the final steps of my dockerizing project where I am able to get onto my website and get to the image upload page, however when I then try and go to view the image, I get a 404 error. I do not get an error output along the way so I am unsure where to go from here. My only irregularity is that when I run docker-compose down -v, I get the error shown below. Thanks for any guidance where to go from here!

In the development server when I upload an image or create a .txt file in the docker container, that same file does appear in the lambda server folder.

• I understand that this behavior is due to volumes in the docker-compose.yml file.

However, in the production server when I upload an image or create a .txt file in the docker container, that same file does not appear in the lambda server folder. I ran into this when trying to access images I uploaded while running the production server, after switching back to the development server.

• I see that the syntax is different in setting volumes in the docker-compose.prod.yml file. Is there a reason we do not want the same behavior as in the development server?

I am working my way through the tutorial (https://testdriven.io/blog/dockerizing-flask-with-postgres-gunicorn-and-nginx/) and am having an issue that I suspect I inadvertently caused somewhere along the way. After adding the create_db command to the CLI I am trying to build and spin u p. the two containers. I do this via:

docker-compose up -d --build
This seems to work successfully - the container is running - checked with docker ps - and the command exits with Starting flask-on-docker_web_1 ... done. However when I try to invoke the python function create_db through the command line via:
docker-compose exec web python manage.py create_db
an error is returned:
ERROR: No container found for web_1
I've done a bit of stack overflow searching and it seems like most of the time this happens for people it is because the container was never brought up in the first place, but I am reasonably confident that I have the container in question up. Any help about how to fix this would be much appreciated!

A few good questions came up in lab today in lab that I'll share with everyone.

About the denormalized database:

1. The COPY command we did in class should pass all the test cases for the denormalized db. If it's not passing, you probably ran the command multiple times, and inserted duplicate data. You'll need to delete the volume and rerun the command to get it to pass.

About how to insert data into the normalized database:

1. For the geo column of the normalized database, you can just insert a NULL value same as is used in the denormalized version of the database. My solution actually computes a GPS coordinate using the command ST_GeomFromText(:geo_str || '(' || :geo_coords || ')'), but none of the test cases use the GPS coordinate, so you don't have to do that.

2. Not every tweet will have every field being inserted into the table. For example, not every tweet has a retweet_count. You still have to insert something into the table for these fields, though, and a NULL value is perfectly appropriate. The .get method of python dictionaries can be helpful here since it lets you provide a default value for when the key is not present. For example, I got the retweet_count using the command tweet.get('retweet_count',None).

Hello,

I have followed the instructions on https://runnable.com/docker/python/dockerize-your-flask-application but when it comes to the section running the image, when I try to do the command docker build -t flask-tutorial:latest . it says permission denied while trying to connect to the Docker daemon.

Note: Fixed it, was a tabbing issue

I'm on the very last step of the Production Dockerfile section and ran docker-compose -f docker-compose.prod.yml down -v and I get the following issue:
ERROR: The Compose file './docker-compose.prod.yml' is invalid because: Unsupported config option for services.web: 'dockerfile'
This seems like a fairly straightforward issue but I don't see anything wrong with my Compose file.

I also followed the suggestions about fixing the Dockerfile from Issue #20 as suggested in the previous question. Any suggestions would be appreciated. Thank you!

when running
docker-compose -f docker-compose.prod.yml up -d --build
I ran into the following error.

./project/__init__.py:52:12: F541 f-string is missing placeholders
The command '/bin/sh -c flake8 --ignore=E501,F401 .' returned a non-zero code: 1
ERROR: Service 'web' failed to build

This appears to be coming from __init__.py line 52

 46 @app.route("/upload", methods=["GET", "POST"])
 47 def upload_file():
 48     if request.method == "POST":
 49         file = request.files["file"]
 50         filename = secure_filename(file.filename)
 51         file.save(os.path.join(app.config["MEDIA_FOLDER"], filename))
 52     return f"""
 53     <!doctype html>
 54     <title>upload new File</title>
 55     <form action="" method=post enctype=multipart/form-data>
 56       <p><input type=file name=file><input type=submit value=Upload>
 57     </form>
 58     """

I tried commenting out this code from the file and and the command above ran without problem. Any suggestions?

I am working through the "dockerizing *" tutorial, and after making the necessary directories and doing python manage.py run, the server launches correctly and I see running on http://127.0.0.1:5000/ but when I go to that in my browser, I am prompted with the error shown below. The only difference I can find is that I could not get $python3.8 -m venv env to run, so I tried python3 -m venv env which seemed to be successful but may be the cause of my problem, so I am unsure what to do from here.

Thanks for the help!

GitHub actions is currently experiencing an outage, and so homeworks submitted will not be able to run the CI checks.

To submit your assignments, please wait until GitHub Actions is back online so that you can get the test cases to run. These sort of outages are usually short (few hours max), but no one will experience a late penalty who is affected by this.

See https://www.githubstatus.com/ for details about the issues.

I'm running docker-compose -f docker-compose.prod.yml exec web python manage.py create_db and it's working up until step 9 with flake8. I tried the suggestions from Issue #20 but I'm still having problems. I'm getting The command '/bin/sh -c flake8 --ignore=E501,F401 .' returned a non-zero code: 1 ERROR: Service 'web' failed to build

Any suggestions? Thanks :)

I'm having an issue where when I run check_answers.sh on the lambda server, all the tests pass, but when I push to GitHub the tests workflow fails. When I check the workflow results, it appears like everything is running properly, but when check_answers.sh is running in the workflow, the test for just sql/04.sql fails, and I have no idea why this would be the case.

1. Many students during lab were getting error messages when running the command

   $ python3 manage.py run
   

   This is because that command launches flask, which attempts to bind to port 5000 on the lambda server. Only a single program can be bound to that port at any given time, and I already have a program running on that port. You can either safely ignore this and continue with the lab, or use the --port command line argument to change the port to a different number.

2. The Dockerfile.prod used in the lab is based off of the docker image python:3.8.1-slim-buster which has been updated since the webpage was created. This update unfortunately changed the behavior of how the addgroup and adduser commands work. These commands are called in Dockerfile.prod, and the syntax is now broken. I've uploaded a fixed file to the course github repo at https://github.com/mikeizbicki/cmc-csci143/blob/2021spring/week_02/Dockerfile.prod

I am having issues port forwarding in Putty since I am using Windows. I believe I added the correct information to establish the ssh tunnel but when I try opening a connection, I get this error.

There are a lot of hard homeworks in this class, and so to help you out with these homeworks I want to set aside some dedicated "lab" time each week. Attending these labs will not be required, however, it will be a chance to work on the homework problems together with other students in a structured way and have dedicated help from me. Also, if you attend the lab on any given week, you will get a 2-day extension on that week's homework assignment.

Please complete the following survey about times that you'd be available for these labs: https://www.when2meet.com/?10814642-efjpn The times are all in Claremont time, and some of them are quite early/late in order to accommodate students in other timezones.

Welcome to big data!

In this thread, we'll all introduce ourselves and practice using github issues. We'll be using github issues for all our in-class communication, so it's important that you understand how the system works. In particular, you need to understand github's markdown formatting syntax.

To practice, please reply to this post with:

1. your name (including what you'd like me to call you if it's different than in sakai)
2. your favorite food highlighted in bold and
3. a quote you like placed inside a code block

Due to daylight savings time, the clocks in Claremont are 1 hour faster than they used to be. Depending on your timezone, this may mean that class will start 1 hour earlier for you this week.

Dealing with timezones are one of the very common mistakes that programmers make. In SQL, the short answer is that you should always use the TIMESTAMPTZ (same as TIMESTAMP WITH TIMEZONE type to store timestamps. To understand some of the difficulties that these types will handle for you automatically, see these two videos:

1. The Problem with Time & Timezones - Computerphile
2. Why Leap Seconds Cause Glitches - Computerphile
3. End of Time (Unix) - Numberphile

On the Production Dockerfile part of the tutorial I'm getting the following error
The command '/bin/sh -c addgroup -S app && adduser -S app -G app' returned a non-zero code: 1 ERROR: Service 'web' failed to build

I'm getting the error when I build docker-compose.prod.yml and I'm almost certain that the error comes from Dockerfile.prod line 41 with
# create the app user
RUN addgroup -S app && adduser -S app -G app

Is anyone else running into this error?

As I mentioned in lecture, the homework that's posted this week won't be due this week. Instead, you'll have until next week Sunday (Feb 28). We've covered the material for completing the first half of the questions, and we'll cover the rest of the material next week on Monday.

I'll still be available during the lab time this week on Friday to answer any questions.