Initial commit

.env

@@ -0,0 +1,12 @@
+# ==============================================================================
+# About the project
+# ------------------------------------------------------------------------------
+# Note: this variables will be used as replace strings in `docker-compose.yml`.
+# They are NOT environment variables passed to the containers. 
+# Those variables are set in the *.env files under the config folder.
+# Check ./docs/ENVIRONMENT_VARIABLES.md and ./docs/VOLUMES.md to understand 
+#   the usage of these strings.
+
+# Environment to use
+ENVIRONMENT=dev
+# ==============================================================================

.gitignore

@@ -0,0 +1,4 @@
+pre/*.env
+pro/*.env
+pre/*-crontab
+pro/*-crontab

Dockerfile

@@ -0,0 +1,19 @@
+FROM python:3.10-alpine
+
+RUN apk update
+
+# Setting a default crontab for the service
+COPY config/dev/cron.d/service-crontab /etc/cron.d/service-crontab
+
+RUN chmod 0644 /etc/cron.d/service-crontab &&\
+    crontab /etc/cron.d/service-crontab
+
+# Fixing Python deps
+ADD requirements.txt /tmp/requirements.txt
+RUN pip install -r /tmp/requirements.txt
+
+# Adding the app itself
+RUN mkdir /data
+ADD app /app
+WORKDIR /app
+ENTRYPOINT ["sh", "-c" , "crond -f"]

README.md

@@ -0,0 +1,192 @@
+# Template Iron: A template for easy-to-deploy dockerized containers
+
+A Docker Compose template container conceived to easily share applications with a smart management of environments.
+This project is thought to ease the process of deploying scripts and solutions which need to have some dependencies and environment settings defined in before hand.
+
+The default functionality of the container is limited to trying to logging the public IP address of the container. 
+This task is performed, by default, each and every minute as defined in the `crontab` file to illustrate the approach.
+
+## License
+
+This software is licensed using GPLv3. Check the [`COPYING`](COPYING) file for further details.
+
+## Dependencies
+
+Check that you have Docker and Docker Compose installed in your computer.
+Specfic instructions to do so in your OS can be found in the official docs for Docker ([here](https://docs.docker.com/get-docker/)) and Docker Compose ([here](https://docs.docker.com/compose/install/)).
+
+Once installed, you can check the versions using the following commands:
+
+```
+$ docker --version
+Docker version 18.09.0, build 4d60db4
+$ docker-compose --version
+docker-compose version 1.23.1, build b02f1306
+```
+
+For convenience, the `Dockerfile` will deal with the Python dependencies at building time using `pip`, but any other additional dependencies and images can be used here.
+In this case, it is a simple as installing the dependencies set in the `requirements.txt` file.
+Add in this file any other dependencies that you may need.
+
+## Quick Start
+
+First of all, clone the repository and then, fill in the `.env` file with the environment variables pointing the environment variables files to the appropriate `config/pro/` folder or the `config/dev` one depending on your current environment.
+By default, the `config/dev` samples will be loaded.
+Note that some files in the config folder are deliberately not copied in the Git repository.
+
+To start everything, use:
+
+```
+$ docker-compose up 
+```
+
+Note that if you make changes and you want to see them you will need the `--build` option:
+
+```
+$ docker-compose up --build
+Building main_service
+Step 1/10 : FROM python:3.10-alpine
+ ---> 482b8fa3563e
+Step 2/10 : RUN apk update
+ ---> Using cache
+ ---> 39bccfa17f0d
+Step 3/10 : COPY config/dev/cron.d/service-crontab /etc/cron.d/service-crontab
+ ---> Using cache
+ ---> 11b24ce1300a
+Step 4/10 : RUN chmod 0644 /etc/cron.d/service-crontab &&    crontab /etc/cron.d/service-crontab
+ ---> Using cache
+ ---> 5d5a0e2a504c
+Step 5/10 : ADD requirements.txt /tmp/requirements.txt
+ ---> Using cache
+ ---> d8e86d8bba81
+Step 6/10 : RUN pip install -r /tmp/requirements.txt
+ ---> Using cache
+ ---> 2e4742159266
+Step 7/10 : RUN mkdir /data
+ ---> Using cache
+ ---> 40b54851e289
+Step 8/10 : ADD app /app
+ ---> 93e29a3a9aa6
+Step 9/10 : WORKDIR /app
+ ---> Running in 08a379190249
+Removing intermediate container 08a379190249
+ ---> 2c703d06f589
+Step 10/10 : ENTRYPOINT ["sh", "-c" , "crond -f"]
+ ---> Running in ad51f1e83a7d
+Removing intermediate container ad51f1e83a7d
+ ---> 425bae76ea02
+
+Successfully built 425bae76ea02
+Successfully tagged temperediron_main_service:latest
+Recreating temperediron_main_service_1 ... 
+Recreating temperediron_main_service_1 ... done
+Attaching to temperediron_main_service_1
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:45:00,779 | Checking the public IP…
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:45:00,781 | Starting new HTTPS connection (1): ifconfig.me:443
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:45:01,040 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:45:01,041 | My public IP is: XX.XX.XX.XX
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:45:01,041 | Closing the application…
+```
+
+Once started, the deployed container will start a cron service to run schedule tasks.
+In this context, the scheduled task is as simple as grabbing the public IP address and logging it both, in the terminal and in a specific log file under `/log` in the container.
+
+## Additional Docker and Docker Compose Tips
+
+To stop the containers, you can always use `docker-compose down` from the project home.
+At the same time, to reraise without building, use `docker-compose up`.
+Note that this approach will show the output in the terminal.
+However, running this in detached mode can be useful.
+
+```
+$ docker-compose up -d
+```
+
+To grab the logs of a specifc container set up using `docker-compose` you can use a specific command: `docker-compose logs <service_name>` as follows:
+
+```
+$ docker-compose logs
+Attaching to temperediron_main_service_1
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:45:00,779 | Checking the public IP…
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:45:00,781 | Starting new HTTPS connection (1): ifconfig.me:443
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:45:01,040 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+...
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:52:00,738 | Starting new HTTPS connection (1): ifconfig.me:443
+main_service_1  | [DEBUG] tempered_iron @ 2022-04-05 15:52:00,962 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:52:00,964 | My public IP is: XX.XX.XX.XX
+main_service_1  | [INFO] tempered_iron @ 2022-04-05 15:52:00,964 | Closing the application…
+```
+
+With this approach, the application will end a return to the prompt.
+However, if you prefer to _follow_ the logs, you can use the `-f` or `--follow` as shown with `docker-compose logs --help` so as to let the application wait for new lines:
+
+```
+$ docker-compose logs --help
+View output from containers.
+
+Usage: logs [options] [SERVICE...]
+
+Options:
+    --no-color          Produce monochrome output.
+    -f, --follow        Follow log output.
+    -t, --timestamps    Show timestamps.
+    --tail="all"        Number of lines to show from the end of the logs
+                        for each container.
+$ docker-compose logs -f
+```
+
+Note that for debugging purposes you might find useful to enter the container using a shell.
+This can be done using `docker exec -it` command once you know the name of the container.
+In the aformentioned case, you can see in that the ID of the container is `425bae76ea02` from the output.
+
+If you have already run the container, you can check the running ones using `docker ps` to get the ID of the container you want to enter.
+
+```
+$ docker ps
+CONTAINER ID   IMAGE                       COMMAND                  CREATED         STATUS         PORTS     NAMES
+cf5d42a2da7d   temperediron_main_service   "sh -c 'crond -f' sh…"   2 minutes ago   Up 2 minutes             temperediron_main_service_1
+```
+
+In this case, entering the container is as simple as entering the container with a shell in interactive mode (`-it`).
+Note that the default shell of Alpine containers is `sh`, but use `bash` if it is available in the Docker image you used as a base image.
+
+```
+$ docker exec -it cf5d42a2da7d sh
+/app # ls
+run.py
+/app # python3 run.py 
+[INFO] tempered_iron @ 2022-04-05 15:49:08,761 | Checking the public IP…
+[DEBUG] tempered_iron @ 2022-04-05 15:49:08,763 | Starting new HTTPS connection (1): ifconfig.me:443
+[DEBUG] tempered_iron @ 2022-04-05 15:49:08,928 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+[INFO] tempered_iron @ 2022-04-05 15:49:08,930 | My public IP is: XX.XX.XX.XX
+[INFO] tempered_iron @ 2022-04-05 15:49:08,930 | Closing the application…
+/app # cd /log/
+/log # ls
+tempered_iron.log
+/log # tail -n 10 tempered_iron.log 
+[INFO] tempered_iron @ 2022-04-05 15:49:00,727 | Checking the public IP…
+[DEBUG] tempered_iron @ 2022-04-05 15:49:00,729 | Starting new HTTPS connection (1): ifconfig.me:443
+[DEBUG] tempered_iron @ 2022-04-05 15:49:00,940 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+[INFO] tempered_iron @ 2022-04-05 15:49:00,942 | My public IP is: XX.XX.XX.XX
+[INFO] tempered_iron @ 2022-04-05 15:49:00,942 | Closing the application…
+[INFO] tempered_iron @ 2022-04-05 15:49:08,761 | Checking the public IP…
+[DEBUG] tempered_iron @ 2022-04-05 15:49:08,763 | Starting new HTTPS connection (1): ifconfig.me:443
+[DEBUG] tempered_iron @ 2022-04-05 15:49:08,928 | https://ifconfig.me:443 "GET / HTTP/1.1" 200 14
+[INFO] tempered_iron @ 2022-04-05 15:49:08,930 | My public IP is: XX.XX.XX.XX
+[INFO] tempered_iron @ 2022-04-05 15:49:08,930 | Closing the application…
+```
+
+
+## Additional Tuning
+
+The environment sets up a default behaviour that automates a scheduled task at different times depending on the environment.
+Note that during the build process a service-crontab is added to the `/etc/crontab.d/` folder. 
+This file is then mounted in the `docker-compose.yml` file so as to use the provided configuration defined in the `dev`, `pre` or `pro` environment.
+This is done by the following lines in the `docker-compose.yml`.
+This means that if the frequency is expected to be changed in any of the environments, this has to be set.
+Follow the instructions on [`./PRODUCTION_RECOMMENDATIONS.md](./docs/PRODUCTION_RECOMMENDATIONS.md) to set this.
+
+Note that you can find more information about the project in the [`./ENVIRONMENT_VARIABLES`](./docs/ENVIRONMENT_VARIABLES.md) with more information about how to work with environment variables.
+At the same time in the [`./VOLUME_MANAGEMENT.md`](./docs/VOLUME_MANAGEMENT.md) you can find more information about how volumes are used.
+
+

app/run.py

@@ -0,0 +1,33 @@
+import logging
+import os
+import requests
+import sys
+
+
+# Grabbing environment variables
+LOGGER_NAME = os.environ.get("LOGGER_NAME", "Default App Logger")
+LOG_LEVEL = os.environ.get("LOG_LEVEL", "INFO")
+
+logging.basicConfig(
+    level=LOG_LEVEL,
+    format=f"[%(levelname)s] {LOGGER_NAME} @ %(asctime)s | %(message)s",
+    handlers=[
+        logging.FileHandler(f'/log/{LOGGER_NAME}.log'),
+        logging.StreamHandler()
+    ]
+)
+
+
+def main():
+    logging.info("Checking the public IP…")
+    try:
+        my_public_ip = requests.get("https://ifconfig.me").text
+        logging.info(f"My public IP is: {my_public_ip}")
+    except Exception as _:
+        logging.error("Something happened when grabbing the public IP. Details: {_}. Closing…")
+        sys.exit(-1)
+    logging.info("Closing the application…")
+
+
+if __name__ == "__main__":
+    main()

config/dev/cron.d/service-crontab

@@ -0,0 +1,25 @@
+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+* * * * * python3 /app/run.py
+
+

config/dev/service_variables.env

@@ -0,0 +1,4 @@
+# The name of the logger to be used. Typically, the name of the app, but not required.
+LOGGER_NAME=tempered_iron
+# One of: DEBUG, INFO, WARNING, ERROR
+LOG_LEVEL=DEBUG

config/pre/cron.d/service-crontab

@@ -0,0 +1,25 @@
+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+0 * * * * python3 /app/run.py
+
+

config/pre/cron.d/service-crontab.template

@@ -0,0 +1,25 @@
+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+0 * * * * python3 /app/run.py
+
+

config/pre/service_variables.env

@@ -0,0 +1,4 @@
+# The name of the logger to be used. Typically, the name of the app, but not required.
+LOGGER_NAME=tempered_iron
+# One of: DEBUG, INFO, WARNING, ERROR
+LOG_LEVEL=INFO

config/pre/service_variables.env.template

@@ -0,0 +1,4 @@
+# The name of the logger to be used. Typically, the name of the app, but not required.
+LOGGER_NAME=tempered_iron
+# One of: DEBUG, INFO, WARNING, ERROR
+LOG_LEVEL=WARNING

config/pro/cron.d/service-crontab.template

@@ -0,0 +1,25 @@
+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+0 * * * * python3 /app/run.py
+
+

config/pro/service_variables.env.templatae

@@ -0,0 +1,4 @@
+# The name of the logger to be used. Typically, the name of the app, but not required.
+LOGGER_NAME=tempered_iron
+# One of: DEBUG, INFO, WARNING, ERROR
+LOG_LEVEL=ERROR