I'm working on a Django REST framework API that is built in a docker image and launched/managed with docker-compose. When I launch my app I get the real time log of the Django application in the terminal. I accidentally closed the terminal and I want to re-establish a real time log output in the terminal without restarting my containers.
I tried docker-compose logs which will print a tail of the log but does not re-establish a real time output. I would have to rerun this every time I wanted to see new log information.
I think if you add the --follow flag to your command, you'll get the desired result. So:
docker-compose logs --follow ...
Related
Using Postgres 9.5 and the libpqxx c++ bindings, I want to launch a copy of postgres that is not installed on the users machine, but is instead packaged up in my application directory.
Currently, I am using pg_ctl.exe to start and stop the server, however when we do this, pg_ctl.exe seems to launch postgres.exe in a new terminal window.
I want it to launch postgres.exe in a headless state, but can't work out how.
I have tried enabling/disabling the logging collector, setting the logging method to a csv file (instead of stdout/stderr), and a couple of other logging related things, but I don't think the issue is the logging.
I have also tried running postgres.exe manually (without pg_ctl) and can get that to run headless by spawning it as a background process and redirecting the logs, but I would prefer to use the "pg_ctl start" api for the "wait for startup" (-w), and "timeout" (-t) options that it provides.
I believe you won't be able to do that with pg_ctl.
It is perfectly fine to start PostgreSQL directly through the server executable postgres.exe. Alternatively, you can use pg_ctl register to create a service and start the service.
In my use case, I was able to resolve the issue by running pg_ctl.exe using
CreateProcess, and providing the dwCreationFlags CREATE_NEW_PROCESS_GROUP | CREATE_NO_WINDOW.
I was originally using CREATE_NEW_PROCESS_GROUP | DETACHED_PROCESS, but DETACHED_PROCESS still allowed a postgres terminal to appear. This is because DETACHED_PROCESS will spawn the pg_ctl without a console, but any process that inherits stdin/stdout from pg_ctl will try to use it's console, and since there isn't one, one will be spawned. CREATE_NO_WINDOW however will launch the process with a conhost.exe, however the console will have no window. When the executables spawned by pg_ctl try to write to the terminal, they will successfully write to the console created by the conhost.exe which has no window.
I am now able to run pg_ctl from code with no console appearing.
I am using docker-compose for a development project. I have 6 services defined in my docker compose file. I have been using the below script to rebuild the images whenever I make a change.
#!/bin/bash
# file: rebuild.sh
docker-compose down
docker-compose build
docker-compose up
I am looking for a way to reduce the build time as building and restarting all the services seems unnecessary as I am usually only changing one module. I see in the docker-compose docs you can run commands for individual services by specifying the service name after e.g. docker-compose build myservice.
In another terminal window I tried docker-compose build myservice && docker-compose restart myservice while leaving the other ./rebuild.sh command open in the original terminal. In the ./rebuild.sh terminal window I see all the initialization messages being reprinted to the stdout so I know it is restarting that service but the code changes aren't there. What am I doing wrong? I just want to rebuild and restart a single service.
Try:
docker-compose up -d --force-recreate --build myservice
Note that:
-d is for Detached mode,
-force-recreate will recreate containers even is your code did not change,
-build is for build your images before starting containers.
At least the name of your service.
Take a look here.
I have an akka-scala app that I'm able to build as a jar. I can then send the jar to a remote server via Jenkins. However, I don't know how to properly deploy the app.
The first problem is killing previous instances of my app. If in Jenkins I try to execute such commands as pkill -f %proc% or ps ax | grep ... | awk ... | xargs kill -9 via ssh, Jenkins finishes with return code -1 even if I add || true to the end of these commands.
The second problem is starting the app. I'm able to successfully run the jar with nohup java -jar ... & command, but it doesn't really start though I'm able to see it in the process list.
None of these problems occur if I execute commands manually (even via ssh).
My question is - what am I doing wrong? What is the proper way to perform such task? Am I using the wrong tool?
Consider using something like supervisord for starting/stoping your app and also restarting it in case of crash or server reboot.
I tried to restart Postgres in Docker using 'docker restart ' command. It got stopped but I'm not able to start it. When I run the command 'ps -a' it says the status as 'Exited'. Is there any way to start it again? I don't want to loose any data in that database.
The container had one active connection during restarting. Is that creating a problem?
If the container crashed due to a bug or something, you may not be able to restart it. However, you should still be able to recover at least part of your data by making a new image out of the container that you want to recover. Here's how you do it:
First, list all the containers that have run in your machine:
docker ps -a
Find out which one is the container that run with all the data you want to recover. You should be able to figure out from the CREATED field (you know when you started it).
Grab the hash (CONTAINER_ID) of the container, and execute the following command:
docker commit <hash> <a_new_name:tag>
This will save the container as an image that you can execute.
Execute the container with a bash or sh session, depending on what our base image offers:
docker run --entrypoint sh/bash -it <a_new_name:tag>
This will give you access to the state of the container at the time of exiting, which will allow you to inspect its conditions, find bugs, and possibly recover some data. Good luck!
I am using Mirth connect which uses install4j to launch the program.
I am using the mcservice program and would like to get the pid of the launched application so that I can monitor it. How do I do this? Right now the service only has the standard start, status, etc commands.
Back in 2011 there seemed to be some indication that pid monitoring would be coming soon: http://www.mirthcorp.com/community/forums/showthread.php?t=5509
If you need get the the number of the process pid, you can do it by the terminal command:
$ pgrep mcservice
Also, you can store the pid number into a file and run the next command:
$ kill -9 `cat /path/to/file.pid`
In this case, you choosing the best solution for your issue. If you need something more complex you can view this link: Simple Process Checker To Find Out If A Service Is Running or Not