I would like to be able to do something similar to this is PowerShell
docker logs -f my-container | grep -q "string-to-match"
i.e. to follow a log file and when a string is matched you stop follow the file. My idea was to try something like this
docker logs -f my-container | Select-String "string-to-match".
I know it's not complete but I can't figure out how to make it work. I also did try to use WSL2 like this
docker logs -f my-container | wsl grep -q "string-to-match".
but it keeps following the log even after a match has been found!
A WSL-solution would solve my problem but a native PowerShell-solution would be preferable!
I tried with ugrep.exe in PowerShell:
docker logs -f my-container | ugrep -q "string-to-match"
and that appears to work fine as it stops at the first match. This can also be done with ugrep -m1 "string-to-match" to report the line that matched, since -m1 stops searching further after the first hit.
Related
I would like to use awk in gitlab-ci.yml to kill a docker container. However, awk does not work as expected.
For example, I want to kill a docker container called ADockerContainer using awk. Therefore I use the following command:
docker kill $(docker ps | grep ADockerContainer | awk '{print $1}')
After the execution of the command, I get:
"docker kill" requires at least 1 argument.
Does anyone know how to fix this?
docker kill (and other commands) will take the container name directly, so you don't need any sort of command substitution here. It's enough to run
docker kill AContainerName
I'm running the command docker logs <container-id> | tail -10 and still, docker shows the entire log history. I know docker logs --tail 10 <container-id> is a valid command and serves the purpose. But, why doesn't the former command works as it does in case of a file?
If you want your everything your program writes to either stdout or stderr to go through the pipeline to tail, redirect stderr to stdout:
docker logs "$container_id" 2>&1 | tail -10
in case someone may want to tail -f docker logs
here you may try this:
docker logs -f --tail 0 "$container_id"
docker ps sorts by time, but the most recent docker instance is at the very top. This means if you started very many instances you have to scroll all the way to the top to see them. How do we output "docker ps -a" in reverse order, so that the most recent instance is printed at the bottom?
You can pipe the output to tac[1] like:
docker ps -a | tac
[1] From man tac: tac - concatenate and print files in reverse
Latest created container:
docker ps -a -l
Latest 5 created containers:
docker ps -a -n 5
As far as I know ordering is not possible but maybe you don't really need it...
It's enough to get what you want.
$ docker ps -a --format "table {{.ID}}\t{{.Names}}\t{{.CreatedAt}}" | (read -r; printf "%s\n" "$REPLY"; sort -k 3 -r )
See also
How to sort or order results docker ps --format?
I'm currently working with docker config files and I'm looking for a way to automate the removal of 'old' config file. I use a script that will update all my config files version with +1;
app1-config-file-1.2.1
app1-config-file-1.2.2
app1-config-file-1.2.3
etc etc.
Now I would like to remove app1-config-file-1.2.2 when app1-config-file-1.2.3 is created.
This command gets me kinda close;
docker config rm $(docker config ls | grep -e 'app1'.*'-1.2.2')
Where 'app1' is the prefix and the '-1.2.2', well, is the version I want to remove.
The thing is that the command above does remove the correct config, but it will also try to remove the following 'configs'
Error response from daemon: access denied
Error: No such config: hours
Error: No such config: ago
Error response from daemon: access denied
Error: No such config: hours
Error: No such config: ago
Which is what comes back from my query:
$(docker config ls | grep -e 'app1'.*'-1.2.2')
I tried adding the --quiet or -q to only get back the config IDs. But for some reason I can't use it with config files the way it works with container.
docker config ls -q | grep -e 'app1'.*'-1.2.2'
results in nothing.
docker config ls | grep -e 'app1'.*'-1.2.2'
results in a list with ID, configfile names, age etc. Basically all the config files I would like to remove, but I just need the ID's
So my question is,
What is the correct way to get the IDs of specific docker config file while using wildcards?
Thank you
When you write
docker config rm $(docker config ls | grep -e 'app1'.*'-1.2.2')
This does three things:
Run docker config ls, producing its formatted output.
Filter (grep) that output to only lines that contain app1...-1.2.2.
Pass the resulting output, split into words, as arguments to docker config rm.
The ... | grep invocation is "dumb" in the sense that it doesn't know anything in particular about the input it has, it just knows that it's lines of text and it should try to filter it.
The better option here is to more directly tell docker config ls what you're looking for. That command takes a --filter option; that's somewhat underdocumented, but if you know the exact name of the config object, you can combine it with --quiet to tell Docker (not the shell) to first filter to a specific config object then only print out its ID.
docker config rm $(docker config ls -f name=app1-config-file-1.2.2 -q)
# But really this is the same as
docker config rm app1-config-file-1.2.2
The "shellier" way is to use another tool to clean up the formatted output. The examples in the Docker documentation show the config ID as the first whitespace-separated column, so you could use awk(1) like
docker config ls | \
grep 'app1.*-1.2.2' | \
awk '{ print $1 }' \
xargs docker config rm
(Other tools work fine here too; personally I'd use sed(1) but it's harder to explain in an SO answer.)
I read my Docker container log output using
docker logs -f <container_name>
I log lots of data to the log in my node.js app via calls to console.log(). I need to clean the log, because it's gotten too long and the docker logs command first runs through the existing lines of the log before getting to the end. How do I clean it to make it short again? I'd like to see a command like:
docker logs clean <container_name>
But it doesn't seem to exist.
First, if you just need to see less output, you can have docker only show you the more recent lines:
docker logs --since 30s -f <container_name_or_id>
Or you can put a number of lines to limit:
docker logs --tail 20 -f <container_name_or_id>
To delete the logs on a Docker for Linux install, you can run the following for a single container:
echo "" > $(docker inspect --format='{{.LogPath}}' <container_name_or_id>)
Note that this requires root, and I do not recommend this. You could potentially corrupt the logfile if you null the file in the middle of docker writing a log to the same file. Instead you should configure docker to rotate the logs.
Lastly, you can configure docker to automatically rotate logs with the following in an /etc/docker/daemon.json file:
{
"log-driver": "json-file",
"log-opts": {"max-size": "10m", "max-file": "3"}
}
That allows docker to keep up to 3 log files per container, with each file limited to 10 megs (so a limit between 20 and 30 megs of logs per container). You will need to run a systemctl reload docker to apply those changes. And these changes are the defaults for any newly created container, they do not apply to already created containers. You will need to remove and recreate any existing containers to have these settings apply.
The best script I found is
sudo sh -c 'truncate -s 0 /var/lib/docker/containers/*/*-json.log'
It cleans all logs and you don't need to stop the containers.
Credit goes to https://bytefreaks.net/applications/docker/horrible-solution-how-to-delete-all-docker-logs
If you want to remove all log files, not only for a specific container's log, you can use:
docker system prune
But, note that this does not clear logs for running containers.
This is not the ideal solution, but until Docker builds in a command to do it, this is a good workaround.
Create a script file docker-clean-logs.sh with this content:
#!/bin/bash
rm $(docker inspect $1 | grep -G '"LogPath": "*"' | sed -e 's/.*"LogPath": "//g' | sed -e 's/",//g');
Grant the execute permission to it:
chmod +x ./docker-clean-logs.sh
Stop the Docker container that you want to clean:
docker stop <container_name>
Then run the above script:
./docker-clean-logs.sh <container_name>
And finally run your container again:
docker start ...
Credit goes to the user sgarbesi on this page: https://github.com/docker/compose/issues/1083
You can use logrotate as explained in this article
https://sandro-keil.de/blog/2015/03/11/logrotate-for-docker-container/
This needs to be done before launching the container.
Run:
docker inspect {containerId}
Copy LogPath value
truncate -s 0 {LogaPath}
Solution for a docker swarm service:
logging:
options:
max-size: "10m"
max-file: "10"
In order to do this on OSX, you need to get to the virtual machine the Docker containers are running in.
You can use the walkerlee/nsenter image to run commands inside the VM like so:
docker run --rm -it --privileged --pid=host walkerlee/nsenter -t 1 -m -u -i -n sh
Combining that with a simplified version of the accepted answer you get:
#!/bin/sh
docker run --rm -it --privileged --pid=host walkerlee/nsenter -t 1 -m -u -i -n \
cp /dev/null $(docker inspect -f '{{.LogPath}}' $1)
Save it, chmod +x it, run it.
As far as I can tell this doesn't require the container to be stopped. Also, it clears out the log file (instead of deleting it) avoiding errors when doing docker logs right after cleanup.
On Windows 10 none of the solutions worked for me, I kept getting 'No such file or directory'
This worked
Get container ID (inspect the container)
In file explorer open docker-desktop-data (in WSL)
Navigate to version-pack-data\community\docker\containers\CONTAINER_ID
Stop the container
Open the file CONTAINER_ID-json.log file and trim it or just create a blank file with same name
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