Newbie; I'm learning the Linux cmd line and one of my questions is; "inside the ‘stream-redirection’ folder there is a program called ‘program’. When you run this it will output to stdout and stderr. What is the stdout output??? I'm unsure how to read the output and even where it is??
I've tried
./program 1> stdout then cat stdout
I'm lost and I have to do the same with stderr.
Related
I am trying to use tee to log into two locations:
file in persistent storage
Docker stdout
Error log line from VirtualHost config:
ErrorLog "|/usr/bin/tee -a /var/log/apache/error.log /proc/1/fd/1"
Now the problem is that errors are logged twice in /proc/1/fd/1 (as docker logs states), yet error is only logged once into /var/log/apache/error.log
I´ve also tried run from cli:
echo 123 | /usr/bin/tee -a /tmp/test /proc/1/fd/1
This succesfully writes only once to both file and stdout.
Is there some reason why Apache logs writes twice to /proc/1/fd/1 while it logs only once to file and /usr/bin/tee also works as expected?
I set my /etc/docker/daemon.json to send container logs to GCP:
{
"log-driver": "gcplogs",
"log-opts": {
"gcp-meta-name": "some-cool-name",
"gcp-project": "some-project-name"
}
}
This works fine, but it seems there is no distinction between STDERR and STDOUT, both entries have a Severity of 'Default'
In container:
root#0bbcf70a30ed:/var/www/app# echo 'xx' > /proc/1/fd/2
root#0bbcf70a30ed:/var/www/app# echo 'xx' > /proc/1/fd/1
In GCP:
Is there anything I can do to make the logs from STDERR have a Severity of 'Error' ?
And if not, is there anything I can do to make all STDERR entries have a string like 'ERROR' prepended, so I can at least filter on them?
For example, in my Dockerfile I do:
RUN touch /var/log/apache2/error.log
RUN ln -sf /proc/1/fd/2 /var/log/apache2/error.log
This makes sure the apache2 error logs go to the containers' STDERR. If I could somehow make all those logging entries have a string like 'ERROR' prepended, I would at least have a semi-workable solution.
But really, having STDERR entries automatically get Severity 'Error' is ideal.
I have a python script called script.py. When I run this script, it creates a logs folder on the Desktop and downloads all the necessary logs from a website and writes them as .log files in this logs folder. I want Fluentd to run this script every 5 minutes and do nothing more. The next source I have on the config file does the real job of sending this log data to another place. If I already have the logs folder on the Desktop, this log files are uploaded correctly to the next destination. But the script never runs. If I delete my logs folder locally, this is the output fluentd gives:
2020-07-27 10:20:42 +0200 [trace]: #0 plugin/buffer.rb:350:enqueue_all: enqueueing all chunks in buffer instance=47448563172440
2020-07-27 10:21:09 +0200 [trace]: #0 plugin/buffer.rb:350:enqueue_all: enqueueing all chunks in buffer instance=47448563172440
2020-07-27 10:21:36 +0200 [debug]: #0 plugin_helper/child_process.rb:255:child_process_execute_once: Executing command title=:exec_input spawn=[{}, "python /home/zohair/Desktop/script.py"] mode=[:read] stderr=:discard
This never gives a logs folder on my Desktop which the script normally does output if run locally like python script.py
If I already have the logs folder, I can see the logs on the stdout normally. Here is my config file:
<source>
#type exec
command python /home/someuser/Desktop/script.py
run_interval 5m
<parse>
#type none
keys none
</parse>
<extract>
tag_key none
</extract>
</source>
<source>
#type tail
read_from_head true
path /home/someuser/Desktop/logs/*
tag sensor_1.log-raw-data
refresh_interval 5m
<parse>
#type none
</parse>
</source>
<match sensor_1.log-raw-data>
#type stdout
</match>
I just need fluentd to run the script and do nothing else, and let the other source take this data and send it to somewhere else. Any solutions?
Problem was solved by creating another #type exec for pip install -r requirements.txt which fulfilled the missing module error which was not being shown on the fluentd error log (Was running fluentd as superuser).
I have a very simple python program I am running in supervisord.
The supervisord.conf is completely default besides the program section:
[program:logwatcher]
command=/path/to/python -u "/path/to/logwatcher.py"
The python code:
import sys
print("print\n")
print("file=sys.stdout\n", file=sys.stdout)
print("file=sys.stderr\n", file=sys.stderr)
sys.stdout.write("sys.stdout.write\n")
sys.stderr.write("sys.stderr.write\n")
Produces this output:
supervisor> tail logwatcher
print
file=sys.stdout
sys.stdout.write
supervisor> tail logwatcher stdout
file=sys.stderr
sys.stderr.write
supervisor> tail logwatcher stderr
file=sys.stderr
sys.stderr.write
why is tail stdout only showing stderr messages, and not stdout messages?
why is tail stdout showing stderr at all?
if tail is supposed to mimic tail stdout why don't they match?
tested on supervisor 3.3.5 and supervisor 4.0.1
I've a daemon process periodically output the info to log file, how can i get these info output to console stdout or stderr?
Thank you in advance.