Issues

APScheduler

If you check the log files e.g. ~/repo/uwsgi/log/www.hatherleigh.info-scheduler-logger.log and see the scheduler looping, always Adding job tentatively, then there is probably an import error with your jobs e.g schedule_this_function_does_not_exist does not exist in crm.tasks:

scheduler.add_job(
    "crm.tasks:schedule_this_function_does_not_exist",

Flowable

Data Types

Our workflow has a total variable with a value of 1481.47.

Calling the form-data REST API (e.g. /service/form/form-data?taskId=93) throws the following exception:

{
  "exception": "java.lang.Double cannot be cast to java.lang.String",
  "message": "Internal server error"
}

I am not casting the value to a string, so I think Activiti is storing the data internally as a Double.

Note

I have no idea why Activiti cannot cast a Double to a String

Solution

I am using the double data type in the workflow, and it is accepted without any problem. Comparisons are working as long as both data types are a double e.g:

<activiti:formProperty id="total" name="Invoice Value" type="double" required="true"></activiti:formProperty>
<activiti:formProperty id="seniorLevelValue" type="double" required="true"></activiti:formProperty>

<conditionExpression xsi:type="tFormalExpression"><![CDATA[${total <= seniorLevelValue}]]></conditionExpression>

Issue #2

I am now getting:

"java.lang.Integer cannot be cast to java.lang.String"

Is this because my invoice number is a whole number, but is mapped to a string?

Gateway

If your exclusive gateway is not behaving, check the following:

1. Check you are using a gateway.

This example task does not use a gateway, so (I don’t think) the engine knows which route to take next:

Here is the same example task which has the required exclusive gateway:

2. Check the gateway has a Default flow

In the XML file, the default gateway will look like this:

default="sid-54E01C76-51EC-4460-867B-017E84910394"

Tip

If the default flow is empty, then I don’t think the gateway works properly.

Group

I was trying to set a group in the workflow:

activiti:candidateGroups="${hrGroupPk}"

And kept getting the Expression did not resolve to a string or collection of strings exception thrown:

ERROR org.activiti.engine.impl.interceptor.CommandContext
- Error while closing command context
org.activiti.engine.ActivitiIllegalArgumentException:
Expression did not resolve to a string or collection of strings

To solve the issue, the group ID must be converted to a string:

# replace this
# result = self.group
# with:
result = str(self.group.pk)

Here is the diff: https://gitlab.com/kb/workflow/commit/fe4816adaf2d1e5194666356b01c538ee6def6cb

Lock

In /var/log/tomcat9/catalina.0000-00-00.log when restarting Tomcat:

liquibase.exception.LockException:
Could not acquire change log lock.  Currently locked by ...

From Flowable forum - Liquibase changeLogLock…

To resolve the issue, check the following tables in the Flowable database:

act_app_databasechangeloglock
act_cmmn_databasechangeloglock
act_co_databasechangeloglock
act_dmn_databasechangeloglock
act_fo_databasechangeloglock
flw_ev_databasechangeloglock

If you find a locked record e.g:

select * from flw_ev_databasechangeloglock;

 id | locked |       lockgranted       |       lockedby
----+--------+-------------------------+-----------------------
  1 | t      | 2020-08-16 21:58:45.296 | UKAZU1S213 (10.3.3.4)

Warning

From the link above, Clear the locks only if there is no upgrade running. The question is why Flowable crashed!?

Then you can clear the lock:

UPDATE flw_ev_databasechangeloglock SET LOCKED=FALSE, LOCKGRANTED=null, LOCKEDBY=null where ID=1;

Alfresco

Warning ref CPU usage above 90%:

sudo /opt/alfresco-community/libreoffice/scripts/libreoffice_ctl.sh stop
sudo /opt/alfresco-community/libreoffice/scripts/libreoffice_ctl.sh start

From soffice.bin using 100% of CPU

APM

APM didn’t upgrade until I ran the Salt state.

It is also worth checking the release notes.

Celery

AMQP

Note

We use RabbitMQ (AMQP) when we deploy to Windows servers.

If you find Celery wants to use AMQP (amqp/transport.py, Connection refused), then check you created celery.py in your project (or example_appname) folder, and that your __init__.py contains from .celery import app as celery_app. For more information, see Celery (using Redis) and Celery on Windows

No such transport

Running a Django management command on Windows:

File "C:\inetpub\wwwroot\my-site\venv\lib\site-packages\kombu\transport\__init__.py", line 90, in resolve_transport
  raise KeyError('No such transport: {0}'.format(transport))
KeyError: 'No such transport: '

The set_env_test.bat command had the Celery URL in double quotes:

SET CELERY_BROKER_URL="amqp://guest:guest@localhost:5672//"

To fix the issue, I removed the double quotes:

SET CELERY_BROKER_URL=amqp://guest:guest@localhost:5672//

Not Running Tasks

If you find Celery is not running tasks, try the following:

Open Task Manager on Windows and check you have a single instance of celery.exe running. I don’t know why (or even if) multiple instances cause a problem, but a single instance has got us processing tasks again.

If your task is in an app, check you are Using the @shared_task decorator

Stalled

If your application stops / stall on a delay, then redis might not be running:

transaction.on_commit(
    lambda: update_contact_index.delay(self.object.pk)
)

I have no idea how long the timeout is… but it never returned for me!

Windows Service

We have a Windows Service for Waitress and Dramatiq. If they are failing, here are some things to try:

I solved the problem (several times) by copying python37.dll from:

\kb\Python37\

to:

C:\Windows\System32\

To see an error message, try running:

\kb\Python37\Lib\site-packages\win32\pythonservice.exe "KB-Software-Waitress"

Note

This is the code which is run by HandleCommandLine in win32serviceutil.py. I used this to find the "pywintypes35.dll" is missing from your computer message which I fixed by running the next step in these notes.

Try installing pywin32-228.win-amd64-py3.7.exe as a global package using the installer. The installer runs a script called pywin32_postinstall.py which copies DLL files to the correct locations.

Note

Running pip install pypiwin32==219 doesn’t seem to run the pywin32_postinstall.py script, so the service cannot find the DLL files that it needs! Try running it manually using the globally installed python.

To debug the service start-up, add ipdb to the code and then run:

python celery_service_worker.py debug

cron

If a cron script in /etc/cron.d has a . in the file name, then it will not run! (configs with dots in file name not working in /etc/cron.d)

devpi

Certificate

Firewall

If you get 404 errors when attempting to create a certificate using HTTP validation and LetsEncrypt, then check your Firewall. It might not allow incoming connections to port 80 from the LetsEncrypt servers.

To workaround the issue, use LetsEncrypt - DNS to generate the certificate.

python 2

I was getting SSL certificate verify failed errors when using devpi (which uses httpie and requests). To solve the issue, use devpi with a python 3 virtual environment (not python 2).

Could not find a version that satisfies the requirement

I was trying to install Django 3.0.5 and kept getting this error:

Could not find a version that satisfies the requirement django==3.0.5
(from -r requirements/base.txt (line 10))
(from versions: 1.1.3, 1.1.4, 1.2, 1.2.1, 1.2.2, 1.2.3, 1.2.4, 1.2.5, 1.2.6,
...
2.2.3, 2.2.4, 2.2.5, 2.2.6, 2.2.7, 2.2.8, 2.2.9, 2.2.10, 2.2.11, 2.2.12)

Version 3.0.5 was not listed in the versions. I updated devpi thinking there was a problem with our PyPI server, but it didn’t help.

We were running Python 3.5.2 on our CI server. The Django 3.0 release notes says:

Django 3.0 supports Python 3.6, 3.7, and 3.8. We highly recommend and only officially support the latest release of each series. The Django 2.2.x series is the last to support Python 3.5.

To solve the issue, I upgrade the Docker container to use Ubuntu 18.04 (Upgrade container to Ubuntu 18.04).

Index

If you have a local PyPI server, and you do not want to use it, then comment out index-url in:

~/.pip/pip.conf

Killed

My devpi-server --import was not completing and finishing with a Killed message. To solve this issue, increase the available memory on the server. I increased from 1GB to 2GB and the import completed successfully.

Django

Testing File Field

django.core.exceptions.SuspiciousFileOperation:

The joined path (/2020/06/None-example.dat) is located outside of the base
path component (/home/patrick/dev/app/record/media-private)

To solve this issue, load the test file from the MEDIA_ROOT folder e.g:

from django.conf import settings
from pathlib import Path

file_name = Path(
    settings.BASE_DIR, settings.MEDIA_ROOT, "data", "1-2-3.doc"
)
record = Record.objects.create_record(
    "testing", user, file_name=file_name
)

Django Compressor

I had an issue where relative images in css files were not being found e.g:

url(../img/logo-fill.png)

Django Compressor is supposed to convert relative URLs to absolute e.g:

url('https://hatherleigh-info-test.s3.amazonaws.com/dash/img/logo-fill.png?ae4f8b52c99c')

The compress management command creates a manifest file listing the files it creates. On the web server this can be found in:

./web_static/CACHE/manifest.json

On Amazon S3 it is in the CACHE folder.

You can look at the manifest files to find the name of the generated CSS file and look in this file to see if the relative URLs are converted to absolute.

You can use the browser developer tools to see which CSS file is being used.

To solve the issue, I checked the generated CSS file and the links were not relative. I then ran compress and checked the generated CSS file again and the links were absolute. I re-started the Django project on the server and all was OK.

Tip

I also uninstalled django-storages-redux and reinstalled the old version: (git+https://github.com/pkimber/django-storages-py3.git@py3#egg=storages)

… but I don’t think that made a difference?!

Dramatiq

gevent

Compile fails and I can’t find the required dependencies:

x86_64-linux-gnu-gcc: error: src/gevent/libev/corecext.c: No such file or directory
x86_64-linux-gnu-gcc: fatal error: no input files
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

To fix this issue, upgrade pip so it can install wheels.

pika

Error:

ModuleNotFoundError: No module named 'pika'

Make sure django_dramatiq is first in your list of THIRD_PARTY_APPS.

If this doesn’t help, then make sure you have configured your settings files correctly for Dramatiq (don’t forget dev_test.py).

For details, see Configure.

Dropbox

When testing the scripts:

No protocol specified
!! (Qt:Fatal) QXcbConnection: Could not connect to display :0

To stop this error, use a headless connection i.e. ssh into the computer or use a separate console. This will still be an issue if you have a GUI and you sudo to a user who is not running a GUI.

Backup

If the backup server runs out of space:

1. Lots of directories in /tmp called .dropbox-dist* (10Gb)

2. Backup folder for the site had lots of .sql files from presumably failed backup (3Gb)

3. Check the /home/web/tmp folder. Malcolm deleted this, which freed 1.8G of space!

4. Check the /home/web/temp/ folder and track down large files:

   du -sh *
   

5. You could also try (it didn’t free any space for me):

   rm -r /home/web/repo/files/dropbox/<site name>/Dropbox/.dropbox.cache/*
   

Duplicity

gio

If you get this error:

No module named gio

Then:

apt-get install python-gobject-2

Symbolic Links

Duplicity does NOT backup symbolic links… or the contents of symbolic links.

ElasticSearch

For version 6.x issues, see:

1. Update to version 6

2. APM

Connection marked as dead

Errors from the ElasticSearch client saying:

%s marked as dead for %s seconds

The code can be seen here: https://github.com/rhec/pyelasticsearch/blob/master/pyelasticsearch/client.py#L241

My thought is that the pyelasticsearch client is timing out when the cron task re-indexes the data (there are lots of records, so I would expect this to take some time). The connections are pooled, and time-out, so the connection is marked as dead.

To see if this is the problem (or not), I have added BATCH_SIZE and TIMEOUT to the settings:

HAYSTACK_CONNECTIONS = {
    'default': {
        'BATCH_SIZE': 100,
        'ENGINE': 'haystack.backends.elasticsearch_backend.ElasticsearchSearchEngine',
        'INDEX_NAME': '{}'.format(SITE_NAME),
        'TIMEOUT': 60 * 5,
        'URL': 'http://127.0.0.1:9200/',
    },
}

For documentation on these settings: http://django-haystack.readthedocs.org/en/v2.1.0/settings.html

git

git clone fails with “fatal: Out of memory, malloc failed” error

To install the Salt master on a Linux server with less resources, I created a swap file:

df -v
swapon --show
free
fallocate -l 1G /swapfile
ls -lh /swapfile
sudo chmod 600 /swapfile
ls -lh /swapfile
mkswap /swapfile
swapon /swapfile
swapon --show
free

Tip

Instructions from How To Add Swap Space on Ubuntu 16.04

GitLab

If you find Continuous Integration (CI) is running tests from other apps, then check the project setup.cfg file to make sure src is included in the norecursedirs section. For details, see Continuous Integration.

JavaScript

node-sass will not install

This seems to be a very common error:

Error: EACCES: permission denied, mkdir '/usr/lib/node_modules/node-sass/.node-gyp'

The solution seems to be as follows:

npm -g --unsafe-perm install node-sass

LetsEncrypt

404

If you get 404 not found, then check you sudo service nginx reload.

git

If you get an error similar to this from salt state.apply:

ID: letsencrypt-git
Function: git.latest
Name: https://github.com/letsencrypt/letsencrypt
Result: False
Comment: Repository would be updated from 2434b4a to f0ebd13, but there are
uncommitted changes.

Log onto the affected server:

sudo -i
cd /opt/letsencrypt
git status
# checkout the file which is listed (in my case "letsencrypt-auto)
git checkout letsencrypt-auto
git status # should show nothing

init-letsencrypt - memory

virtual memory exhausted: Cannot allocate memory

Certbot has problem setting up the virtual environment.
Based on your pip output, the problem can likely be fixed by
increasing the available memory.

We solved the issue by creating a temporary swap file and then retrying the init-letsencrypt command:

sudo fallocate -l 1G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

Check the swap status with:

sudo swapon -s

Note

I can’t solve the issue, so referring to a colleague… For more information, see https://github.com/certbot/certbot/issues/1081 https://certbot.eff.org/docs/install.html#problems-with-python-virtual-environment

init-letsencrypt - datetime

ImportError: No module named datetime

To solve the issue:

rm -r /home/patrick/.local/

init-letsencrypt - _remove_dead_weakref

I got this error after upgrading to Ubuntu 18.04:

Error: couldn't get currently installed version for /opt/eff.org/certbot/venv/bin/letsencrypt:
...
ImportError: cannot import name _remove_dead_weakref

To solve the issue:

rm -rf /opt/eff.org/certbot/venv/
# run your ``letsencrypt`` command
# /opt/letsencrypt/letsencrypt-auto renew --no-self-upgrade
service nginx restart

SSL Stapling Ignored

Malcolm says that stapling needs a newer version of nginx.

Mail

SparkPost - Blacklisted

Using http://www.mail-tester.com/ we found our domain was blacklisted. The mail app has a facility for sending a test email: Navigate to /mail/create/.

We emailed SparkPost, and they sent the following advice:

Thank you for reporting the blacklist issue!

If you look at the raw reason provided:

522 email sent from spmailtechn.com found on industry URI blacklists
on 2017/05/10 18:11:12 BST, please contact your mail sending service or use
an alternate email service to send your email.
Guide for bulk senders www.bt.com/bulksender

… it is the domain spmailtechn.com that has been blacklisted and not the IP. Your messages are containing spmailtechn.com in the headers because you haven’t set-up a custom bounce domain yet. In order to do so, you can find more information through following link: https://support.sparkpost.com/customer/portal/articles/2371794

Adding a custom bounce domain to your account will also remove spmailtechn.com from your headers and help fully brand all of your emails and also protect you from other senders on SparkPost.

We did the following:

Added a DMARC record to our Digital Ocean account:

TXT / _dmarc.kbsoftware.co.uk / returns v=DMARC1; p=none"

Added a CNAME record to our Digital Ocean account:

mail.kbsoftware.co.uk / is an alias of sparkpostmail.com

Added mail.kbsoftware.co.uk as a Bounce Domain in Sparkpost:

Microsoft Azure

Open ID Connect - Need admin approval

If you get prompted with Need admin approval:

Then be sure to set API permissions…

Microsoft SQL Server

When using the django-mssql-backend requirement and an ENGINE of sql_server.pyodbc in a Django project, you may see these errors:

ModuleNotFoundError: No module named 'sql_server'
'sql_server.pyodbc' isn't an available database backend

I think you can safely ignore this as it still seems to work fine…!?

nginx

502 Bad Gateway

This is a general error. Find the cause by looking in the following files:

sudo -i -u web
# check the files in:
tail -f ~/repo/uwsgi/log/hatherleigh_info.log

sudo -i
tail -f /var/log/nginx/error.log
# check the log files in:
tail -f /var/log/supervisor/

bind() to 0.0.0.0:80 failed

nginx won’t start and /var/log/nginx/error.log shows:

[emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use)
[emerg] 15405#0: bind() to 0.0.0.0:443 failed (98: Address already in use)

When I stopped the nginx service, I could still see the ports being used:

lsof -i :80
lsof -i :443

From bind() to 0.0.0.0:80 failed, killing the users of the port, sorted the issue:

sudo fuser -k 80/tcp
sudo fuser -k 443/tcp

Note

I am not over happy about this solution. But… I guess the processes were started somehow and had not been stopped?

failed (13: Permission denied) using sendfile

sendfile wasn’t working, and the following message appeared in /var/log/nginx/error.log:

2017/05/18 17:34:30 [error] 1835#1835: *315 open()
"/home/web/repo/files/www.hatherleigh.info/document.docx"
failed (13: Permission denied),
client: 80.234.181.37, server: www.hatherleigh.info,
request: "GET /dash/document/issue/version/3/download/ HTTP/1.1",
upstream: "uwsgi://127.0.0.1:3040", host: "www.hatherleigh.info"

The www-data user didn’t have permission to read the file. The permissions were -rw-------.

To solve the problem, add the following to your settings/production.py file:

FILE_UPLOAD_PERMISSIONS = 0o644

Django will then create files with -rw-r--r-- permissions and all will be well.

For more information, see Django Media.

no python application found, check your startup logs for errors

This issue was missing environment variables e.g. NORECAPTCHA_SITE_KEY. I was running tail on the log file for the web application e.g. ~/repo/uwsgi/log/www.hatherleigh.info.log, and I think the error was further up the page (so use vim next time to check).

I found the error by trying to run a management command e.g. www.hatherleigh.info.sh help and it showed the error. Added the missing environment variables to the vassal and all was fine.

PDFObject

https://pdfobject.com/

From Failed to load PDF document, to fix it, I changed:

response['Content-Disposition'] = "attachment; filename={}".format(

to:

response['Content-Disposition'] = "inline; filename={}".format(

PostgreSQL

Resource

apt install pgtop
# this example database is using PGBouncer
pg_top -h localhost -p 6432 -d www_kbsoftware_couk -U www_kbsoftware_couk

Ubuntu 14.04 LTS

Warning

Check you have a backup of all databases on your development machine.

If you have upgraded from a previous version of Ubuntu running Postgres 9.1, you might need to completely remove the old version:

sudo apt-get purge postgresql-9.1

record app

If the conversion isn’t working, then it might be because LibreOffice is running on your Desktop.

Shut it down and the conversion should succeed. The error message will probably be: Cannot find converted file.

python

The system cannot move the file to a different disk drive

Trying to move a file to a Windows UNC path… using shutil.copy or shutil.move or replace ( from pathlib.Path):

[WinError 2] The system cannot find the file specified: '\\\\KBAZ00001\\Watch\\honeydown.png'

The only solution I can find is from Python 3’s pathlib Module: Taming the File System e.g:

import pathlib

source = pathlib.Path(from_file_path)
destination = pathlib.Path(to_file_path)

with destination.open(mode="xb") as fid:
    fid.write(source.read_bytes())

virtualenv using python3 stuck on setuptools, pip, wheel

From setting up environment in virtaulenv using python3 stuck on setuptools, pip, wheel

1. The first solution, was to create the virtualenv using Ubuntu installed packages i.e:

python3 -m venv venv-fabric

2. The second solution (for a python 2 virtual environment is to update the system packages:

sudo -i
pip install --upgrade virtualenv
pip install --upgrade pip

# Ctrl D (no longer root)
virtualenv -v --python=python2.7 venv-fabric

3. The third solution is to use the --no-cache-dir parameter e.g:

pip install --no-cache-dir -r requirements/local.txt

Remote Desktop

If you are having issues connecting Using Remmina, then try removing the User name and Password. This will help you see if the issue is to do with connection or authentication.

Restic

From 0.8.3 Fatal: unable to create lock in backend: invalid data returned:

Fatal: unable to create lock in backend: load <lock...>: invalid data returned

To solve the issue, I deleted the lock from the command line e.g:

ssh 123@usw-s011.rsync.net rm restic/www.hatherleigh.info/backup/locks/811...

Free Space

If you reduce the retention periods using --keep-last, --keep-hourly, --keep-daily, --keep-weekly, --keep-monthly etc, then the space used will not reduce unless you prune the repository e.g:

/home/web/opt/restic -r sftp:123@usw-s011.rsync.net:restic/www.hatherleigh.info/backup prune
/home/web/opt/restic -r sftp:123@usw-s011.rsync.net:restic/www.hatherleigh.info/files prune

Salt

debug

To run the master in the foreground, stop the service, then:

salt-master -l debug

To run the minion in the foreground, stop the service, then:

salt-minion -l debug

doesn't support architecture 'i386'

When adding the following to /etc/apt/sources.list.d/saltstack.list:

deb http://repo.saltstack.com/apt/ubuntu/18.04/amd64/latest bionic main

You may get an error:

N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'http://repo.saltstack.com/apt/ubuntu/18.04/amd64/latest bionic InRelease' doesn't support architecture 'i386'

To solve this issue, insert [arch=amd64]:

deb [arch=amd64] http://repo.saltstack.com/apt/ubuntu/18.04/amd64/latest bionic main

env

I took a long time trying to find the fix for this issue:

Jinja variable 'env' is undefined

I solved it by renaming the variable. I don’t know… but I think perhaps env is a reserved name in Salt?

Firewall

Note

For Ubuntu only…

On the master and minion, open the Firewall for Salt:

ufw allow salt

Java

Getting a weird error (which I don’t really understand):

Cannot find a question for shared/accepted-oracle-license-v1-1

To solve the issue, I ran the following:

# # this showed the issue
# /bin/echo /usr/bin/debconf shared/accepted-oracle-license-v1-1 seen true  | /usr/bin/debconf-set-selections
error: Cannot find a question for shared/accepted-oracle-license-v1-1

# # to solve the issue
# /bin/echo /usr/bin/debconf shared/accepted-oracle-license-v1-1 select true | /usr/bin/debconf-set-selections
# /bin/echo /usr/bin/debconf shared/accepted-oracle-license-v1-1 seen true  | /usr/bin/debconf-set-selections

Jinja variable is undefined

Trying to add a variable to the context of a Jinja template:

Unable to manage file: Jinja variable 'backup' is undefined

I think the issue was the variable name. I tried backup and apple and they both failed. I renamed backup to enable_backup and it worked!

Minion ID

To set the minion id:

# /etc/salt/minion
id: cloud-a

# re-start the minion and accept the key on the master
service salt-minion restart

Note

Might be worth checking out this article instead of editing the minion id: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/set-hostname.html

pillar - refresh

To refresh the Salt pillar on all of your minions:

salt '*' saltutil.refresh_pillar

For more information, see Pillar

virtualenv.managed

I couldn’t get virtualenv.managed working with python 3, so I ended up following the instructions in Using Salt with Python 3 and Pyvenv

Here is the working Salt state: virtualenv using pyvenv

Selenium

If you have issues with Selenium and Firefox, then try the following:

pip install -U selenium

The following issue with chromedriver (v2.22):

File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/chrome/webdriver.py", lin 82, in quit
  self.service.stop()
File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/chrome/service.py", line 97, in stop
  url_request.urlopen("http://127.0.0.1:%d/shutdown" % self.port)
File "/usr/lib/python2.7/urllib2.py", line 154, in urlopen
  return opener.open(url, data, timeout)
File "/usr/lib/python2.7/urllib2.py", line 429, in open
  response = self._open(req, data)
File "/usr/lib/python2.7/urllib2.py", line 447, in _open
  '_open', req)
File "/usr/lib/python2.7/urllib2.py", line 407, in _call_chain
  result = func(*args)
File "/usr/lib/python2.7/urllib2.py", line 1228, in http_open
  return self.do_open(httplib.HTTPConnection, req)
File "/usr/lib/python2.7/urllib2.py", line 1198, in do_open
  raise URLError(err)
urllib2.URLError: <urlopen error [Errno 111] Connection refused>

Was resolved by updating the version of chromedriver to v2.24.

SOLR

The current version of Haystack has an issue with the simple_backend.py: https://github.com/toastdriven/django-haystack/commit/49564861

To temporarily fix the issue:

cdsitepackages
vim +67 haystack/backends/simple_backend.py

Edit the code so that it matches the fixed version on GitHub i.e:

for field in model._meta.fields:

Ubuntu

Clearing “System Problem Detected” messages

Sometimes historical “System Problem Detected” message re-appear when Ubuntu is started.

For example a problem with the chrome browser may not be reported to Ubuntu because the Chrome is not a supported package.

These message are from files stored in the /var/crash directory.

Investigate old crash messages

Change to the crash reporting directory as follows:

cd /var/crash

View the files in the directory as follows:

ls -al

Files that end with .crash are ascii files containing the crash report detail. You can view them with your favourite editor (e.g. vim, nano or gedit). Some crash reports are readable by root only so you may need to use sudo to be able to view them.

To use vim type:

sudo vim *.crash

To use nano type:

sudo nano *.crash

To use gedit type:

gksu gedit *.crash

You’ll be prompted for your password and on successful entry go to your editor

Delete historical crash messages

To delete historical crash messages type

sudo rm /var/crash/*

Any new crash messages that appear after that should be investigated.

uwsgi

It seems that a new cloud server using python 3 doesn’t install uwsgi correctly into the virtual environment.

Check the supervisor error log for uwsgi:

/var/log/supervisor/uwsgi-stderr

If you get the following:

exec: uwsgi: not found

Then:

sudo -i -u web
cd /home/web/repo/uwsgi
. venv_uwsgi/bin/activate
pip install uwsgi==2.0.1

The version of uwsgi can be found in https://github.com/pkimber/salt/blob/master/uwsgi/requirements3.txt

Windows

Issue with time when dual booting

To correctly synchronise the time in windows when dual booting start regedit and navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation

Right click anywhere in the right pane and choose New | DWORD (32-bit) Value. Name it:

RealTimeIsUniversal

then double click on it and give it a value of 1

see Incorrect Clock Settings in Windows When Dual-Booting with OS X or Linux