Django application monitoring with datadog

Application performance monitoring

Application performance monitoring (i.e APM) is a way to analyze the each transaction of an application and find the pitfalls of it.

APM allow us to find

• Whether the app is behaving as expected or not?
• What parts of the application is using more resources like Memory, CPU, etc.?
• What queries are taking more time in database?
• How frequently an url is being requested?
• Application availability

With the above information, we can fix the issues and improve the application before it affects the business.

Datadog and it’s features

Datadog is a monitoring service for cloud-scale applications, providing monitoring of servers, databases, tools, and services, through a SaaS-based data analytics platform.

Features

• Allows developer to analyze each request in depth, so that developer can see what part of the application is taking more time.
• It gives the insights on how frequently an API or web page is failing or accessing
• It allows to set the alerts so that developers can be notified if anything goes wrong.
• It allows clear insights on database queries so that dev’s can analyze the issue and fix/improve the DB/Query performance.
• It allows to create the dashboards for different application events and create alerts based on the events. so that people will know before it impact the business.
• It supports different languages and their frameworks also.

Integrating Datadog with django app

Get the API key and install the datadog agent with below command

DD_API_KEY=<API_KEY> DD_AGENT_MAJOR_VERSION=7 bash -c "$(curl -L https://raw.githubusercontent.com/DataDog/datadog-agent/master/cmd/agent/install_script.sh)"

To use the datadog with django we need to install the python package ddtrace with below command.

pip install ddtrace

Now, run the ddtrace-run wrapper with your gunicorn command, keeping all the arguments intact:

ddtrace-run gunicorn [...] myapp.wsgi:application [...]

Update the settings.py file by adding 'ddtrace.contrib.django' to installed apps.

INSTALLED_APPS = [
  # your Django apps...
  'ddtrace.contrib.django',
]

Restart the application and send few requests to the app, we should be able to see the metrics of django application.

Integrating datadog with PostgreSQL

SSH into PostgreSQL server and install the datadog agent with below command. You will need to get the API Key

DD_API_KEY=<API_KEY> DD_AGENT_MAJOR_VERSION=7 bash -c "$(curl -L https://raw.githubusercontent.com/DataDog/datadog-agent/master/cmd/agent/install_script.sh)"

Now, create a postgres user datadog with read-only access.

create user datadog with password '<PASSWORD>';
grant pg_monitor to datadog;
grant SELECT ON pg_stat_database to datadog;

Verify connection using below command

psql -h localhost -U datadog postgres -c \
"select * from pg_stat_database LIMIT(1);" \
&& echo -e "\e[0;32mPostgres connection - OK\e[0m" \
|| echo -e "\e[0;31mCannot connect to Postgres\e[0m"

To configure the Agent to collect PostgreSQL metrics, create a conf.yaml file from the provided template.

sudo cp /etc/datadog-agent/conf.d/postgres.d/conf.yaml.example /etc/datadog-agent/conf.d/postgres.d/conf.yaml

Add the following to config file:

init_config:

instances:
  - host: localhost
    port: 5432
    username: datadog
    password: <PASSWORD>

Note: replace the localhost with actual host name or IP

Restart the agent with below command

sudo service datadog-agent restart

Wait for 5 min, We should be able to see PostgreSQL performance metrics in datadog dashboard.

That’s it folks. You can check their official docs at https://docs.datadoghq.com/

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