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Running multiple applications on one host

The problem

When running multiple applications on one host some odd behavior may occur. One common problem we've seen is that Applications start reporting under different names and/or environments. Such as an application switching between the staging and production environment after a deploy or restart of an application process or worker.

Background

The AppSignal agent starts using an application config. It uses this configuration to send the data to the AppSignal servers to report it as that app on AppSignal.com.

By default AppSignal is configured to assume one application runs on one host. If you run more than one application on a host, some configuration is required to avoid sharing the AppSignal working directory between multiple applications. This way multiple AppSignal agents can run at the same time with a different application config.

Read more about the AppSignal working directory.

Configuration

To allow AppSignal to be used for multiple applications on one host we need to set the "working directory path" configuration option. Using this configuration option, we need to set a unique working directory path per application for AppSignal to store its (temporary) files. This way the AppSignal agent will not share the working directory between multiple applications.

Ruby

To set the working directory path in the Ruby integration, add the following to your AppSignal configuration file. The working_directory_path value is a path to an existing directory on your host system.

YAML
# Example: config/appsignal.yml
production:
  working_directory_path: "/tmp/project_1/"

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Elixir

To set the working directory path in the Elixir integration, add the following to your AppSignal configuration file. The working_directory_path value is a path to an existing directory on your host system.

Elixir
# Example: config/appsignal.exs
config :appsignal, :config,
  working_directory_path: "/tmp/project_1/"

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Node.js

To set the working directory path in the Node.js integration, add the following to your AppSignal configuration file. The workingDirectoryPath value is a path to an existing directory on your host system.

Node.js
// Example: appsignal.js
const { Appsignal } = require("@appsignal/nodejs");
 
const appsignal = new Appsignal({
  // Other config
  workingDirectoryPath: "/tmp/project_1",
});
 
module.exports = { appsignal };

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Python

For the Python integration, two config options need to be changed. The first is the working_directory_path config option, and the other the opentelemetry_port config option.

To set these config options in the Python integration, add the following to your AppSignal configuration file. The opentelemetry_port value is a number of a port that is available and the working_directory_path value is a path to an existing directory on your host system. These should be unique values per app.

Python
# Example: __appsignal.py
from appsignal import Appsignal
 
appsignal = Appsignal(
  # Other config
  opentelemetry_port: 9001,
  working_directory_path: "/tmp/project_1"
)

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Front-end JavaScript

No working directory can be configured for Front-end JavaScript applications as it does not rely on the AppSignal agent process. If data is reported for the wrong application, please make sure the application is using the correct Push API key

See also