andrew-malikov / eko

Eko

• Eko
  • Overview
    • Storage layers
    • Docker socket format
    • Arrange logs
  • Develop
    • Docker
    • Install deps
    • Environment variables
    • Run with docker compose
    • Bundle and run yourself
  • Example
  • Questions

Eko is an example service to arrange containers' logs. Nothing new and nothing fancy, go ahead.

Overview

The main focus is made on a few things

• arrange logs from a particular docker socket
• get a stream of those

Storage layers

Eko supports multiple storage layers via ENV in format of "<storage-name>::<connection-string>".

For now, there are only two fs and mongo. The fs config is very simple so that the whole right part after :: is treated as path where to store the logs. For mongo the right part is the connection string.

Docker socket format

When eko subscribes to a docker socket it expects it to be like "remote::<address>" or "local::<path>".

Arrange logs

The API to arrange logs from a docker socket support a mandatory filter, the one docker uses under the hood. You can take a deeper look in the official docs.

Develop

Docker

You need to have docker one way or the other, either on local or remotely on a machine with open port to access docker socket.

Install deps

npm i

Environment variables

Copy the example env file and adjust vars you need:

cp .config/.env.example .env

Run with docker compose

docker compose --env-file .env -f build/docker-compose.yml -p ekoserver up --build

Bundle and run yourself

Bundle the server:

npm run bundle

Append the variables to current shell:

export $(cat .env | xargs)

Run the bundled server with node:

node bundle

Example

Outdated since replacing CLI with a server solution

Other thing to consider is to use docker-compose with mongodb docker compose -p mongo -f example/docker-compose.mongo.yaml up You will need to provide -s "mongo::mongodb://superadmin:neverguessit@localhost:27017/eko?authSource=admin" when you call ./binary/eko log arrange and other commands. By default eko is going to use fs storage with logs location under ./logs.

Build eko binary:

npm i && npm run binary

Run that docker compose to have a set of container to arrange logs from:

docker compose -p eko -f example/docker-compose.yaml up --force-recreate --always-recreate-deps --build

and then run eko:

./binary/eko log arrange "name=lorem"

See the logs in the ./logs folder.

Additionally, you can show up the logs via eko. Firstly, you need to get the container id you want to show up via

./binary/eko log list

and finally, bring the logs:

./binary/eko log show <container-id>

Questions

Q: Does this logging service observe container while running or only one time at the startup?

A: It does observe each X amount of seconds. But it's not configurable now.

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Q: Can I run multiple such logging services that listen the same containers with the same storage?

A: Nope, right now it would probably fail. At least with the FS storage, some of the services would fail to write to the same file.

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Q: Does eko arrange logs with the last saved position?

A: Yep, it does.