6. Harbor Compose Setup

There are a few key points to how Harbor uses Docker that are instrumental for the integration of all the services together.

Dynamic multi-file configuration

Docker offers a multi-file configuration capabilities out of the box. However, it's rarely scaled beyound a few files. The main reason is that it quickly becomes non-trivial to reference multiple files dynamically for various scenarios.

Harbor solves it by using a dynamic file-matcher that revolves around the service handles (ollama, webui, tts, etc.). Those are matched against the docker compose files in the repo to form a set of services and related configurations to run.

It starts with a simple direct match rule, wheer compose file includes the service handle. For example:

# handle
ollama

# compose file
compose.ollama.yml

You can see which files are matching your config by running:

harbor defaults
# webui
# ollama

harbor cmd -h # -h - human readable output
# docker compose
#  - compose.yml
#  - compose.ollama.yml
#  - compose.webui.yml
#  - compose.x.ollama.nvidia.yml
#  - compose.x.ollama.webui.yml

Let's review the rules that made these files to be included.

Multi-service file

File name uses OR for default segment matching:

# Will match whenever either litellm
# langfuse or postgres handles are mentioned
compose.litellm.langfuse.postgres.yml

# Will be included for any of below launches
harbor up litellm
harbor up langfuse
harbor up postgres

It allows to create setups where, for example, multiple backends are all using the same DB instance.

Cross-service file

When there's an .x. in the file name, all mentioned handles are required to be present, effectively making it an AND rule:

# Will only match when both litellm and langfuse
# handles are mentioned
compose.x.litellm.langfuse.yml

# Match
harbor up litellm langfuse

# No match
harbor up litellm
harbor up langfuse
harbor up tts

This allows implementing cases where one services has a direct impact on configuration of another. For example, configuring something in Open WebUI when SearxNG is running.

Environment-specific files

Matched automatically, for example:

# Will be included to any "harbor up" if
# calls if the nvidia container toolkit
# and drivers are installed
compose.service.nvidia.yml

Default services

Default services are picked from the config and are always included. They can be set via the .env file or the CLI:

# Via .env
harbor config list | grep SERVICES_DEFAULT
# SERVICES_DEFAULT="webui ollama"

# CRUD for defaults
harbor defaults ls
harbor defaults add tts
harbor defaults rm webui

# Using "harbor config"
harbor config get services.default
# webui ollama

Apart from these, harbor also always mentions root compose.yml file, which is the base for all the services.

Shared environment

The .env file is used for all the services at once. It's done for the end-user convenience at the expense of potential conflicts. When service's env is overly abstract - Harbor will prefer to use prefixed HARBOR_ variables and add them via environment section in the compose file.

Config Merging

Some services have their configs assembled at runtme from multiple files. It's useful for cases where running a service might have an impact on configuration of another service.

For example: tts and webui. When tts is running, webui should be configured to use it as a TTS backend.

harbor cmd
# -f webui.yml
# -f ollama.yml

# See sections above to learn why these
# files are included
harbor cmd tts -h
# docker compose
#  - compose.yml
#  - compose.ollama.yml
#  - compose.tts.yml
#  - compose.webui.yml
#  - compose.x.ollama.nvidia.yml
#  - compose.x.tts.nvidia.yml
#  - compose.x.webui.ollama.yml
#  - compose.x.webui.tts.yml

webui.yml comes with a default config.json file, that's used by the WebUI. x.webui.tts.yml mounts additional file to the container - config.tts.json, a subset of webui's own configuration.

At runtime, we replace container's entrypoint with a custom one that is aware of all the optionally added volumes. It collect all configuration pieces from them and assemebles them together into a final config.json for the WebUI to consume.

See the config merger util for more details.

Config Interpolation

Config mergers come with additional bit of functionality related to env interpolation.

Variable substitution

{
  "key": "${HARBOR_ENV_VAR}"
}

Would be replaced with the value of HARBOR_ENV_VAR from the .env file.

HARBOR_ENV_VAR="value"

After config merging, becomes:

{
  "key": "value"
}

Variable spread

{
  "items": [
    "item0",
    "${...HARBOR_ENV_VAR}"
  ]
}

Would be replaced with the value of HARBOR_ENV_VAR from the .env file, but as a list of items.

HARBOR_ENV_VAR="item1;item2;item3"

After config merging, becomes:

{
  "items": [
    "item0",
    "item1",
    "item2",
    "item3"
  ]
}