Fix #28: Add validation for web-tail.config.toml content

[mishankov]

Summary

• Implemented comprehensive validation for web-tail.config.toml configuration file
• Validation runs during config parsing and catches common errors early
• Added extensive test coverage with 21 test cases

Changes

Validation Rules

• Required fields: Validates that mandatory fields are present for sources and servers
• Source types: Ensures type is one of: local:file, local:docker, local:openclaw, ssh:file, ssh:docker, ssh:openclaw
• Type-specific validation:
  • *:file sources require path
  • *:docker sources require containerId
• SSH sources require:
  • host and port (1-65535)
  • username
  • Either password or privateKeyPath
• Server references: Validates that serverName references an existing server
• Uniqueness: Source and server names must be unique
• Port ranges: All ports must be between 1 and 65535

Implementation

• Added Validate() method to Config struct
• Called from parseConfig() after config is fully resolved
• Returns descriptive error messages with field paths (e.g., sources[0].name)

Testing

• Created config_test.go with 21 test cases
• Tests cover both valid configurations and all error scenarios
• All tests pass successfully

Test plan

• Unit tests pass (go test ./...)
• Validation correctly rejects invalid configs
• Validation accepts valid configs
• Error messages are clear and actionable

Closes #28

🤖 Generated with Claude Code

[mishankov]

@coderabbitai review

[jkrehm]

This PR broke the app for me because I only use local:file and it's requiring port, username, and password/private key for my local server. I can put dummy info in for those properties, but it doesn't seem like that should be necessary.

[mishankov]

@jkrehm can you provide a bit more info about how you use web-tail (docker or executable, what platform) and how your config file looks
Just tested on code from main and macos executable from latest release with default config from repo and validation was happy

[jkrehm]

I use it in a Docker container where I mount the logs that I want to view into the container. Then I point at localhost.

An abbreviated version of my web-tail.config.toml file (only included one source):

[[servers]]
name = "local"
host = "localhost"

[[sources]]
name = "metube_cleanup"
type = "local:file"
serverName = "local"
path = "/logs/jonathan/metube_cleanup.log"

and my docker-compose.yml

services:
  web-tail:
    image: ghcr.io/mishankov/web-tail
    container_name: web-tail
    restart: unless-stopped
    volumes:
      - /home/jonathan/.log:/logs/jonathan:ro

After the validation change I had to update the servers block to:

[[servers]]
name = "local"
host = "localhost"
port = 1
username = "dummy"
password = "dummy"

It's not a big deal, but if there's a way to make the validation smarter, it would let me reduce the noise in my configuration.

[mishankov]

@jkrehm you do not need to use servers for local:* configurations. It useful only for ssh:* configurations, so you can share ssh configurations across sources.
You can drop servers block and serverName key in source completely

[jkrehm]

Oh sweet, that's much simpler. Thanks for the info, and thanks for a useful tool.