Make the config.toml file more modular by expanding env vars inside it

[trader-payne]

Do you want to request a feature or report a bug?
Feature request

What is the current behavior?
Only some of the parameters can be inserted via env vars

What is the expected behavior?
Similar to b82ac37 but for pretty much anything there is to set inside the toml file.

Example:

[chains.${CHAIN_0}]
shard = "${SHARD_0}"
provider = [ { label = "${CHAIN_0}", url = "${CHAIN_RPC_0}", features = ["${CHAIN_0_FEATURES}"] } ]```

[neysofu]

There's several production-ready tools that perform variable expansion:

• https://www.gnu.org/software/gettext/manual/html_node/envsubst-Invocation.html
• https://github.com/a8m/envsubst (this one is great)
• https://github.com/drone/envsubst

I'd be inclined towards using of of these tools, rather than keep reinventing the wheel inside graph-node. Can you please check if they fit your use case and report back? Thanks 😃

E.g. go install https://github.com/a8m/envsubst/cmd/envsubst@latest && envsubst < graph-node-config.toml.template > graph-node-config.toml.

[neysofu]

We're thinking about adding envsubst to the official graph-node Docker image, which would hopefully fix this problem for most use cases.

[trader-payne]

I've tested it on the host machine and it works wonders! I would love to have this handed off to the graphnode container tho!

[trader-payne]

I managed to integrate this into my Testnet Environment completely hands off, but again, this would be so much better to have in the graph-node container 🙏🏻 I think you can close this issue if you want, or keep it open until/if it's ever integrated 😬 Thanks a lot! You saved a lot of headaches during the MIPs program ser lol

[neysofu]

I'll keep this open, hopefully we can get this sorted in time for 0.29.0 :)