opencode/packages/opencode/src/server/routes/instance/httpapi/middleware/error.ts

import { NamedError } from "@opencode-ai/core/util/error"
import * as Log from "@opencode-ai/core/util/log"
import { ConfigError } from "@/config/error"
import { Cause, Effect } from "effect"
import { HttpRouter, HttpServerError, HttpServerRespondable, HttpServerResponse } from "effect/unstable/http"
import fs from "fs/promises"

const log = Log.create({ service: "server" })
const errorLogPath = "/tmp/opencode-http-errors.log"

function writeHttpError(cause: Cause.Cause<unknown>, error: unknown) {
  void fs.appendFile(
    errorLogPath,
    JSON.stringify({
      time: new Date().toISOString(),
      error: error instanceof Error ? error.message : String(error),
      stack: error instanceof Error ? error.stack : undefined,
      cause: Cause.pretty(cause),
    }) + "\n",
  )
}

// Keep typed HttpApi failures on their declared error path; this boundary only replaces defect-only empty 500s.
export const errorLayer = HttpRouter.middleware<{ handles: unknown }>()((effect) =>
  effect.pipe(
    Effect.catchCause((cause) => {
      const defect = cause.reasons.filter(Cause.isDieReason).find((reason) => {
        if (HttpServerResponse.isHttpServerResponse(reason.defect)) return false
        if (HttpServerError.isHttpServerError(reason.defect)) return false
        if (HttpServerRespondable.isRespondable(reason.defect)) return false
        return true
      })
      if (!defect) return Effect.failCause(cause)

      const error = defect.defect
      if (
        error instanceof NamedError &&
        (ConfigError.InvalidError.isInstance(error) || ConfigError.JsonError.isInstance(error))
      ) {
        return Effect.succeed(HttpServerResponse.jsonUnsafe(error.toObject(), { status: 400 }))
      }

      log.error("failed", { error, cause: Cause.pretty(cause) })

      return Effect.succeed(
        HttpServerResponse.jsonUnsafe(
          new NamedError.Unknown({
            message: "Unexpected server error. Check server logs for details.",
          }).toObject(),
          { status: 500 },
        ),
      )
    }),
  ),
).layer