experiments/layered-server-config

experiments/layered-server-config/README.md

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+# Experimenting with service groups
+
+    syndicate-server -c ./boot

experiments/layered-server-config/boot/010-milestone.pr

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+; To "run" a milestone service,
+;  - assert that it is both started and ready
+;  - that's it!
+;
+? <run-service <milestone ?m>> [
+  <service-state <milestone $m> started>
+  <service-state <milestone $m> ready>
+  $log ! <log "-" { service: <milestone $m> state: up }>
+  ?- <log "-" { service: <milestone $m> state: down }>
+]

experiments/layered-server-config/boot/010-service-state-up.pr

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+; To the usual suite of service states we add `up`, meaning "either `ready` or `complete`".
+;
+? <service-state ?x ready> <service-state $x up>
+? <service-state ?x complete> <service-state $x up>

experiments/layered-server-config/boot/020-load-system-layer.pr

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+; Attenuate `$config` by rewriting plain `require-service` assertions to
+; `require-system-service` assertions. Allow all other assertions through.
+;
+let ?sys = <* $config [
+  <rewrite <require-service ?s> <require-system-service $s>>
+  <filter _>
+]>
+
+; Give meaning to `require-system-service`: it is an ordinary `require-service`, plus a
+; declaration that the `system-layer` milestone depends on the service.
+;
+? <require-system-service ?s> [
+  <depends-on <milestone system-layer> <service-state $s up>>
+  <require-service $s>
+]
+
+; Load config in the `system-layer` directory, using the wrapped `config` so that all plain
+; services required are changed to be *system* services.
+;
+<require-service <config-watcher "./system-layer" {
+  config: $sys
+  gatekeeper: $gatekeeper
+  log: $log
+}>>
+
+; In addition, require the `system-layer` milestone explicitly.
+;
+<require-service <milestone system-layer>>

experiments/layered-server-config/boot/030-load-services.pr

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+; Attenuate `$config` by rewriting plain `require-service` assertions to
+; `require-basic-service` assertions. Allow all other assertions through.
+;
+let ?basic = <* $config [
+  <rewrite <require-service ?s> <require-basic-service $s>>
+  <filter _>
+]>
+
+; Give meaning to `require-basic-service`: it is an ordinary `require-service`, plus a
+; declaration that the service depends on the `system-layer` milestone.
+;
+? <require-basic-service ?s> [
+  <depends-on $s <service-state <milestone system-layer> up>>
+  <require-service $s>
+]
+
+; Once we see that the `system-layer` milestone is ready, start processing the `services`
+; directory.
+;
+? <service-state <milestone system-layer> up> [
+  <require-service <config-watcher "./services" {
+    config: $basic
+    gatekeeper: $gatekeeper
+    log: $log
+  }>>
+]

experiments/layered-server-config/services/mock-httpd.pr

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+<require-service <daemon httpd>>
+
+<daemon httpd <one-shot "echo httpd">>
+

experiments/layered-server-config/start.sh

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+#!/bin/sh
+make -C ~/src/syndicate-rs
+~/src/syndicate-rs/target/debug/syndicate-server -c boot/

experiments/layered-server-config/system-layer/mock-eudev.pr

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+<require-service <daemon eudev>>
+<require-service <daemon eudev-initial-scan>>
+
+<daemon eudev <one-shot "echo eudev">>
+
+<depends-on <daemon eudev-initial-scan> <service-state <daemon eudev> up>>
+<daemon eudev-initial-scan <one-shot "echo eudev-initial-scan">>