Compose a module's Go service as a process the host runs (hq issue 213, 1 of 2) #252
@@ -0,0 +1,166 @@
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package catalogue
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import (
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"encoding/json"
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"strings"
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"testing"
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)
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// novox/hq issue 213 (ADR 0188 §1, §3): a module's own Go service is a bundle the host runs as a
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// process, not an image. Each test holds one thing that had to change in the composer for the
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// controller to be declared that way.
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const aServiceDigest = "sha256:dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd"
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// aServiceModule is the controller's shape in miniature: it answers tools of its own, its code is a
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// Go bundle a process runs as an account it declares, its secrets belong to that account, it
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// prepares its state, and its process replaces the container it used to run as.
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func aServiceModule(t *testing.T) Manifest {
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t.Helper()
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raw := `{
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"module": "svc", "version": "1", "tools": ["status"], "prepares": true,
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"own-secrets": {"store": "${dir:state}/store"},
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"secrets-owner": "svc",
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"resources": [
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{"id": "state", "type": "directory", "mode": "0700", "place": "mesh", "owner": "svc"},
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{"id": "service", "type": "process", "name": "svc", "artifact": "code",
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"run": ["./svc", "serve"], "user": "svc", "replaces": ["server"],
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"env": {"SVC_STORE_FILE": "${dir:state}/store", "SVC_STORE_PORT": "${seat:mesh-store:5432}"}},
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{"id": "account", "type": "user", "name": "svc", "shell": "/usr/bin/nologin", "home": "/var/lib/svc"}
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],
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"build": {"artifacts": [{"name": "code", "kind": "bundle", "language": "go", "system": "arch",
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"from": "cmd/svc", "binary": "svc"}]}
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}`
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m, err := ParseManifest([]byte(raw))
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if err != nil {
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t.Fatalf("the service's manifest is refused: %v", err)
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}
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resolved, err := m.Resolve([]Built{{Name: "code", Kind: ArtifactBundle,
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Reference: ArtifactStoreScheme + "svc/code@" + aServiceDigest, Digest: aServiceDigest}})
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if err != nil {
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t.Fatal(err)
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}
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return resolved
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}
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func composeTheService(t *testing.T, with Rendering) []map[string]any {
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t.Helper()
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with.Needed = map[string]map[string]string{"svc": {"store": "sealed-store"}}
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with.ArtifactStore = "anchor.internal:5100"
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out, err := Resolution{Node: "anchor", Modules: []Manifest{aServiceModule(t)}}.Declaration(with)
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if err != nil {
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t.Fatalf("the service does not compose: %v", err)
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}
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return out
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}
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func indexOf(out []map[string]any, id string) int {
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for i, r := range out {
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if r["id"] == id {
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return i
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}
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}
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return -1
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}
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// A module that declares tools has every bundle served by the node's runtime unless it says
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// otherwise — and the controller declares the verbs it answers as tools. Its service bundle is run
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// by its own process; launched a second time by the runtime it would be a second controller
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// pretending to be an MCP server.
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func TestABundleItsOwnProcessRunsIsNotServedByTheRuntime(t *testing.T) {
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m := aServiceModule(t)
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if len(m.Bundles) != 1 {
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t.Fatalf("the service's bundle was not kept: %+v", m.Bundles)
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}
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if loads := m.Bundles[0].Loads; len(loads) != 0 {
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t.Fatalf("the runtime would launch the service's own bundle as tools: %v", loads)
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}
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// And a bundle no resource runs still is served, as a module declaring tools always had it.
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tools := Manifest{Module: "t", Version: "1", Tools: []string{"x"},
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Build: &Build{Artifacts: []Artifact{{Name: "tools", Kind: ArtifactBundle, Language: "go",
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System: "arch", From: "cmd/t"}}}}
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resolved, err := tools.Resolve([]Built{{Name: "tools", Kind: ArtifactBundle,
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Reference: ArtifactStoreScheme + "t/tools@" + aServiceDigest, Digest: aServiceDigest}})
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if err != nil {
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t.Fatal(err)
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}
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if loads := resolved.Bundles[0].Loads; len(loads) != 1 || loads[0] != "t" {
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t.Fatalf("a tools bundle nothing runs is no longer served: %v", loads)
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}
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}
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// The account is created before anything is given to it. Its secrets are mesh-computed and so
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// placed before the module's own resources; given to a user the machine did not have yet, they were
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// refused on the first apply and the process started without them.
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func TestAModulesAccountComesBeforeWhatBelongsToIt(t *testing.T) {
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out := composeTheService(t, Rendering{})
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account, secret := indexOf(out, "svc.account"), indexOf(out, "svc."+NeedID("store"))
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if account < 0 || secret < 0 {
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t.Fatalf("the account or the secret is missing: %v", out)
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}
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if account > secret {
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t.Fatalf("the secret owned by svc is written before svc exists: account at %d, secret at %d",
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account, secret)
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}
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if owner := out[secret]["owner"]; owner != "svc" {
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t.Errorf("the secret belongs to %v, not the account its process runs as", owner)
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}
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}
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// The process is the module's program; its preparation is the same program asked to prepare, as a
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// step before it — with the same account and environment, and handing nothing over.
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func TestAProcessIsPreparedByItsOwnProgram(t *testing.T) {
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out := composeTheService(t, Rendering{})
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step, process := indexOf(out, "svc.service-prepare"), indexOf(out, "svc.service")
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if step < 0 || process < 0 || step > process {
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t.Fatalf("the preparation is not a step before the process (%d, %d): %v", step, process, out)
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}
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s := out[step]
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if s["type"] != "process" || s["run-once"] != true || s["name"] != "svc-prepare" {
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t.Errorf("the preparation is not a run-once process: %v", s)
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}
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if run, _ := json.Marshal(s["run"]); string(run) != `["./svc","prepare"]` {
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t.Errorf("the preparation runs %s", run)
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}
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if s["user"] != "svc" || s["source"] != out[process]["source"] {
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t.Errorf("the preparation does not run the same bundle as the same account: %v", s)
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}
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if env, _ := s["env"].(map[string]any); env["SVC_STORE_FILE"] == nil {
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t.Errorf("the preparation is not given the process's environment: %v", s["env"])
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}
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if _, has := s["replaces"]; has {
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t.Errorf("the preparation would hand over what the process replaces: %v", s)
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}
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if _, has := s["args"]; has {
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t.Errorf("the preparation carries a container's args: %v", s)
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}
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}
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// What the process replaces is named as the host recorded it, `<module>.<id>`; unprefixed, the host
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// matches nothing and removes the container first, as before.
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func TestWhatAProcessReplacesIsNamedAsTheHostRecordedIt(t *testing.T) {
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out := composeTheService(t, Rendering{})
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p := out[indexOf(out, "svc.service")]
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if got, _ := json.Marshal(p["replaces"]); string(got) != `["svc.server"]` {
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t.Fatalf("the process replaces %s", got)
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}
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}
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func TestWhatReplacesMayNameIsRefusedNearItsAuthor(t *testing.T) {
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for what, resource := range map[string]string{
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"a container": `{"id":"c","type":"container","name":"c","image":"x@` + aServiceDigest + `","replaces":["old"]}`,
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"a step": `{"id":"p","type":"process","name":"p","run":["./p"],"run-once":true,"replaces":["old"]}`,
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"something declared": `{"id":"p","type":"process","name":"p","run":["./p"],"replaces":["p"]}`,
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"another module's": `{"id":"p","type":"process","name":"p","run":["./p"],"replaces":["other.old"]}`,
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"not a list": `{"id":"p","type":"process","name":"p","run":["./p"],"replaces":"old"}`,
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} {
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raw := `{"module":"m","version":"1","resources":[` + resource + `]}`
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if _, err := ParseManifest([]byte(raw)); err == nil || !strings.Contains(err.Error(), "replace") {
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t.Errorf("replaces on %s was accepted: %v", what, err)
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}
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}
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ok := `{"module":"m","version":"1","resources":[{"id":"p","type":"process","name":"p","run":["./p"],"replaces":["old"]}]}`
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if _, err := ParseManifest([]byte(ok)); err != nil {
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t.Errorf("a process replacing what its module no longer declares was refused: %v", err)
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}
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}
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@@ -77,6 +77,7 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
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// build compare equal.
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out.Bundles = nil
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if m.Build != nil {
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run := runByAResource(m)
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for _, a := range m.Build.Artifacts {
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if a.Kind != ArtifactBundle {
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continue
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@@ -84,8 +85,13 @@ func (m Manifest) Resolve(built []Built) (Manifest, error) {
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made := by[a.Name]
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// What the runtime loads: what the artifact said, else every entrypoint of a module
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// that declares tools, else nothing (the field's own rule; see Artifact.Loads).
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//
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// **Never, unasked, a bundle one of the module's own resources runs** (novox/hq issue 213).
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// A process the host runs is the module's service, not its tools: the controller declares
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// the verbs it answers as `tools` and serves them itself, and its bundle would otherwise
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// have been launched a second time by the node's runtime, as an MCP child it is not.
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loads := append([]string(nil), a.Loads...)
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if a.Loads == nil && len(m.Tools) > 0 {
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if a.Loads == nil && len(m.Tools) > 0 && !run[a.Name] {
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loads = append([]string(nil), a.Entrypoints...)
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// A bundle compiled to a binary has no entrypoints: the binary is what it is, and what
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// the runtime starts to serve it (novox/hq ADR 0193). So a Go tools bundle is served
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@@ -453,6 +459,18 @@ func BinaryOf(a Artifact) string {
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return a.Name
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}
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// runByAResource is the artifacts one of a module's own resources names — a process that runs it,
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// a step, an archive that unpacks it — by name.
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func runByAResource(m Manifest) map[string]bool {
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named := map[string]bool{}
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for _, r := range m.Resources {
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if a, ok := r["artifact"].(string); ok && a != "" {
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named[a] = true
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}
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}
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return named
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}
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// undeliveredBundles says which of a module's bundles nothing would ever put on a machine (novox/hq
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// 04-ISSUES/216). A bundle reaches a machine three ways: the node's runtime serves it (it says
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// `loads`, or its module declares `tools`), a resource names it (a process, a step, an archive), or
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@@ -463,12 +481,7 @@ func undeliveredBundles(m Manifest) []string {
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if m.Build == nil || m.Module == RuntimeModule {
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return nil
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}
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named := map[string]bool{}
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for _, r := range m.Resources {
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if a, ok := r["artifact"].(string); ok && a != "" {
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named[a] = true
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}
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}
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named := runByAResource(m)
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var problems []string
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for _, a := range m.Build.Artifacts {
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if a.Kind != ArtifactBundle || named[a.Name] || len(a.Loads) > 0 || len(m.Tools) > 0 {
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@@ -693,7 +693,15 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
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// Now, and not before: a module whose resources are computed replaces them wholesale, and
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// merging earlier would throw away the files it still needs.
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resources = append(append([]map[string]any{}, first...), resources...)
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//
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// **Except the module's own accounts, which go before even those** (novox/hq issue 213). What
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// the mesh computes may belong to one: a module whose code runs as an account it declares has
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// its secrets written owned by that account, and a file given to a user the machine does not
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// have yet fails — so on the first apply the secrets were refused, the process started without
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// them, and the second apply healed it, which is the fault the paragraph above describes.
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// An account depends on nothing the mesh computes.
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accounts, rest := accountsFirst(resources)
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resources = append(append(accounts, first...), rest...)
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// No container is given the mesh's names (novox/hq ADR 0148). It used to be: every
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// container got the whole roster as `--add-host` entries at creation, and a name that
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@@ -872,6 +880,12 @@ func (r Resolution) compose(with Rendering, owner map[string]string,
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if renamed := reflectsRenamed(m.Module, resource["reload-on"]); renamed != nil {
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copied["reload-on"] = renamed
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}
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// And what a process replaces (novox/hq issue 213): a resource of this module's that it
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// no longer declares, named as the host recorded it, or the host hands nothing over and
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// removes it first.
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if renamed := reflectsRenamed(m.Module, resource["replaces"]); renamed != nil {
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copied["replaces"] = renamed
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}
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// **What reads one of this module's own secrets is restarted when it changes** (novox/hq
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// issue 203, issue 206). A credential is re-issued by the mesh, and a container that
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// mounted the old file keeps the old one open: the build machine ran for an hour on a
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@@ -2010,12 +2024,18 @@ func preparationTarget(m Manifest) string {
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return ""
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}
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for _, r := range m.Resources {
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if fmt.Sprint(r["type"]) != "container" || !ownArtifact(r, m.Module) {
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// A container, or a process the host runs from a bundle the module built (novox/hq issue
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// 213): the same program in the same context, hosted as a unit rather than a container.
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kind := fmt.Sprint(r["type"])
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if (kind != "container" && kind != "process") || !ownArtifact(r, m.Module) {
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continue
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}
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if once, _ := r["run-once"].(bool); once {
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continue
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}
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if r["schedule"] != nil {
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continue
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}
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return fmt.Sprint(r["id"])
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}
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return ""
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@@ -2029,7 +2049,10 @@ func ownArtifact(resource map[string]any, module string) bool {
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return true
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}
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image, _ := resource["image"].(string)
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return strings.HasPrefix(image, ArtifactStoreScheme+module+"/")
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// A process or an archive carries what was built as its source (novox/hq issue 213).
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source, _ := resource["source"].(string)
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return strings.HasPrefix(image, ArtifactStoreScheme+module+"/") ||
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strings.HasPrefix(source, ArtifactStoreScheme+module+"/")
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}
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// prepared is the module's own resource as the step that prepares its state: the same image, the same
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@@ -2051,7 +2074,19 @@ func prepared(from map[string]any) map[string]any {
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step["id"] = fmt.Sprint(from["id"]) + "-prepare"
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step["name"] = fmt.Sprint(from["name"]) + "-prepare"
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step["run-once"] = true
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if fmt.Sprint(from["type"]) == "process" {
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// A process says its whole command: the program, then its arguments. The step is the same
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// program asked to prepare (novox/hq issue 213). It replaces nothing — what the process
|
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// replaces is handed over to the process, never to the step that runs before it — and a
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// step is not restarted, it runs again when what it reads changed, which `restart-on` says.
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run := stringsIn(from["run"])
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if len(run) > 0 {
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step["run"] = []any{run[0], PreparationArgument}
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}
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delete(step, "replaces")
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} else {
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step["args"] = []any{PreparationArgument}
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}
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delete(step, "ports")
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delete(step, "ip")
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delete(step, "schedule")
|
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@@ -2196,3 +2231,16 @@ func withRestartOn(have any, add []string) []any {
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}
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return out
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}
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// accountsFirst splits a module's resources into its accounts and everything else, each in the order
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// written.
|
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func accountsFirst(resources []map[string]any) (accounts, rest []map[string]any) {
|
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for _, r := range resources {
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if fmt.Sprint(r["type"]) == "user" {
|
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accounts = append(accounts, r)
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continue
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}
|
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rest = append(rest, r)
|
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}
|
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return accounts, rest
|
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}
|
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|
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@@ -1515,6 +1515,53 @@ func ParseManifest(raw []byte) (Manifest, error) {
|
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"program that reads what the mesh delivered and reconciles",
|
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m.Module, r["id"]))
|
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}
|
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// **What a process replaces is something the module no longer declares** (novox/hq issue 213).
|
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// The host keeps it running until the process is, then removes it: so it is named by the id the
|
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// module used to give it, it is never a resource the module still declares — that would be
|
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// applied and removed by one declaration — and only a process that stays up has anything to
|
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// hand over to. Said here, near the author, as the host would refuse it far away.
|
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ids := map[string]bool{}
|
||||
for _, r := range m.Resources {
|
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ids[fmt.Sprint(r["id"])] = true
|
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}
|
||||
for _, r := range m.Resources {
|
||||
raw, present := r["replaces"]
|
||||
if !present {
|
||||
continue
|
||||
}
|
||||
if fmt.Sprint(r["type"]) != "process" {
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v says what it replaces, and only a process does", m.Module, r["id"]))
|
||||
continue
|
||||
}
|
||||
if once, _ := r["run-once"].(bool); once || r["schedule"] != nil {
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v replaces something and runs once or on a schedule — only a process that stays "+
|
||||
"up is there a moment later to hand over to", m.Module, r["id"]))
|
||||
}
|
||||
list, ok := raw.([]any)
|
||||
if !ok {
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v replaces %v; replaces is a list of the ids this module no longer declares",
|
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m.Module, r["id"], raw))
|
||||
continue
|
||||
}
|
||||
for _, item := range list {
|
||||
id, ok := item.(string)
|
||||
switch {
|
||||
case !ok || strings.TrimSpace(id) == "":
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v replaces %v, which is not an id", m.Module, r["id"], item))
|
||||
case strings.Contains(id, "."):
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v replaces %q; a process replaces only a resource of its own module, named "+
|
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"by its own id", m.Module, r["id"], id))
|
||||
case ids[id]:
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s: %v replaces %q, which this module still declares", m.Module, r["id"], id))
|
||||
}
|
||||
}
|
||||
}
|
||||
// **A module that prepares its state must have code the mesh can run** (novox/hq ADR 0135). The
|
||||
// preparation is the module's own program in its preparation mode, so it is derived from the
|
||||
// resource that runs that program — and a module declaring none has asked for something the mesh
|
||||
@@ -1522,7 +1569,7 @@ func ParseManifest(raw []byte) (Manifest, error) {
|
||||
// quietly prepares nothing.
|
||||
if m.Prepares && preparationTarget(m) == "" {
|
||||
problems = append(problems, fmt.Sprintf(
|
||||
"%s says it prepares its state, and declares no container running an artifact it built — "+
|
||||
"%s says it prepares its state, and declares no container or process running an artifact it built — "+
|
||||
"the preparation is this module's own program, so there has to be one for the mesh to "+
|
||||
"run it in", m.Module))
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user