jschoubben
b8a766f234
novox/hq ADR 0141 and 04-ISSUES/142. A version was being delivered to a machine and nothing started it: the launcher on these machines predates the versions mechanism and runs the fixed binary path, so the delivery was correct and inert. Delivered as a FILE resource, not as part of an archive, and the difference is the whole reason this is safe. A file is written atomically — temp file in the same directory, then rename — so the running launcher keeps the inode it was started from and the next start picks up the new one. An archive writes in place with truncate, which would cut the file a running shell is reading halfway through. The manifest therefore carries a second copy of the script, and a test refuses any difference between it and packaging/nox-mesh-host-launch. Proven by drifting one and watching it fail. Two copies of a script is a bad thing to accept, and the alternative was writing over a running supervisor. Together the two resources complete the loop: the version lands, the running host stands aside because it sees one delivered, and the launcher that starts next is the one that looks in versions/ and picks the newest by arrival.
49 lines
1.6 KiB
Go
49 lines
1.6 KiB
Go
package packaging_test
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import (
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"encoding/json"
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"os"
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"testing"
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)
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// The mesh delivers the launcher, so the manifest carries a copy of it (novox/hq 04-ISSUES/142).
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//
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// **Two copies of one script is a drift waiting to happen**, and the only reason to accept it is that
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// a file resource is written atomically — temp file, then rename — while an archive writes in place
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// with truncate. The running launcher keeps the inode it was started from and the next start picks up
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// the new one; unpacking an archive over it would truncate the file a running shell is reading.
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//
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// So: two copies, and this is the check that they are the same one.
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func TestTheManifestCarriesTheLauncherExactly(t *testing.T) {
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onDisk, err := os.ReadFile("nox-mesh-host-launch")
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if err != nil {
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t.Fatal(err)
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}
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raw, err := os.ReadFile("../module.json")
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if err != nil {
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t.Fatal(err)
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}
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var manifest struct {
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Resources []struct {
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ID string `json:"id"`
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Content string `json:"content"`
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} `json:"resources"`
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}
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if err := json.Unmarshal(raw, &manifest); err != nil {
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t.Fatal(err)
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}
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for _, r := range manifest.Resources {
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if r.ID != "launcher" {
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continue
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}
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if r.Content != string(onDisk) {
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t.Fatal("the launcher the mesh would deliver is not the launcher in this repository. " +
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"Copy packaging/nox-mesh-host-launch into module.json's `launcher` resource — the " +
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"machines run what the manifest says, and this file is what gets reviewed")
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}
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return
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}
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t.Fatal("module.json declares no `launcher` resource, so nothing delivers the launcher and a " +
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"delivered host version is never started")
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}
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