Add ansible virtual repositories (#158)

Clients need one Galaxy server to install both internal collections and galaxy.ansible.com ones; ansible has no virtual type.

- merge member collection version lists in member order, the earlier member winning a duplicate version, cached with the shared virtual merge cache
- paginate limit/offset over the merged list, following remote member pages
- serve version detail from the owning member with href and download_url via the virtual; downloads 302 to the member through the member-redirect validation
- fail closed with 502 on a member error or a member versions list shorter than its count
- add docs/ansible/virtual.md and an e2e-docker case driving real ansible-galaxy

requires unkin/artifactapi#157

Reviewed-on: #158
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

e2e-docker/README.md

@@ -37,7 +37,8 @@ already-running stack.
   across two members; npm packument merge over two locals via a stock `node:22`
   client (merged versions, install through the member redirect); gems compact
   index merge over two locals via stock `ruby:3.3` bundler (member order wins,
-  downloads 302 to the owning member).
+  downloads 302 to the owning member); ansible over two locals via stock
+  `ansible-galaxy` (install through the virtual, download 302 to the owner).
 - **Mirrorlist** — an rpm remote with a `mirrorlist` of extra upstream mirrors
   (pool = `base_url` + `mirrorlist`): round-robin distribution across both mirrors
   (constant-body `mockupstreama` / `mockupstreamb`), failover past a dead primary,

e2e-docker/ansible_virtual_test.go

@@ -0,0 +1,64 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+)
+
+// TestVirtualAnsibleInstall publishes a collection to the second of two
+// ansible locals and installs it with stock ansible-galaxy through a virtual
+// over both, the download 302ing to the owning member.
+func TestVirtualAnsibleInstall(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := os.Getenv("ARTIFACTAPI_INTERNAL")
+	if network == "" || internal == "" {
+		t.Skip("COMPOSE_NETWORK/ARTIFACTAPI_INTERNAL not set; run via scripts/docker-e2e.sh")
+	}
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skip("docker not available on the test host")
+	}
+
+	id := time.Now().UnixNano()
+	a, b, virt := fmt.Sprintf("e2e-ansible-a-%d", id), fmt.Sprintf("e2e-ansible-b-%d", id), fmt.Sprintf("e2e-ansible-v-%d", id)
+	for _, name := range []string{a, b} {
+		createRepo(t, fmt.Sprintf(`{"name":%q,"package_type":"ansible","repo_type":"local"}`, name))
+		defer deleteRepo(t, name)
+	}
+	createVirtual(t, fmt.Sprintf(`{"name":%q,"package_type":"ansible","members":[%q,%q]}`, virt, a, b))
+	defer deleteVirtual(t, virt)
+
+	base := strings.TrimRight(internal, "/")
+	script := "set -euo pipefail\n" + ansibleHelloScript + `
+ansible-galaxy collection publish /w/dist/unkin-e2e_hello-1.0.0.tar.gz --server "$BASE/api/v1/local/$B/" --api-key unused
+V="$BASE/api/v1/virtual/$VIRT"
+ansible-galaxy collection install unkin.e2e_hello --server "$V/" -p /w/coll
+DL=$(python3 -c 'import json,sys,urllib.request as u;print(json.load(u.urlopen(sys.argv[1]))["download_url"])' "$V/api/v3/collections/unkin/e2e_hello/versions/1.0.0/")
+echo "REDIRECT $(python3 -c 'import sys,urllib.request as u
+class N(u.HTTPRedirectHandler):
+    def redirect_request(self,*a): return None
+try: u.build_opener(N).open(sys.argv[1])
+except u.HTTPError as e: print(e.code, e.headers["Location"])' "$DL")"
+` + ansibleHelloPlay
+
+	out, err := exec.Command("docker", "run", "--rm", "--network", network,
+		"-e", "BASE="+base, "-e", "B="+b, "-e", "VIRT="+virt,
+		"python:3.12-slim", "bash", "-c", script).CombinedOutput()
+	if err != nil {
+		t.Fatalf("ansible-galaxy client run failed: %v\n%s", err, out)
+	}
+	for _, want := range []string{
+		"unkin.e2e_hello:1.0.0 was installed successfully",
+		"REDIRECT 302 " + base + "/api/v1/local/" + b + "/artifacts/unkin-e2e_hello-1.0.0.tar.gz",
+		"PLAY hello e2e",
+	} {
+		if !strings.Contains(string(out), want) {
+			t.Fatalf("missing %q in client output:\n%s", want, out)
+		}
+	}
+}