pkg/config: add config file search order test

Until now there didn't seem to exists a proper that that actually
verifies the containers.conf loading order so fix that. The test got a
bit complicated but I coud not find something better.

Signed-off-by: Paul Holzinger <[email protected]>

Author: Luap99

pkg/config/search_order_test.go

@@ -0,0 +1,135 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	. "github.com/onsi/ginkgo/v2"
+	"github.com/onsi/gomega"
+)
+
+var _ = Describe("search order", func() {
+	It("config file parsing order", func() {
+		// High level idea, we define 12 file lookup paths. Then we simulate parsing
+		// of that file tree for all three cases, uid 0 (root), uid 1000 (reads rootless
+		// specific config files) and uid 500 (also reads rootless config files but not
+		// the uid 1000 specific one)
+		//
+		// To know that each file is getting parsed we use 12 config values and 12 files,
+		// each file in the order is populated with one less config value.
+		// So the first value only exits in the /usr/ file and then the next file writes
+		// one less config value but instead increments the values by one so we can
+		// differentiate what value is in what file.
+
+		configPaths := []string{
+			"/usr/share/containers/containers.conf",
+			"/etc/containers/containers.conf",
+			"/etc/containers/containers.conf.d/1.conf",
+			"/etc/containers/containers.conf.d/2.conf",
+			"/etc/containers/containers.rootless.conf",
+			"/etc/containers/containers.rootless.conf.d/3.conf",
+			"/etc/containers/containers.rootless.conf.d/4.conf",
+			"/etc/containers/containers.rootless.conf.d/1000/5.conf",
+			"/etc/containers/containers.rootless.conf.d/1000/6.conf",
+			"/home/.config/containers/containers.conf",
+			"/home/.config/containers/containers.conf.d/7.conf",
+			"/home/.config/containers/containers.conf.d/8.conf",
+		}
+
+		configFileValues := []string{
+			`apparmor_profile = "apparmor%d"`,
+			`base_hosts_file = "base%d"`,
+			`cgroupns = "cgroupns%d"`,
+			`cgroups = "cgroups%d"`,
+			`host_containers_internal_ip = "host%d"`,
+			`init_path = "init%d"`,
+			`ipcns = "ipcns%d"`,
+			`log_driver = "logdriver%d"`,
+			`log_tag = "logtag%d"`,
+			`netns = "netns%d"`,
+			`pidns = "pidns%d"`,
+			`seccomp_profile = "seccomp%d"`,
+		}
+
+		test := func(config *Config, uid int, testname string) {
+			gomega.Expect(config.Containers.ApparmorProfile).To(gomega.Equal("apparmor1"), testname)
+			gomega.Expect(config.Containers.BaseHostsFile).To(gomega.Equal("base2"), testname)
+			gomega.Expect(config.Containers.CgroupNS).To(gomega.Equal("cgroupns3"), testname)
+			gomega.Expect(config.Containers.Cgroups).To(gomega.Equal("cgroups4"), testname)
+
+			// This is a bit confusing but I did not find a way to make it better readable.
+			// Basically we have three cases here:
+			//  - uid 0 (root): should not read containers.rootless.conf, values must stay at 4
+			//  - uid != 1000: should read containers.rootless.conf but not
+			//                 containers.rootless.conf.d/1000/*.conf, values for the 1000 files must be 7
+			//  - uid == 1000: all files are read so each value should be incremented by 1
+			hostIP := "host5"
+			initPath := "init6"
+			ipcns := "ipcns7"
+			logDriver := "logdriver7"
+			logTag := "logtag7"
+			switch uid {
+			case 0:
+				hostIP = "host4"
+				initPath = "init4"
+				ipcns = "ipcns4"
+				logDriver = "logdriver4"
+				logTag = "logtag4"
+			case 1000:
+				logDriver = "logdriver8"
+				logTag = "logtag9"
+			}
+			gomega.Expect(config.Containers.HostContainersInternalIP).To(gomega.Equal(hostIP), testname)
+			gomega.Expect(config.Containers.InitPath).To(gomega.Equal(initPath), testname)
+			gomega.Expect(config.Containers.IPCNS).To(gomega.Equal(ipcns), testname)
+			gomega.Expect(config.Containers.LogDriver).To(gomega.Equal(logDriver), testname)
+			gomega.Expect(config.Containers.LogTag).To(gomega.Equal(logTag), testname)
+
+			gomega.Expect(config.Containers.NetNS).To(gomega.Equal("netns10"), testname)
+			gomega.Expect(config.Containers.PidNS).To(gomega.Equal("pidns11"), testname)
+			gomega.Expect(config.Containers.SeccompProfile).To(gomega.Equal("seccomp12"), testname)
+		}
+
+		// sanity check
+		gomega.Expect(configFileValues).To(gomega.HaveLen(len(configPaths)))
+
+		tmpdir := GinkgoT().TempDir()
+		for i, path := range configPaths {
+			path := filepath.Join(tmpdir, path)
+			err := os.MkdirAll(filepath.Dir(path), 0o755)
+			gomega.Expect(err).ToNot(gomega.HaveOccurred())
+
+			f, err := os.Create(path)
+			gomega.Expect(err).ToNot(gomega.HaveOccurred())
+			_, err = f.WriteString("[containers]\n")
+			gomega.Expect(err).ToNot(gomega.HaveOccurred())
+			for _, val := range configFileValues[i:] {
+				_, err = fmt.Fprintf(f, val+"\n", i+1)
+				gomega.Expect(err).ToNot(gomega.HaveOccurred())
+			}
+			f.Close()
+		}
+
+		paths := &paths{
+			usr:  filepath.Join(tmpdir, "/usr/share/containers/containers.conf"),
+			etc:  filepath.Join(tmpdir, "/etc/containers/containers.conf"),
+			home: filepath.Join(tmpdir, "/home/.config/containers/containers.conf"),
+			uid:  1000,
+		}
+
+		config, err := newLocked(&Options{}, paths)
+		gomega.Expect(err).ToNot(gomega.HaveOccurred())
+		test(config, 1000, "lookup with uid 1000")
+
+		paths.uid = 500
+		config, err = newLocked(&Options{}, paths)
+		gomega.Expect(err).ToNot(gomega.HaveOccurred())
+		test(config, 500, "lookup with uid 500")
+
+		paths.uid = 0
+		config, err = newLocked(&Options{}, paths)
+		gomega.Expect(err).ToNot(gomega.HaveOccurred())
+		test(config, 0, "lookup with uid 0 (root)")
+	})
+})