fix mandatory parameter in login/logout

fix #5146
Insted of using a registry as mandatory parameter, this path allows podman to use the first registry from registries.conf.

Signed-off-by: Qi Wang <qiwan@redhat.com>

5 files changed, 72 insertions, 16 deletions

diff --git a/cmd/podman/login.go b/cmd/podman/login.go
index 369e0da16..e5ff273b8 100644
--- a/cmd/podman/login.go
+++ b/cmd/podman/login.go
@@ -12,6 +12,7 @@ import (
 	"github.com/containers/image/v5/types"
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/libpod/image"
+	"github.com/containers/libpod/pkg/registries"
 	"github.com/docker/docker-credential-helpers/credentials"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -67,10 +68,19 @@ func loginCmd(c *cliconfig.LoginValues) error {
 	if len(args) > 1 {
 		return errors.Errorf("too many arguments, login takes only 1 argument")
 	}
+	var server string
 	if len(args) == 0 {
-		return errors.Errorf("please specify a registry to login to")
+		registriesFromFile, err := registries.GetRegistries()
+		if err != nil || len(registriesFromFile) == 0 {
+			return errors.Errorf("please specify a registry to login to")
+		}
+
+		server = registriesFromFile[0]
+		logrus.Debugf("registry not specified, default to the first registry %q from registries.conf", server)
+
+	} else {
+		server = registryFromFullName(scrubServer(args[0]))
 	}
-	server := registryFromFullName(scrubServer(args[0]))
 
 	sc := image.GetSystemContext("", c.Authfile, false)
 	if c.Flag("tls-verify").Changed {
diff --git a/cmd/podman/logout.go b/cmd/podman/logout.go
index 4a113b1d0..dec6822cf 100644
--- a/cmd/podman/logout.go
+++ b/cmd/podman/logout.go
@@ -8,7 +8,9 @@ import (
 	"github.com/containers/image/v5/pkg/docker/config"
 	"github.com/containers/libpod/cmd/podman/cliconfig"
 	"github.com/containers/libpod/cmd/podman/shared"
+	"github.com/containers/libpod/pkg/registries"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
@@ -51,10 +53,16 @@ func logoutCmd(c *cliconfig.LogoutValues) error {
 	if len(args) > 1 {
 		return errors.Errorf("too many arguments, logout takes at most 1 argument")
 	}
+	var server string
 	if len(args) == 0 && !c.All {
-		return errors.Errorf("registry must be given")
+		registriesFromFile, err := registries.GetRegistries()
+		if err != nil || len(registriesFromFile) == 0 {
+			return errors.Errorf("no registries found in registries.conf, a registry must be provided")
+		}
+
+		server = registriesFromFile[0]
+		logrus.Debugf("registry not specified, default to the first registry %q from registries.conf", server)
 	}
-	var server string
 	if len(args) == 1 {
 		server = scrubServer(args[0])
 	}
diff --git a/docs/source/markdown/podman-login.1.md b/docs/source/markdown/podman-login.1.md
index 8a84d359d..a69b311eb 100644
--- a/docs/source/markdown/podman-login.1.md
+++ b/docs/source/markdown/podman-login.1.md
@@ -4,11 +4,12 @@
 podman\-login - Login to a container registry
 
 ## SYNOPSIS
-**podman login** [*options*] *registry*
+**podman login** [*options*] [*registry*]
 
 ## DESCRIPTION
 **podman login** logs into a specified registry server with the correct username
-and password. **podman login** reads in the username and password from STDIN.
+and password. If the registry is not specified, the first registry under [registries.search]
+from registries.conf will be used. **podman login** reads in the username and password from STDIN.
 The username and password can also be set using the **username** and **password** flags.
 The path of the authentication file can be specified by the user by setting the **authfile**
 flag. The default path used is **${XDG\_RUNTIME\_DIR}/containers/auth.json**.
@@ -17,7 +18,7 @@ flag. The default path used is **${XDG\_RUNTIME\_DIR}/containers/auth.json**.
 
 **podman login [GLOBAL OPTIONS]**
 
-**podman login [OPTIONS] REGISTRY [GLOBAL OPTIONS]**
+**podman login [OPTIONS] [REGISTRY] [GLOBAL OPTIONS]**
 
 ## OPTIONS
 
diff --git a/docs/source/markdown/podman-logout.1.md b/docs/source/markdown/podman-logout.1.md
index 01dc52ecd..8b9f75760 100644
--- a/docs/source/markdown/podman-logout.1.md
+++ b/docs/source/markdown/podman-logout.1.md
@@ -8,7 +8,8 @@ podman\-logout - Logout of a container registry
 
 ## DESCRIPTION
 **podman logout** logs out of a specified registry server by deleting the cached credentials
-stored in the **auth.json** file. The path of the authentication file can be overridden by the user by setting the **authfile** flag.
+stored in the **auth.json** file. If the registry is not specified, the first registry under [registries.search]
+from registries.conf will be used. The path of the authentication file can be overridden by the user by setting the **authfile** flag.
 The default path used is **${XDG\_RUNTIME\_DIR}/containers/auth.json**.
 All the cached credentials can be removed by setting the **all** flag.
 
diff --git a/test/e2e/login_logout_test.go b/test/e2e/login_logout_test.go
index 78c9b52d9..42698d270 100644
--- a/test/e2e/login_logout_test.go
+++ b/test/e2e/login_logout_test.go
@@ -19,14 +19,15 @@ import (
 
 var _ = Describe("Podman login and logout", func() {
 	var (
-		tempdir    string
-		err        error
-		podmanTest *PodmanTestIntegration
-		authPath   string
-		certPath   string
-		port       int
-		server     string
-		testImg    string
+		tempdir                  string
+		err                      error
+		podmanTest               *PodmanTestIntegration
+		authPath                 string
+		certPath                 string
+		port                     int
+		server                   string
+		testImg                  string
+		registriesConfWithSearch []byte
 	)
 
 	BeforeEach(func() {
@@ -64,6 +65,9 @@ var _ = Describe("Podman login and logout", func() {
 		f.Sync()
 		port = 4999 + config.GinkgoConfig.ParallelNode
 		server = strings.Join([]string{"localhost", strconv.Itoa(port)}, ":")
+
+		registriesConfWithSearch = []byte(fmt.Sprintf("[registries.search]\nregistries = ['%s']", server))
+
 		testImg = strings.Join([]string{server, "test-apline"}, "/")
 
 		os.MkdirAll(filepath.Join("/etc/containers/certs.d", server), os.ModePerm)
@@ -113,6 +117,38 @@ var _ = Describe("Podman login and logout", func() {
 		Expect(session).To(ExitWithError())
 	})
 
+	It("podman login and logout without registry parameter", func() {
+		SkipIfRootless()
+
+		registriesConf, err := ioutil.TempFile("", "TestLoginWithoutParameter")
+		Expect(err).To(BeNil())
+		defer registriesConf.Close()
+		defer os.Remove(registriesConf.Name())
+
+		err = ioutil.WriteFile(registriesConf.Name(), []byte(registriesConfWithSearch), os.ModePerm)
+		Expect(err).To(BeNil())
+
+		// Environment is per-process, so this looks very unsafe; actually it seems fine because tests are not
+		// run in parallel unless they opt in by calling t.Parallel().  So don’t do that.
+		oldRCP, hasRCP := os.LookupEnv("REGISTRIES_CONFIG_PATH")
+		defer func() {
+			if hasRCP {
+				os.Setenv("REGISTRIES_CONFIG_PATH", oldRCP)
+			} else {
+				os.Unsetenv("REGISTRIES_CONFIG_PATH")
+			}
+		}()
+		os.Setenv("REGISTRIES_CONFIG_PATH", registriesConf.Name())
+
+		session := podmanTest.Podman([]string{"login", "-u", "podmantest", "-p", "test"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To((Equal(0)))
+
+		session = podmanTest.Podman([]string{"logout"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+	})
+
 	It("podman login and logout with flag --authfile", func() {
 		SkipIfRootless()
 		authFile := filepath.Join(podmanTest.TempDir, "auth.json")