cmd/create: Require -y to pull an image when not connected to a terminal

It doesn't make sense to show the image download prompt when the
standard input or output stream is redirected to something other than a
terminal device.

During such non-interactive use, there's no way for the user to see the
prompt and the size of the image and then make a decision based on them.
The decision has to be made differently and earlier.  The user will
either never download or always download or will use 'skopeo inspect'
to decide for themself.

Secondly, when the input and output are not connected to a terminal, the
terminal escape sequences and the terminal-specific ioctl(2) requests
used to show the prompt won't work anyway.

Some changes by Debarshi Ray.

containers#1428

src/cmd/create.go

@@ -730,6 +730,16 @@ func pullImage(image, release, authFile string) (bool, error) {
 	}
 
 	if promptForDownload {
+		if !term.IsTerminal(os.Stdin) || !term.IsTerminal(os.Stdout) {
+			var builder strings.Builder
+			fmt.Fprintf(&builder, "image required to create toolbox container.\n")
+			fmt.Fprintf(&builder, "Use option '--assumeyes' to download the image.\n")
+			fmt.Fprintf(&builder, "Run '%s --help' for usage.", executableBase)
+
+			errMsg := builder.String()
+			return false, errors.New(errMsg)
+		}
+
 		shouldPullImage = showPromptForDownload(imageFull)
 	}
 

test/system/101-create.bats

@@ -52,6 +52,18 @@ teardown() {
   assert_success
 }
 
+@test "create: Try without --assumeyes" {
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" create
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: image required to create toolbox container."
+  assert_line --index 1 "Use option '--assumeyes' to download the image."
+  assert_line --index 2 "Run 'toolbox --help' for usage."
+  assert [ ${#stderr_lines[@]} -eq 3 ]
+}
+
 @test "create: Try with an invalid custom name (using positional argument)" {
   run "$TOOLBOX" --assumeyes create "ß[email protected]@m€"
 
@@ -83,6 +95,21 @@ teardown() {
   assert [ ${#lines[@]} -eq 4 ]
 }
 
+@test "create: Try with an invalid custom image (using --assumeyes)" {
+  local image="ß[email protected]@m€"
+
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" --assumeyes create --image "$image"
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: invalid argument for '--image'"
+  assert_line --index 1 "Container name $image generated from image is invalid."
+  assert_line --index 2 "Container names must match '[a-zA-Z0-9][a-zA-Z0-9_.-]*'."
+  assert_line --index 3 "Run 'toolbox --help' for usage."
+  assert [ ${#stderr_lines[@]} -eq 4 ]
+}
+
 @test "create: Arch Linux" {
   pull_distro_image arch latest
 
@@ -211,6 +238,18 @@ teardown() {
 }
 
 @test "create: Try a non-existent image" {
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" create --image foo.org/bar
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: image required to create toolbox container."
+  assert_line --index 1 "Use option '--assumeyes' to download the image."
+  assert_line --index 2 "Run 'toolbox --help' for usage."
+  assert [ ${#stderr_lines[@]} -eq 3 ]
+}
+
+@test "create: Try a non-existent image (using --assumeyes)" {
   run "$TOOLBOX" --assumeyes create --image foo.org/bar
 
   assert_failure
@@ -639,6 +678,17 @@ teardown() {
 }
 
 @test "create: Try using both --distro and --image" {
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" create --distro fedora --image fedora-toolbox:34
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: options --distro and --image cannot be used together"
+  assert_line --index 1 "Run 'toolbox --help' for usage."
+  assert [ ${#stderr_lines[@]} -eq 2 ]
+}
+
+@test "create: Try using both --distro and --image (using --assumeyes)" {
   pull_distro_image fedora 34
 
   run "$TOOLBOX" --assumeyes create --distro fedora --image fedora-toolbox:34
@@ -650,6 +700,17 @@ teardown() {
 }
 
 @test "create: Try using both --image and --release" {
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" create --image fedora-toolbox:34 --release 34
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: options --image and --release cannot be used together"
+  assert_line --index 1 "Run 'toolbox --help' for usage."
+  assert [ ${#lines[@]} -eq 2 ]
+}
+
+@test "create: Try using both --image and --release (using --assumeyes)" {
   pull_distro_image fedora 34
 
   run "$TOOLBOX" --assumeyes create --image fedora-toolbox:34 --release 34
@@ -672,6 +733,20 @@ teardown() {
   assert [ ${#lines[@]} -eq 3 ]
 }
 
+@test "create: Try a non-existent authentication file (using --assumeyes)" {
+  local file="$BATS_RUN_TMPDIR/non-existent-file"
+
+  run --keep-empty-lines --separate-stderr "$TOOLBOX" --assumeyes create --authfile "$file"
+
+  assert_failure
+  assert [ ${#lines[@]} -eq 0 ]
+  lines=("${stderr_lines[@]}")
+  assert_line --index 0 "Error: file $file not found"
+  assert_line --index 1 "'podman login' can be used to create the file."
+  assert_line --index 2 "Run 'toolbox --help' for usage."
+  assert [ ${#stderr_lines[@]} -eq 3 ]
+}
+
 @test "create: With a custom image that needs an authentication file" {
   local authfile="$BATS_RUN_TMPDIR/authfile"
   local image="fedora-toolbox:34"