Add multi-platform build support

app/src/main/java/io/seqera/wave/cli/App.java

@@ -126,7 +126,7 @@ public class App implements Runnable {
     @Option(names = {"--freeze", "-F"}, paramLabel = "false",  description = "Request a container freeze.")
     private boolean freeze;
 
-    @Option(names = {"--platform"}, paramLabel = "''", description = "Platform to be used for the container build. One of: linux/amd64, linux/arm64.")
+    @Option(names = {"--platform"}, paramLabel = "''", description = "Platform to be used for the container build: linux/amd64, linux/arm64, or both separated by comma for multi-platform builds.")
     private String platform;
 
     @Option(names = {"--await"}, paramLabel = "false", arity = "0..1", description = "Await the container build to be available. you can provide a timeout like --await 10m or 2s, by default its 15 minutes.")
@@ -420,9 +420,26 @@ protected void validateArgs() {
         if( dryRun && await != null )
             throw new IllegalCliArgumentException("Options --dry-run and --await conflicts each other");
 
-        if( !isEmpty(platform) && !VALID_PLATFORMS.contains(platform) )
-            throw new IllegalCliArgumentException(String.format("Unsupported container platform: '%s'", platform));
+        if( !isEmpty(platform) ) {
+            for( String p : platform.split(",") ) {
+                if( !VALID_PLATFORMS.contains(p.trim()) )
+                    throw new IllegalCliArgumentException(String.format("Unsupported container platform: '%s'", platform));
+            }
+        }
+
+        if( isMultiPlatform() && singularity )
+            throw new IllegalCliArgumentException("Multi-platform builds are not supported for Singularity format");
+
+        if( isMultiPlatform() && mirror )
+            throw new IllegalCliArgumentException("Multi-platform builds and --mirror conflict each other");
+
+        if( isMultiPlatform() && !isEmpty(image) && isEmpty(containerFile) && condaPackages==null && isEmpty(condaFile) && cranPackages==null )
+            throw new IllegalCliArgumentException("Multi-platform builds require a container file or packages to build");
+
+    }
 
+    private boolean isMultiPlatform() {
+        return !isEmpty(platform) && platform.contains(",");
     }
 
     protected Client client() {

app/src/main/resources/io/seqera/wave/cli/usage-examples.txt

@@ -9,9 +9,12 @@ Examples:
   # Build a container based on Conda packages
   wave --conda-package bamtools=2.5.2 --conda-package samtools=1.17
 
-  # Build a container based on Conda packages using arm64 architecture
+  # Build a container based on Conda packages using arm64 CPU architecture
   wave --conda-package fastp --platform linux/arm64
 
+  # Build a container based on Conda packages using both amd64 and arm64 CPU architectures
+  wave --conda-package fastp --platform linux/amd64,linux/arm64
+
   # Build a container based on Conda lock file served via prefix.dev service
   wave --conda-package https://prefix.dev/envs/pditommaso/wave/conda-lock.yml
 

app/src/test/groovy/io/seqera/wave/cli/AppTest.groovy

@@ -631,6 +631,60 @@ class AppTest extends Specification {
         e.getMessage() == "Option --mirror and requires the use of a build repository"
     }
 
+    def 'should set multi-platform via --platform' () {
+        given:
+        def app = new App()
+        String[] args = ["--platform", "linux/amd64,linux/arm64", "-f", "Dockerfile"]
+
+        when:
+        new CommandLine(app).parseArgs(args)
+
+        then:
+        app.@platform == "linux/amd64,linux/arm64"
+    }
+
+    def 'should fail when specifying multi-platform and singularity' () {
+        given:
+        def app = new App()
+        String[] args = ["--platform", "linux/amd64,linux/arm64", "--singularity", "--freeze", "-f", "Dockerfile"]
+
+        when:
+        new CommandLine(app).parseArgs(args)
+        app.validateArgs()
+
+        then:
+        def e = thrown(IllegalCliArgumentException)
+        e.getMessage() == "Multi-platform builds are not supported for Singularity format"
+    }
+
+    def 'should fail when specifying multi-platform and mirror' () {
+        given:
+        def app = new App()
+        String[] args = ["--platform", "linux/amd64,linux/arm64", "--mirror", "--image", "foo", "--build-repo", "bar", "--tower-token", "tok"]
+
+        when:
+        new CommandLine(app).parseArgs(args)
+        app.validateArgs()
+
+        then:
+        def e = thrown(IllegalCliArgumentException)
+        e.getMessage() == "Multi-platform builds and --mirror conflict each other"
+    }
+
+    def 'should fail when specifying multi-platform with only image' () {
+        given:
+        def app = new App()
+        String[] args = ["--platform", "linux/amd64,linux/arm64", "--image", "ubuntu:latest"]
+
+        when:
+        new CommandLine(app).parseArgs(args)
+        app.validateArgs()
+
+        then:
+        def e = thrown(IllegalCliArgumentException)
+        e.getMessage() == "Multi-platform builds require a container file or packages to build"
+    }
+
     @Unroll
     def 'should check service version'() {
         given: