Add basic rootless podman support

The implementation is mostly borrowed from the rootless docker strategy.

Author: SoMuchForSubtlety

core/src/main/java/org/testcontainers/dockerclient/RootlessPodmanClientProviderStrategy.java

@@ -0,0 +1,95 @@
+package org.testcontainers.dockerclient;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.lang3.SystemUtils;
+import org.jetbrains.annotations.Nullable;
+
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Optional;
+
+/**
+ *
+ * @deprecated this class is used by the SPI and should not be used directly
+ */
+@Deprecated
+@Slf4j
+public final class RootlessPodmanClientProviderStrategy extends DockerClientProviderStrategy {
+
+    public static final int PRIORITY = UnixSocketClientProviderStrategy.PRIORITY + 1;
+
+    @Getter(lazy = true)
+    @Nullable
+    private final Path socketPath = resolveSocketPath();
+
+    private Path resolveSocketPath() {
+        return tryEnv()
+            .orElseGet(() -> {
+                Path implicitPath = Paths.get("/run/user/" + LibC.INSTANCE.getuid());
+                return tryFolder(implicitPath).orElse(null);
+            });
+    }
+
+    private Optional<Path> tryEnv() {
+        String xdgRuntimeDir = System.getenv("XDG_RUNTIME_DIR");
+        if (StringUtils.isBlank(xdgRuntimeDir)) {
+            log.debug("$XDG_RUNTIME_DIR is not set.");
+            return Optional.empty();
+        }
+        Path path = Paths.get(xdgRuntimeDir);
+        if (!Files.exists(path)) {
+            log.debug("$XDG_RUNTIME_DIR is set to '{}' but the folder does not exist.", path);
+            return Optional.empty();
+        }
+        Path podmanSocketPath = path.resolve("podman/podman.sock");
+        if (!Files.exists(podmanSocketPath)) {
+            log.debug("$XDG_RUNTIME_DIR is set but '{}' does not exist.", podmanSocketPath);
+            return Optional.empty();
+        }
+        return Optional.of(podmanSocketPath);
+    }
+
+    private Optional<Path> tryFolder(Path path) {
+        if (!Files.exists(path)) {
+            log.debug("'{}' does not exist.", path);
+            return Optional.empty();
+        }
+        Path podmanSocketPath = path.resolve("podman/podman.sock");
+        if (!Files.exists(podmanSocketPath)) {
+            log.debug("'{}' does not exist.", podmanSocketPath);
+            return Optional.empty();
+        }
+        return Optional.of(podmanSocketPath);
+    }
+
+    @Override
+    public TransportConfig getTransportConfig() throws InvalidConfigurationException {
+        return TransportConfig.builder().dockerHost(URI.create("unix://" + getSocketPath().toString())).build();
+    }
+
+    @Override
+    protected boolean isApplicable() {
+        return SystemUtils.IS_OS_LINUX && getSocketPath() != null && Files.exists(getSocketPath());
+    }
+
+    @Override
+    public String getDescription() {
+        return "Rootless Podman accessed via Unix socket (" + getSocketPath() + ")";
+    }
+
+    @Override
+    protected int getPriority() {
+        return PRIORITY;
+    }
+
+    private interface LibC extends Library {
+        LibC INSTANCE = Native.loadLibrary("c", LibC.class);
+        int getuid();
+    }
+}

core/src/main/resources/META-INF/services/org.testcontainers.dockerclient.DockerClientProviderStrategy

@@ -3,3 +3,4 @@ org.testcontainers.dockerclient.UnixSocketClientProviderStrategy
 org.testcontainers.dockerclient.DockerMachineClientProviderStrategy
 org.testcontainers.dockerclient.NpipeSocketClientProviderStrategy
 org.testcontainers.dockerclient.RootlessDockerClientProviderStrategy
+org.testcontainers.dockerclient.RootlessPodmanClientProviderStrategy

core/src/test/java/org/testcontainers/DockerRegistryContainer.java

@@ -100,7 +100,7 @@ public DockerImageName createImage(String originalImage, String tag) {
             .withTag(tag);
 
         // push the image to the registry
-        client.tagImageCmd(dummyImageId, imageName.asCanonicalNameString(), tag).exec();
+        client.tagImageCmd(dummyImageId, imageName.getUnversionedPart(), tag).exec();
 
         client
             .pushImageCmd(imageName.asCanonicalNameString())