Allow specifying a different shell command other than /bin/sh

README.md

@@ -249,6 +249,22 @@ There might be cases, where you need to have the agent pod run inside a differen
 For example you may need the agent to run inside an `ephemeral` namespace for the sake of testing.
 For those cases you can explicitly configure a namespace either using the ui or the pipeline.
 
+#### Specifying a different shell command other than /bin/sh
+
+By default, the shell command is /bin/sh. In some case, you would like to use another shell command like /bin/bash.
+
+```groovy
+podTemplate(label: my-label) {
+  node(my-label) {
+    stage('Run specific shell') {
+      container(name:'mycontainer', shell:'/bin/bash') {
+        sh 'echo hello world'
+      }
+    }
+  }
+}
+```
+
 ## Container Configuration
 When configuring a container in a pipeline podTemplate the following options are available:
 

src/main/java/org/csanchez/jenkins/plugins/kubernetes/ContainerTemplate.java

@@ -4,6 +4,8 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
 
 import org.apache.commons.lang.StringUtils;
 import org.csanchez.jenkins.plugins.kubernetes.model.TemplateEnvVar;
@@ -50,6 +52,7 @@ public class ContainerTemplate extends AbstractDescribableImpl<ContainerTemplate
     private String resourceLimitCpu;
 
     private String resourceLimitMemory;
+    private String shell;
 
     private final List<TemplateEnvVar> envVars = new ArrayList<>();
     private List<PortMapping> ports = new ArrayList<PortMapping>();
@@ -214,6 +217,18 @@ public void setResourceRequestCpu(String resourceRequestCpu) {
         this.resourceRequestCpu = resourceRequestCpu;
     }
 
+    public Map<String,Object> getAsArgs() {
+        Map<String,Object> argMap = new TreeMap<>();
+
+        argMap.put("name", name);
+
+        if (!StringUtils.isEmpty(shell)) {
+            argMap.put("shell", shell);
+        }
+
+        return argMap;
+    }
+
     @Extension
     @Symbol("containerTemplate")
     public static class DescriptorImpl extends Descriptor<ContainerTemplate> {
@@ -250,4 +265,13 @@ public String toString() {
                 (livenessProbe == null ? "" : ", livenessProbe=" + livenessProbe) +
                 '}';
     }
+
+    public String getShell() {
+        return shell;
+    }
+
+    @DataBoundSetter
+    public void setShell(String shell) {
+        this.shell = shell;
+    }
 }

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/ContainerExecDecorator.java

@@ -42,7 +42,6 @@
 import org.csanchez.jenkins.plugins.kubernetes.pipeline.proc.CachedProc;
 import org.csanchez.jenkins.plugins.kubernetes.pipeline.proc.DeadProc;
 
-
 import edu.umd.cs.findbugs.annotations.CheckForNull;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import hudson.EnvVars;
@@ -77,6 +76,7 @@ public class ContainerExecDecorator extends LauncherDecorator implements Seriali
     private static final String COOKIE_VAR = "JENKINS_SERVER_COOKIE";
 
     private static final Logger LOGGER = Logger.getLogger(ContainerExecDecorator.class.getName());
+    private static final String DEFAULT_SHELL="/bin/sh";
 
     private transient KubernetesClient client;
 
@@ -93,6 +93,7 @@ public class ContainerExecDecorator extends LauncherDecorator implements Seriali
     private EnvVars globalVars;
     private FilePath ws;
     private EnvVars rcEnvVars;
+    private String shell;
 
     public ContainerExecDecorator() {
     }
@@ -105,6 +106,7 @@ public ContainerExecDecorator(KubernetesClient client, String podName, String co
         this.containerName = containerName;
         this.environmentExpander = environmentExpander;
         this.ws = ws;
+        this.shell = DEFAULT_SHELL;
     }
 
     @Deprecated
@@ -196,6 +198,14 @@ public void setWs(FilePath ws) {
         this.ws = ws;
     }
 
+    public String getShell() {
+        return shell == null? DEFAULT_SHELL:shell;
+    }
+
+    public void setShell(String shell) {
+        this.shell = shell;
+    }
+
     @Override
     public Launcher decorate(final Launcher launcher, final Node node) {
         return new Launcher.DecoratedLauncher(launcher) {
@@ -309,7 +319,7 @@ public void onClose(int i, String s) {
 
                 ExecWatch watch;
                 try {
-                    watch = execable.exec("/bin/sh");
+                    watch = execable.exec(getShell());
                 } catch (KubernetesClientException e) {
                     if (e.getCause() instanceof InterruptedException) {
                         throw new IOException("JENKINS-40825: interrupted while starting websocket connection", e);

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/ContainerStep.java

@@ -8,6 +8,7 @@
 import org.jenkinsci.plugins.workflow.steps.StepDescriptor;
 import org.jenkinsci.plugins.workflow.steps.StepExecution;
 import org.kohsuke.stapler.DataBoundConstructor;
+import org.kohsuke.stapler.DataBoundSetter;
 
 import com.google.common.collect.ImmutableSet;
 
@@ -21,6 +22,7 @@ public class ContainerStep extends Step implements Serializable {
     private static final long serialVersionUID = 5588861066775717487L;
 
     private final String name;
+    private String shell;
 
     @DataBoundConstructor
     public ContainerStep(String name) {
@@ -31,6 +33,15 @@ public String getName() {
         return name;
     }
 
+    @DataBoundSetter
+    public void setShell(String shell){
+        this.shell = shell;
+    }
+
+    public String getShell() {
+        return shell;
+    }
+
     @Override
     public StepExecution start(StepContext context) throws Exception {
         return new ContainerStepExecution(this, context);

src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/ContainerStepExecution.java

@@ -63,6 +63,7 @@ public void onResume() {
     public boolean start() throws Exception {
         LOGGER.log(Level.FINE, "Starting container step.");
         String containerName = step.getName();
+        String shell = step.getShell();
 
         KubernetesNodeContext nodeContext = new KubernetesNodeContext(getContext());
         client = nodeContext.connectToCloud();
@@ -94,6 +95,7 @@ public boolean start() throws Exception {
         decorator.setWs(getContext().get(FilePath.class));
         decorator.setGlobalVars(globalVars);
         decorator.setRunContextEnvVars(rcEnvVars);
+        decorator.setShell(shell);
         getContext().newBodyInvoker()
                 .withContext(BodyInvoker
                         .mergeLauncherDecorators(getContext().get(LauncherDecorator.class), decorator))

src/main/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/KubernetesDeclarativeAgentScript.groovy

@@ -50,7 +50,7 @@ public class KubernetesDeclarativeAgentScript extends DeclarativeAgentScript<Kub
                                 script.checkout script.scm
                             }
                         }
-                        script.container(describable.containerTemplate.name) {
+                        script.container(describable.containerTemplate.asArgs) {
                             body.call()
                         }
                     }

src/test/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/KubernetesPipelineTest.java

@@ -40,6 +40,7 @@
 import org.junit.rules.TemporaryFolder;
 import org.jvnet.hudson.test.JenkinsRuleNonLocalhost;
 
+import hudson.model.Result;
 import io.fabric8.kubernetes.api.model.NamespaceBuilder;
 import io.fabric8.kubernetes.client.KubernetesClient;
 
@@ -83,6 +84,16 @@ private boolean hasPodTemplateWithLabel(String label, List<PodTemplate> template
                 .anyMatch(label::equals);
     }
 
+    @Test
+    public void runInPodWithDifferentShell() throws Exception {
+        WorkflowJob p = r.jenkins.createProject(WorkflowJob.class, "p");
+        p.setDefinition(new CpsFlowDefinition(loadPipelineScript("runInPodWithDifferentShell.groovy"), true));
+        WorkflowRun b = p.scheduleBuild2(0).waitForStart();
+        assertNotNull(b);
+        r.assertBuildStatus(Result.FAILURE,r.waitForCompletion(b));
+        r.assertLogContains("/bin/bash: no such file or directory", b);
+    }
+
     @Test
     public void runInPodWithMultipleContainers() throws Exception {
         WorkflowJob p = r.jenkins.createProject(WorkflowJob.class, "p");

src/test/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/declarative.groovy

@@ -24,5 +24,12 @@ pipeline {
         }
       }
     }
+	stage('Run maven with a different shell') {
+		steps {
+		  container(name: 'maven', shell: '/bin/bash') {
+			sh 'mvn -version'
+		  }
+		}
+	  }
   }
 }

src/test/resources/org/csanchez/jenkins/plugins/kubernetes/pipeline/runInPodWithDifferentShell.groovy

@@ -0,0 +1,14 @@
+podTemplate(label: 'mypod', containers: [
+        containerTemplate(name: 'busybox', image: 'busybox', ttyEnabled: true, command: '/bin/cat'),
+    ]) {
+
+    node ('mypod') {
+      stage('Run') {
+        container(name:'busybox', shell: '/bin/bash') {
+          sh """
+            echo "Run BusyBox shell"
+          """
+        }
+      }
+    }
+}