Merge branch 'stable-3.8' into stable-3.9 * stable-3.8: Rename config.md to metrics.md Add the ability to fail healthcheck by creating a fail file Revert "Adapt list projects tests to ListProjectsImpl new type" Change-Id: Icb283845635c6dd0f73c9bf390c091ceea8b5c33

diff --git a/README.md b/README.md
index 8be0b33..bd49524 100644
--- a/README.md
+++ b/README.md

@@ -126,6 +126,25 @@
 }
 ```
 
+It's also possible to artificially make the healthcheck fail by placing a file
+at a configurable path specified like:
+
+```
+[healtcheck]
+  failFileFlaPath="data/healthcheck/fail"
+```
+
+This will make the healthcheck endpoint return 500 even if the node is otherwise
+healthy. This is useful when a node needs to be removed from the pool of
+available Gerrit instance while it undergoes maintenance.
+
+**NOTE**: If the path starts with `/` then even paths outside of Gerrit's home
+will be checked. If the path starts WITHOUT `/` then the path is relative to
+Gerrit's home.
+
+**NOTE**: The file needs to be a real file rather than a symlink.
+
+
 ## Metrics
 
 As for all other endpoints in Gerrit, some metrics are automatically emitted when the  `/config/server/healthcheck~status`
@@ -134,4 +153,4 @@
 Some additional metrics are also produced to give extra insights on their result about results and latency of healthcheck
 sub component, such as jgit, reviewdb, etc.
 
-More information can be found in the [config.md](resources/Documentation/config.md) file.
+More information can be found in the [metrics.md](resources/Documentation/metrics.md) file.

diff --git a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckConfig.java b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckConfig.java
index 651dbe9..1dc143c 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckConfig.java

@@ -47,6 +47,7 @@
   private static final int ACTIVE_WORKERS_THRESHOLD_DEFAULT = 80;
   private static final String USERNAME_DEFAULT = "healthcheck";
   private static final String PASSWORD_DEFAULT = "";
+  private static final String FAIL_FILE_FLAG_DEFAULT = "data/healthcheck/fail";
   private static final boolean HEALTH_CHECK_ENABLED_DEFAULT = true;
   private final AllProjectsName allProjectsName;
   private final AllUsersName allUsersName;
@@ -135,6 +136,10 @@
     return getStringWithFallback("password", healthCheckName, PASSWORD_DEFAULT);
   }
 
+  public String getFailFileFlagPath() {
+    return getStringWithFallback("failFileFlagPath", null, FAIL_FILE_FLAG_DEFAULT);
+  }
+
   public boolean healthCheckEnabled(String healthCheckName) {
     if (isReplica && HEALTH_CHECK_DISABLED_FOR_REPLICAS.contains(healthCheckName)) {
       return false;

diff --git a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/api/HealthCheckStatusEndpoint.java b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/api/HealthCheckStatusEndpoint.java
index 2d5f7de..6819ae1 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/healthcheck/api/HealthCheckStatusEndpoint.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/healthcheck/api/HealthCheckStatusEndpoint.java

@@ -18,9 +18,14 @@
 import com.google.gerrit.server.config.ConfigResource;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import com.googlesource.gerrit.plugins.healthcheck.HealthCheckConfig;
 import com.googlesource.gerrit.plugins.healthcheck.check.GlobalHealthCheck;
 import com.googlesource.gerrit.plugins.healthcheck.check.HealthCheck;
 import com.googlesource.gerrit.plugins.healthcheck.check.HealthCheck.Result;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.Map;
 import javax.servlet.http.HttpServletResponse;
 
@@ -29,14 +34,21 @@
 
   private final GlobalHealthCheck healthChecks;
 
+  private final String failedFileFlagPath;
+
   @Inject
-  public HealthCheckStatusEndpoint(GlobalHealthCheck healthChecks) {
+  public HealthCheckStatusEndpoint(GlobalHealthCheck healthChecks, HealthCheckConfig config) {
     this.healthChecks = healthChecks;
+    this.failedFileFlagPath = config.getFailFileFlagPath();
   }
 
   @Override
   public Response<Map<String, Object>> apply(ConfigResource resource)
       throws AuthException, BadRequestException, ResourceConflictException, Exception {
+    if (failFlagFileExists()) {
+      return Response.withStatusCode(
+          HttpServletResponse.SC_INTERNAL_SERVER_ERROR, Map.of("reason", "Fail Flag File exists"));
+    }
     HealthCheck.StatusSummary globalHealthCheckStatus = healthChecks.run();
 
     Map<String, Object> result = globalHealthCheckStatus.subChecks;
@@ -50,4 +62,13 @@
         ? HttpServletResponse.SC_INTERNAL_SERVER_ERROR
         : HttpServletResponse.SC_OK;
   }
+
+  private boolean failFlagFileExists() throws IOException {
+    File file = new File(failedFileFlagPath);
+    try (InputStream targetStream = new FileInputStream(file)) {
+      return true;
+    } catch (Exception e) {
+      return false;
+    }
+  }
 }

diff --git a/src/test/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckIT.java b/src/test/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckIT.java
index 4c646e5..17f1e10 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/healthcheck/HealthCheckIT.java

@@ -32,7 +32,9 @@
 import com.google.inject.AbstractModule;
 import com.google.inject.Key;
 import com.googlesource.gerrit.plugins.healthcheck.check.HealthCheckNames;
+import java.io.File;
 import java.io.IOException;
+import javax.servlet.http.HttpServletResponse;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.junit.Before;
 import org.junit.Test;
@@ -46,6 +48,7 @@
   Gson gson = new Gson();
   HealthCheckConfig config;
   String healthCheckUriPath;
+  String failFilePath;
 
   public static class TestModule extends AbstractModule {
 
@@ -62,6 +65,9 @@
     super.setUpTestPlugin();
 
     config = plugin.getSysInjector().getInstance(HealthCheckConfig.class);
+    failFilePath = "/tmp/fail";
+    new File(failFilePath).delete();
+
     int numChanges = config.getLimit(HealthCheckNames.QUERYCHANGES);
     for (int i = 0; i < numChanges; i++) {
       createChange("refs/for/master");
@@ -205,6 +211,25 @@
     assertCheckResult(getResponseJson(resp), ACTIVEWORKERS, "passed");
   }
 
+  @Test
+  public void shouldReturnFailedIfFailFlagFileExists() throws Exception {
+    setFailFlagFilePath(failFilePath);
+    createFailFileFlag(failFilePath);
+    getHealthCheckStatus();
+    RestResponse resp = getHealthCheckStatus();
+    resp.assertStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+
+    JsonObject respBody = getResponseJson(resp);
+    assertThat(respBody.has("reason")).isTrue();
+    assertThat(respBody.get("reason").getAsString()).isEqualTo("Fail Flag File exists");
+  }
+
+  private void createFailFileFlag(String path) throws IOException {
+    File file = new File(path);
+    file.createNewFile();
+    file.deleteOnExit();
+  }
+
   private RestResponse getHealthCheckStatus() throws IOException {
     return adminRestSession.get(healthCheckUriPath);
   }
@@ -224,6 +249,10 @@
     config.fromText(String.format("[healthcheck \"%s\"]\n" + "enabled = false", check));
   }
 
+  private void setFailFlagFilePath(String path) throws ConfigInvalidException {
+    config.fromText(String.format("[healthcheck]\n" + "failFileFlagPath = %s", path));
+  }
+
   private JsonObject getResponseJson(RestResponse resp) throws IOException {
     JsonObject respPayload = gson.fromJson(resp.getReader(), JsonObject.class);
     return respPayload;

diff --git a/src/test/java/com/googlesource/gerrit/plugins/healthcheck/ProjectsListHealthCheckTest.java b/src/test/java/com/googlesource/gerrit/plugins/healthcheck/ProjectsListHealthCheckTest.java
index 293c596..610284c 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/healthcheck/ProjectsListHealthCheckTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/healthcheck/ProjectsListHealthCheckTest.java

@@ -85,8 +85,7 @@
 
   private Provider<ListProjects> getFailingProjectList() {
     return Providers.of(
-        new ListProjectsImpl(
-            null, null, null, null, null, null, null, null, null, gerritConfig, null) {
+        new ListProjectsImpl(null, null, null, null, null, null, null, null, null, gerritConfig, null) {
 
           @Override
           public SortedMap<String, ProjectInfo> apply() throws BadRequestException {
@@ -97,8 +96,7 @@
 
   private Provider<ListProjects> getWorkingProjectList(long execTime) {
     return Providers.of(
-        new ListProjectsImpl(
-            null, null, null, null, null, null, null, null, null, gerritConfig, null) {
+        new ListProjectsImpl(null, null, null, null, null, null, null, null, null, gerritConfig, null) {
 
           @Override
           public SortedMap<String, ProjectInfo> apply() throws BadRequestException {