chore: add .kokoro scripts

copy/paste all kokoro scripts from java-logging-logback.
replace the repo name in all .sh and .cfg

.kokoro/build.bat

@@ -0,0 +1,3 @@
+:: See documentation in type-shell-output.bat
+
+"C:\Program Files\Git\bin\bash.exe" %~dp0build.sh

.kokoro/build.sh

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+#!/bin/bash
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eo pipefail
+
+## Get the directory of the build script
+scriptDir=$(realpath $(dirname "${BASH_SOURCE[0]}"))
+## cd to the parent directory, i.e. the root of the git repo
+cd ${scriptDir}/..
+
+# include common functions
+source ${scriptDir}/common.sh
+
+# Print out Maven & Java version
+mvn -version
+echo ${JOB_TYPE}
+
+# attempt to install 3 times with exponential backoff (starting with 10 seconds)
+retry_with_backoff 3 10 \
+  mvn install -B -V -ntp \
+    -DskipTests=true \
+    -Dclirr.skip=true \
+    -Denforcer.skip=true \
+    -Dmaven.javadoc.skip=true \
+    -Dgcloud.download.skip=true \
+    -T 1C
+
+# if GOOGLE_APPLICATION_CREDENTIALS is specified as a relative path, prepend Kokoro root directory onto it
+if [[ ! -z "${GOOGLE_APPLICATION_CREDENTIALS}" && "${GOOGLE_APPLICATION_CREDENTIALS}" != /* ]]; then
+    export GOOGLE_APPLICATION_CREDENTIALS=$(realpath ${KOKORO_GFILE_DIR}/${GOOGLE_APPLICATION_CREDENTIALS})
+fi
+
+RETURN_CODE=0
+set +e
+
+case ${JOB_TYPE} in
+test)
+    mvn test -B -Dclirr.skip=true -Denforcer.skip=true
+    RETURN_CODE=$?
+    ;;
+lint)
+    mvn com.coveo:fmt-maven-plugin:check
+    RETURN_CODE=$?
+    ;;
+javadoc)
+    mvn javadoc:javadoc javadoc:test-javadoc
+    RETURN_CODE=$?
+    ;;
+integration)
+    mvn -B ${INTEGRATION_TEST_ARGS} \
+      -ntp \
+      -Penable-integration-tests \
+      -DtrimStackTrace=false \
+      -Dclirr.skip=true \
+      -Denforcer.skip=true \
+      -fae \
+      verify
+    RETURN_CODE=$?
+    ;;
+graalvm)
+    # Run Unit and Integration Tests with Native Image
+    mvn test -Pnative -Penable-integration-tests
+    RETURN_CODE=$?
+    ;;
+samples)
+    SAMPLES_DIR=samples
+    # only run ITs in snapshot/ on presubmit PRs. run ITs in all 3 samples/ subdirectories otherwise.
+    if [[ ! -z ${KOKORO_GITHUB_PULL_REQUEST_NUMBER} ]]
+    then
+      SAMPLES_DIR=samples/snapshot
+    fi
+
+    if [[ -f ${SAMPLES_DIR}/pom.xml ]]
+    then
+        for FILE in ${KOKORO_GFILE_DIR}/secret_manager/*-samples-secrets; do
+          [[ -f "$FILE" ]] || continue
+          source "$FILE"
+        done
+
+        pushd ${SAMPLES_DIR}
+        mvn -B \
+          -ntp \
+          -DtrimStackTrace=false \
+          -Dclirr.skip=true \
+          -Denforcer.skip=true \
+          -fae \
+          verify
+        RETURN_CODE=$?
+        popd
+    else
+        echo "no sample pom.xml found - skipping sample tests"
+    fi
+    ;;
+clirr)
+    mvn -B -Denforcer.skip=true clirr:check
+    RETURN_CODE=$?
+    ;;
+*)
+    ;;
+esac
+
+if [ "${REPORT_COVERAGE}" == "true" ]
+then
+  bash ${KOKORO_GFILE_DIR}/codecov.sh
+fi
+
+# fix output location of logs
+bash .kokoro/coerce_logs.sh
+
+if [[ "${ENABLE_FLAKYBOT}" == "true" ]]
+then
+    chmod +x ${KOKORO_GFILE_DIR}/linux_amd64/flakybot
+    ${KOKORO_GFILE_DIR}/linux_amd64/flakybot -repo=googleapis/java-logging-servlet-initializer
+fi
+
+echo "exiting with ${RETURN_CODE}"
+exit ${RETURN_CODE}

.kokoro/coerce_logs.sh

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+#!/bin/bash
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script finds and moves sponge logs so that they can be found by placer
+# and are not flagged as flaky by sponge.
+
+set -eo pipefail
+
+## Get the directory of the build script
+scriptDir=$(realpath $(dirname "${BASH_SOURCE[0]}"))
+## cd to the parent directory, i.e. the root of the git repo
+cd ${scriptDir}/..
+
+job=$(basename ${KOKORO_JOB_NAME})
+
+echo "coercing sponge logs..."
+for xml in `find . -name *-sponge_log.xml`
+do
+  class=$(basename ${xml} | cut -d- -f2)
+  dir=$(dirname ${xml})/${job}/${class}
+  text=$(dirname ${xml})/${class}-sponge_log.txt
+  mkdir -p ${dir}
+  mv ${xml} ${dir}/sponge_log.xml
+  mv ${text} ${dir}/sponge_log.txt
+done

.kokoro/common.cfg

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+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Download trampoline resources. These will be in ${KOKORO_GFILE_DIR}
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# All builds use the trampoline script to run in docker.
+build_file: "java-logging-servlet-initializer/.kokoro/trampoline.sh"
+
+# Tell the trampoline which build file to use.
+env_vars: {
+  key: "TRAMPOLINE_BUILD_FILE"
+  value: "github/java-logging-servlet-initializer/.kokoro/build.sh"
+}

.kokoro/common.sh

@@ -0,0 +1,58 @@
+#!/bin/bash
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+function retry_with_backoff {
+    attempts_left=$1
+    sleep_seconds=$2
+    shift 2
+    command=$@
+
+
+    # store current flag state
+    flags=$-
+
+    # allow a failures to continue
+    set +e
+    ${command}
+    exit_code=$?
+
+    # restore "e" flag
+    if [[ ${flags} =~ e ]]
+    then set -e
+    else set +e
+    fi
+
+    if [[ $exit_code == 0 ]]
+    then
+        return 0
+    fi
+
+    # failure
+    if [[ ${attempts_left} > 0 ]]
+    then
+        echo "failure (${exit_code}), sleeping ${sleep_seconds}..."
+        sleep ${sleep_seconds}
+        new_attempts=$((${attempts_left} - 1))
+        new_sleep=$((${sleep_seconds} * 2))
+        retry_with_backoff ${new_attempts} ${new_sleep} ${command}
+    fi
+
+    return $exit_code
+}
+
+## Helper functionss
+function now() { date +"%Y-%m-%d %H:%M:%S" | tr -d '\n'; }
+function msg() { println "$*" >&2; }
+function println() { printf '%s\n' "$(now) $*"; }

.kokoro/continuous/common.cfg

@@ -0,0 +1,25 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+    regex: "**/*sponge_log.txt"
+  }
+}
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "java-logging-servlet-initializer/.kokoro/trampoline.sh"
+
+env_vars: {
+  key: "TRAMPOLINE_BUILD_FILE"
+  value: "github/java-logging-servlet-initializer/.kokoro/build.sh"
+}
+
+env_vars: {
+  key: "JOB_TYPE"
+  value: "test"
+}

.kokoro/continuous/java8.cfg

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+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+  key: "TRAMPOLINE_IMAGE"
+  value: "gcr.io/cloud-devrel-kokoro-resources/java8"
+}
+
+env_vars: {
+  key: "REPORT_COVERAGE"
+  value: "true"
+}

.kokoro/continuous/propose_release.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eo pipefail
+
+export NPM_CONFIG_PREFIX=/home/node/.npm-global
+
+if [ -f ${KOKORO_KEYSTORE_DIR}/73713_github-magic-proxy-url-release-please ]; then
+  # Groom the release PR as new commits are merged.
+  npx release-please release-pr --token=${KOKORO_KEYSTORE_DIR}/73713_github-magic-proxy-token-release-please \
+    --repo-url=googleapis/java-logging-servlet-initializer \
+    --package-name="logging-logback" \
+    --api-url=${KOKORO_KEYSTORE_DIR}/73713_github-magic-proxy-url-release-please \
+    --proxy-key=${KOKORO_KEYSTORE_DIR}/73713_github-magic-proxy-key-release-please \
+    --release-type=java-yoshi
+fi