How to rewrite grep in #!/bin/sh? - shell

Question

I have the following shell script, that does not compile:
#!/bin/sh
.....
.....
clean_up() {
echo "Clean up"
docker stop $KC_TEST_SVC
docker stop $KC_NAME
docker stop $POSTGRES_NAME
docker network rm $KC_NETWORK
}
# Check network if exists, if not then create
docker network inspect $KC_NETWORK
if [ $? -eq 1 ]; then
docker network create $KC_NETWORK
if [ $? -eq 1 ]; then
exit 1
fi
fi
docker run -d --rm --name $POSTGRES_NAME \
-e POSTGRES_DB=$POSTGRES_DB \
-e POSTGRES_USER=$POSTGRES_USER \
-e POSTGRES_PASSWORD=$POSTGRES_PW \
--network=$KC_NETWORK \
postgres:12.3
if [ $? -eq 1 ]; then
exit 1
fi
docker build --build-arg STAGE=int --tag $KC_TAG .
if [ $? -eq 1 ]; then
exit 1
fi
docker run -d --rm --name $KC_NAME \
-e DB_VENDOR=POSTGRES \
-e DB_ADDR=$POSTGRES_NAME \
-e DB_DATABASE=$POSTGRES_DB \
-e DB_USER=$POSTGRES_USER \
-e DB_PASSWORD=$POSTGRES_PW \
-e KEYCLOAK_USER=$KC_USER \
-e KEYCLOAK_PASSWORD=$KC_PW \
-e KEYCLOAK_LOGLEVEL=DEBUG \
--network=$KC_NETWORK \
$KC_TAG "-Dkeycloak.migration.action=import -Dkeycloak.migration.provider=dir -Dkeycloak.migration.dir=/opt/jboss/keycloak/import-dir -Dkeycloak.migration.strategy=OVERWRITE_EXISTING"
if [ $? -eq 1 ]; then
exit 1
fi
# Wait until Keycloak get started
sleep 30
# Run test jetty service that is protected with Keycloak
docker run -d --rm --name $KC_TEST_SVC \
-v $(pwd)/app:/app \
--network $KC_NETWORK \
hub.databaker.io/devops/jetty-keycloak:0.1.6
if [ $? -eq 1 ]; then
exit 1
fi
# Request Tokens for credentials
KC_URL=http://$KC_SERVER/$KC_CONTEXT/realms/$KC_REALM/protocol/openid-connect/token
echo "Keycloak URL => $KC_URL"
echo "Test the client connection to Keycloak with user $KC_TEST_USER"
KC_RESPONSE=$(
docker run --rm --network=$KC_NETWORK curlimages/curl:7.71.1 -X POST \
-d "username=$KC_TEST_USER" \
-d "password=$KC_TEST_PW" \
-d "grant_type=password" \
-d "client_id=$KC_TEST_CLIENT" \
$KC_URL | docker run --rm -i stedolan/jq .
)
echo "Response from Keycloak $KC_RESPONSE"
if grep -q "error" <<< "$KC_RESPONSE"; then
echo "++++++++Error+++++++++"
exit 1
fi
KC_ACCESS_TOKEN=$(echo "$KC_RESPONSE" | docker run --rm -i stedolan/jq -r .access_token)
echo "Access token from KC => $KC_ACCESS_TOKEN"
echo "Make request to protected service"
SVC_URL=http://$KC_TEST_SVC:8080/api/health
SVC_RES=$(docker run --rm --network=$KC_NETWORK curlimages/curl:7.71.1 -v -k \
-H "Authorization: Bearer $KC_ACCESS_TOKEN" \
-H "Accept: application/json" \
$SVC_URL | docker run --rm -i stedolan/jq .status)
clean_up
echo "$SVC_RES"
if [ "$SVC_RES" != "I am healthy" ]; then
echo "Test failed."
exit 1
else
echo "Test was successful. The service response $SVC_RES."
fi
it complains:
Syntax error: redirection unexpected
due to of the following line:
if grep -q "error" <<< "$KC_RESPONSE"; then
echo "++++++++Error+++++++++"
exit 1
fi
#!/bin/sh does not support grep. How to rewrite it?

Answer 1

<<< is a here string and it's a bash extension. In posix shell, just pipe the data.
if printf "%s\n" "$KC_RESPONSE" | grep -q "error"; then
Do not do if [ $? -eq 1 ]; then, it's error prone. Do if ! command; then. (You might want to research set -eu).

Answer 2

Change #!/bin/sh to #!/bin/bash (ev. replace bash location, which bash helps to find location of bash, and to see if bash is installed), or you may need to rewrite your script in a portable way. In this case, create a temporary file, put the string in such file, redirect such file to grep (with single <), and then delete the temporary file.
With such long description, you see why there is an extension in bash, on the other hand, it is nearly a syntactic sugar: you can easily do the same.