Run Shellcheck on instance reload command

Shellcheck was being run on the reload command for pgBackRest. During
the auto-grow work, we noticed that the reload command for the instance
was not being checked. Since we had to update the auto-grow bash logic to
pass Shellcheck for pgBackRest, it seemed appropriate to enable the checks for the
instance as well.

Author: sfc-gh-jmckulka

internal/postgres/config.go

@@ -298,13 +298,24 @@ func reloadCommand(
 	// descriptor gets closed and reopened to use the builtin `[ -nt` to check
 	// mtimes.
 	// - https://unix.stackexchange.com/a/407383
+	//
+	// In the manageAutogrowAnnotation function below, df is used to return the
+	// relevant volume size in Mebibytes. The 'read' variable gets the value from
+	// the '1M-blocks' output (second column) and the 'use' variable gets the value
+	// from the 'Use%' column (fifth column). This value is grabbed after stripping
+	// out the column headers (before the '\n') and then getting the respective
+	// value delimited by the white spaces by using the 'read -r' command.
+	// The underscores (_) discard fields and the variables store them. This allows
+	// for selective parsing of the provided lines. The percent value is stripped of
+	// the '%' and then used to determine if a expansion should be triggered by
+	// setting the calculated volume size using the 'size' variable.
 	script := fmt.Sprintf(`
 # Parameters for curl when managing autogrow annotation.
 APISERVER="https://kubernetes.default.svc"
 SERVICEACCOUNT="/var/run/secrets/kubernetes.io/serviceaccount"
-NAMESPACE=$(cat ${SERVICEACCOUNT}/namespace)
-TOKEN=$(cat ${SERVICEACCOUNT}/token)
-CACERT=${SERVICEACCOUNT}/ca.crt
+NAMESPACE=$(cat "${SERVICEACCOUNT}/namespace")
+TOKEN=$(cat "${SERVICEACCOUNT}/token")
+CACERT="${SERVICEACCOUNT}/ca.crt"
 
 # Manage autogrow annotation.
 # Return size in Mebibytes.
@@ -313,27 +324,29 @@ manageAutogrowAnnotation() {
   local trigger=$2
   local maxGrow=$3
 
-  size=$(df --block-size=M /"${volume}" | awk 'FNR == 2 {print $2}')
-  use=$(df /"${volume}" | awk 'FNR == 2 {print $5}')
+  size=$(df --block-size=M /"${volume}")
+  read -r _ size _ <<< "${size#*$'\n'}"
+  use=$(df /"${volume}")
+  read -r _ _ _ _ use _ <<< "${use#*$'\n'}"
   sizeInt="${size//M/}"
   # Use the sed punctuation class, because the shell will not accept the percent sign in an expansion.
-  useInt=$(echo $use | sed 's/[[:punct:]]//g')
+  useInt=${use//[[:punct:]]/}
   triggerExpansion="$((useInt > trigger))"
-  if [[ $triggerExpansion -eq 1 ]]; then
+  if [[ ${triggerExpansion} -eq 1 ]]; then
     newSize="$(((sizeInt / 2)+sizeInt))"
     # Only compare with maxGrow if it is set (not empty)
-    if [[ -n "$maxGrow" ]]; then
+    if [[ -n "${maxGrow}" ]]; then
         # check to see how much we would normally grow
         sizeDiff=$((newSize - sizeInt))
 
         # Compare the size difference to the maxGrow; if it is greater, cap it to maxGrow
-        if [[ $sizeDiff -gt $maxGrow ]]; then
+        if [[ ${sizeDiff} -gt ${maxGrow} ]]; then
             newSize=$((sizeInt + maxGrow))
         fi
     fi
     newSizeMi="${newSize}Mi"
-    d='[{"op": "add", "path": "/metadata/annotations/suggested-'"${volume}"'-pvc-size", "value": "'"$newSizeMi"'"}]'
-    curl --cacert ${CACERT} --header "Authorization: Bearer ${TOKEN}" -XPATCH "${APISERVER}/api/v1/namespaces/${NAMESPACE}/pods/${HOSTNAME}?fieldManager=kubectl-annotate" -H "Content-Type: application/json-patch+json" --data "$d"
+    d='[{"op": "add", "path": "/metadata/annotations/suggested-'"${volume}"'-pvc-size", "value": "'"${newSizeMi}"'"}]'
+    curl --cacert "${CACERT}" --header "Authorization: Bearer ${TOKEN}" -XPATCH "${APISERVER}/api/v1/namespaces/${NAMESPACE}/pods/${HOSTNAME}?fieldManager=kubectl-annotate" -H "Content-Type: application/json-patch+json" --data "${d}"
   fi
 }
 

internal/postgres/config_test.go

@@ -18,9 +18,11 @@ import (
 	"time"
 
 	"gotest.tools/v3/assert"
+	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"sigs.k8s.io/yaml"
 
+	"github.com/crunchydata/postgres-operator/internal/initialize"
 	"github.com/crunchydata/postgres-operator/internal/testing/cmp"
 	"github.com/crunchydata/postgres-operator/internal/testing/require"
 	"github.com/crunchydata/postgres-operator/pkg/apis/postgres-operator.crunchydata.com/v1beta1"
@@ -600,3 +602,44 @@ EOF
 chmod +x /tmp/pg_rewind_tde.sh`))
 	})
 }
+
+func TestReloadCommand(t *testing.T) {
+	shellcheck := require.ShellCheck(t)
+
+	pgdataSize := resource.MustParse("1Gi")
+	pgwalSize := resource.MustParse("2Gi")
+
+	command := reloadCommand(
+		"some-name",
+		&v1beta1.VolumeClaimSpecWithAutoGrow{
+			AutoGrow: &v1beta1.AutoGrowSpec{
+				Trigger: initialize.Int32(10),
+				MaxGrow: &pgdataSize,
+			},
+		},
+		&v1beta1.VolumeClaimSpecWithAutoGrow{
+			AutoGrow: &v1beta1.AutoGrowSpec{
+				Trigger: initialize.Int32(20),
+				MaxGrow: &pgwalSize,
+			},
+		},
+	)
+
+	// Expect a bash command with an inline script.
+	assert.DeepEqual(t, command[:3], []string{"bash", "-ceu", "--"})
+	assert.Assert(t, len(command) > 3)
+
+	// Write out that inline script.
+	dir := t.TempDir()
+	file := filepath.Join(dir, "script.bash")
+	assert.NilError(t, os.WriteFile(file, []byte(command[3]), 0o600))
+
+	// Expect shellcheck to be happy.
+	cmd := exec.CommandContext(t.Context(), shellcheck, "--enable=all", file)
+	output, err := cmd.CombinedOutput()
+	assert.NilError(t, err, "%q\n%s", cmd.Args, output)
+
+	assert.Assert(t, cmp.Contains(command[3], "manageAutogrowAnnotation \"pgdata\" \"10\" \"1024\""))
+	assert.Assert(t, cmp.Contains(command[3], "manageAutogrowAnnotation \"pgwal\" \"20\" \"2048\""))
+
+}

internal/postgres/reconcile_test.go

@@ -173,9 +173,9 @@ containers:
     # Parameters for curl when managing autogrow annotation.
     APISERVER="https://kubernetes.default.svc"
     SERVICEACCOUNT="/var/run/secrets/kubernetes.io/serviceaccount"
-    NAMESPACE=$(cat ${SERVICEACCOUNT}/namespace)
-    TOKEN=$(cat ${SERVICEACCOUNT}/token)
-    CACERT=${SERVICEACCOUNT}/ca.crt
+    NAMESPACE=$(cat "${SERVICEACCOUNT}/namespace")
+    TOKEN=$(cat "${SERVICEACCOUNT}/token")
+    CACERT="${SERVICEACCOUNT}/ca.crt"
 
     # Manage autogrow annotation.
     # Return size in Mebibytes.
@@ -184,27 +184,29 @@ containers:
       local trigger=$2
       local maxGrow=$3
 
-      size=$(df --block-size=M /"${volume}" | awk 'FNR == 2 {print $2}')
-      use=$(df /"${volume}" | awk 'FNR == 2 {print $5}')
+      size=$(df --block-size=M /"${volume}")
+      read -r _ size _ <<< "${size#*$'\n'}"
+      use=$(df /"${volume}")
+      read -r _ _ _ _ use _ <<< "${use#*$'\n'}"
       sizeInt="${size//M/}"
       # Use the sed punctuation class, because the shell will not accept the percent sign in an expansion.
-      useInt=$(echo $use | sed 's/[[:punct:]]//g')
+      useInt=${use//[[:punct:]]/}
       triggerExpansion="$((useInt > trigger))"
-      if [[ $triggerExpansion -eq 1 ]]; then
+      if [[ ${triggerExpansion} -eq 1 ]]; then
         newSize="$(((sizeInt / 2)+sizeInt))"
         # Only compare with maxGrow if it is set (not empty)
-        if [[ -n "$maxGrow" ]]; then
+        if [[ -n "${maxGrow}" ]]; then
             # check to see how much we would normally grow
             sizeDiff=$((newSize - sizeInt))
 
             # Compare the size difference to the maxGrow; if it is greater, cap it to maxGrow
-            if [[ $sizeDiff -gt $maxGrow ]]; then
+            if [[ ${sizeDiff} -gt ${maxGrow} ]]; then
                 newSize=$((sizeInt + maxGrow))
             fi
         fi
         newSizeMi="${newSize}Mi"
-        d='[{"op": "add", "path": "/metadata/annotations/suggested-'"${volume}"'-pvc-size", "value": "'"$newSizeMi"'"}]'
-        curl --cacert ${CACERT} --header "Authorization: Bearer ${TOKEN}" -XPATCH "${APISERVER}/api/v1/namespaces/${NAMESPACE}/pods/${HOSTNAME}?fieldManager=kubectl-annotate" -H "Content-Type: application/json-patch+json" --data "$d"
+        d='[{"op": "add", "path": "/metadata/annotations/suggested-'"${volume}"'-pvc-size", "value": "'"${newSizeMi}"'"}]'
+        curl --cacert "${CACERT}" --header "Authorization: Bearer ${TOKEN}" -XPATCH "${APISERVER}/api/v1/namespaces/${NAMESPACE}/pods/${HOSTNAME}?fieldManager=kubectl-annotate" -H "Content-Type: application/json-patch+json" --data "${d}"
       fi
     }