Created
November 27, 2022 20:05
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Collect multiple K8S resources into YAML files based on a grep expression
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| #!/bin/bash | |
| set -e | |
| set -u | |
| set -o pipefail | |
| ######################################## DESCRIPTION ############################################################# | |
| ## Use this script to collect multiple resources into YAML files. ## | |
| ## ## | |
| ## The mandatory '--exp' option takes a grep expression to match against all 'kind.group'. ## | |
| ## ## | |
| ## i.e. 'collect_k8s_resources_by_expression.sh --exp monitoring.coreos.com' ## | |
| ## will result in a 'collected' directory with a bunch of YAML files for every CR in monitoring.coreos.com. ## | |
| ## doing '--exp coreos.com' might include a broader wide of YAML files as we grep over `kubectl api-resources`. ## | |
| ## the more specific the expression, the last YAML files we'll get, and the less time this script takes to run. ## | |
| ## ## | |
| ## OVERUSAGE WARNING: will result in a lot of API requests and a lengthy runtime, ## | |
| ## think about your expression b4 running it! ## | |
| ################################################################################################################## | |
| ####################################### USAGE EXAMPLES ############################################ | |
| ## bash ./collect_k8s_resources_by_expression.sh --exp coreos.com ## | |
| ## bash ./collect_k8s_resources_by_expression.sh --exp coreos.com --dir collected ## | |
| ## bash ./collect_k8s_resources_by_expression.sh --exp coreos.com --dir collected --nonamespaced ## | |
| ## bash ./collect_k8s_resources_by_expression.sh --exp coreos.com --dir collected --noclustered ## | |
| ## bash ./collect_k8s_resources_by_expression.sh --exp coreos.com --clean ## | |
| ################################################################################################### | |
| # iterate over arguments and create named parameters | |
| while [ $# -gt 0 ]; do | |
| if [[ $1 == *"--"* ]]; then | |
| param="${1/--/}" | |
| if [ -z ${2+x} ] || [[ $2 = --* ]]; then | |
| declare $param="true" | |
| else | |
| declare $param="$2" | |
| fi | |
| fi | |
| shift | |
| done | |
| # set non-required parameters defaults | |
| dir=${dir:-collected} | |
| nonamespaced=${nonamespaced:-false} | |
| noclustered=${noclustered:-false} | |
| clean=${clean:-false} | |
| # verify required parameters | |
| if [ -z ${exp+x} ]; then | |
| echo "ERROR: You must specify a grep expression using the '--exp' option. i.e. a partial resource group." | |
| exit 1 | |
| fi | |
| if [ $nonamespaced = "true" ] && [ $noclustered = "true" ] ; then | |
| echo "ERROR: The '--nonamespaced' skips namespace resources, the '--noclustered' skips cluster ones, these cannot be combined." | |
| exit 1 | |
| fi | |
| # get kind from 'kind.group' | |
| get_kind() { | |
| IFS='.' kgsplit=($1) | |
| echo ${kgsplit[0]} | |
| } | |
| # get name from kind.group/name | |
| get_name_cluster() { | |
| IFS='/' kgsplit=($1) | |
| echo ${kgsplit[1]} | |
| } | |
| # gather 'kubectl get' commands | |
| commands=() | |
| # use the --nonamespaced option to disable namespace resources fetch | |
| if [ $nonamespaced != "true" ]; then | |
| # grab namespaced api resources | |
| namepsaced=`kubectl api-resources --no-headers --namespaced=true -o name | grep $exp` | |
| if [ -z "$namepsaced" ]; then | |
| echo "WARN: no namespaced resources matching regex expression '$exp' found" | |
| else | |
| records=($namepsaced) | |
| for rec in "${records[@]}"; do | |
| crs=`kubectl get $rec -A -o 'custom-columns=ns:.metadata.namespace,n:.metadata.name' --no-headers` | |
| if [ ! -z "$crs" ]; then | |
| kind=$(get_kind $rec) | |
| IFS=$'\n' resources=($crs) | |
| for res in "${resources[@]}"; do | |
| sanitized=`echo $res | xargs` | |
| target="$dir"/"$kind"_"${sanitized// /_}.yaml" | |
| commands+=("kubectl get $rec -n $sanitized -o yaml > $target") | |
| done | |
| fi | |
| done | |
| fi | |
| fi | |
| # use the --noclustered option to disable cluster resources fetch | |
| if [ $noclustered != "true" ]; then | |
| # grab clustrer api resources | |
| clustered=`kubectl api-resources --namespaced=false -o name | grep $exp` | |
| if [ -z "$clustered" ]; then | |
| echo "WARN: no clustered resources matching regex expression '$exp' found" | |
| else | |
| records=($clustered) | |
| for rec in "${records[@]}"; do | |
| crs=`kubectl get $rec -o name --no-headers` | |
| if [ ! -z "$crs" ]; then | |
| kind=$(get_kind $rec) | |
| IFS=$'\n' resources=($crs) | |
| for res in "${resources[@]}"; do | |
| name=$(get_name_cluster $res) | |
| target="$dir"/"$kind"_"cluster_$name.yaml" | |
| commands+=("kubectl get $rec $name -o yaml > $target") | |
| done | |
| fi | |
| done | |
| fi | |
| fi | |
| # clean target directory | |
| if [ $clean = "true" ]; then | |
| rm -rf $dir | |
| fi | |
| # create target directory if doesn't exists | |
| if [ ! -d "$dir" ]; then | |
| mkdir -p $dir | |
| fi | |
| # remove (if) existing commands file | |
| rm -f $dir/commands | |
| # list and evaluate all commands - will result in a list-file and 0-to-many CR yaml files | |
| for cmd in "${commands[@]}"; do | |
| echo $cmd >> $dir/commands | |
| eval $cmd | |
| done |
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