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Configuring Different Types of Hooks

In this guide, we are going to discuss how to configure different types of hooks. Here, we will give some examples of different configurations.

HTTPGet

httpGet hook allows sending an HTTP GET request to an HTTP server before and after the backup/restore process. The following configurable fields are available for httpGet hook.

Field Field Type Data Type Usage
host Optional String Specify the name of the host where the GET request will be sent. If you don’t specify this field, Stash will use the hook executor Pod IP as host.
port Required Integer or String Specify the port where the HTTP server is listening. You can specify a numeric port or the name of the port in case of the HTTP server is running in the same pod where the hook will be executed. If you specify the port name, you must specify the containerName field of the hook.
path Required String Specify the path to access on the HTTP server.
scheme Required String Specify the scheme to use to connect with the host.
httpHeaders Optional Array of Objects Specify a list of custom headers to set in the request.

Examples:

  • Hook with host and port are specified:
preBackup:
  httpGet:
    host: my-host.demo.svc
    port: 8080
    path: "/"
    scheme: HTTP
  • Hook to extract host and port from the hook executor pod:
preBackup:
  httpGet:
    port: my-port
    path: "/"
    scheme: HTTP
  containerName: my-container
  • Hook for sending custom header in the HTTP request:
preBackup:
  httpGet:
    host: my-host.demo.svc
    port: 8080
    path: "/"
    scheme: HTTP
    httpHeaders:
    - name: "User-Agent"
      value: "stash/0.9.x"

HTTPPost

httpPost hook allows sending an HTTP POST request to an HTTP server before and after the backup/restore process. The following configurable fields are available for httpPost hook.

Field Field Type Data Type Usage
host Optional String Specify the name of the host where the POST request will be sent. If you don’t specify this field, Stash will use the hook executor Pod IP as host.
port Required Integer or String Specify the port where the HTTP server is listening. You can specify a numeric port or the name of the port if your HTTP server is running in the same pod where the hook will be executed. If you specify the port name, you must specify the containerName field of the hook.
path Required String Specify the path to access on the HTTP server.
scheme Required String Specify the scheme to use to connect with the host.
httpHeaders Optional Array of Objects Specify a list of custom headers to set in the request.
body Optional String Specify the data to send in the request body.
form Optional Array of Objects Specify the data to send as URL encoded form with the request.

Examples:

  • Send JSON data in the request body:
preBackup:
  httpPost:
    host: my-service.mynamespace.svc
    path: /demo
    port: 8080
    scheme: HTTP
    httpHeaders:
    - name: Content-Type
      value: application/json
    body: '{
            "name": "john doe",
            "age": "28"
           }'
  • Send URL encoded form in the request:
preBackup:
  httpPost:
    host: my-service.mynamespace.svc
    path: /demo
    port: 8080
    scheme: HTTP
    form:
    - key: "name"
      values: ["john doe"]
    - key: "age"
      values: ["28"]

TCPSocket

tcpSocket hook allows running a check against a TCP port to verify whether it is open or not. The following configurable fields are available for tcpSocket hook.

Field Field Type Data Type Usage
host Optional String Specify the name of the host where the server is running. If you don’t specify this field, Stash will use the hook executor Pod IP as host.
port Required Integer or String Specify the port to check. You can specify a numeric port or the name of the port when your server is running in the same pod where the hook will be executed. If you specify the port name, you must specify the containerName field of the hook.

Examples:

  • Hook with host and port field specified.
preBackup:
  tcpSocket:
    host: my-host.demo.svc
    port: 8080
  • Hook to extract host and port from the hook executor pod.
preBackup:
  tcpSocket:
    port: my-port
  containerName: my-container

Exec

exec hook allows running commands inside a container before or after the backup/restore process. The following configurable fields are available for exec hook.

Field Field Type Data Type Usage
command Required Array of Strings Specify a list of commands to execute.

If you don’t specify containerName for exec hook, the command will be executed into the 0th container of the respective pod.

Examples:

  • Hook to remove old corrupted data before restore:
preRestore:
  exec:
    command: ["/bin/sh","-c","rm -rf /corrupted/data/directory"]
  containerName: my-container
  • Hook to make a MySQL database read-only before backup:
preBackup:
  exec:
    command:
      - /bin/sh
      - -c
      - mysql -u root --password=$MYSQL_ROOT_PASSWORD -e "SET GLOBAL super_read_only = ON;"
  containerName: mysql
  • Hook to make a MySQL database writable after backup:
postBackup:
  exec:
    command:
      - /bin/sh
      - -c
      - mysql -u root --password=$MYSQL_ROOT_PASSWORD -e "SET GLOBAL super_read_only = OFF;"
  containerName: mysql
  • Hook to remove corrupted MySQL database before restoring:
preRestore:
  exec:
    command:
      - /bin/sh
      - -c
      - mysql -u root --password=$MYSQL_ROOT_PASSWORD -e "DROP DATABASE companyRecord;"
  containerName: mysql
  • Hook to apply some migration after restoring a MySQL database:
postRestore:
  exec:
    command:
      - /bin/sh
      - -c
      - mysql -u root --password=$MYSQL_ROOT_PASSWORD -e "RENAME TABLE companyRecord.employee TO companyRecord.salaryRecord;"
  containerName: mysql

If the above hooks do not cover your use cases or you have any questions regarding the hooks, please feel free to open an issue here.