Command Hooks

Run commands before, after success or after failure

resticprofile has 2 places where you can run commands around restic:

  • commands that will run before and after every restic command (snapshots, backup, check, forget, prune, mount, etc.). These are placed at the root of each profile and are always considered.
  • commands that will only run before and after specific restic commands. These are placed in supported sections of your profiles (currently supported are backup, copy, dump, find, ls, mount, restore, snapshots, stats and tag).

Here’s an example of all the external commands that you can run during the execution of a profile:

​
version = "1"

[documents]
  run-before = 'echo "== run-before profile $PROFILE_NAME and command $PROFILE_COMMAND"'
  run-after = 'echo "== run-after profile $PROFILE_NAME and command $PROFILE_COMMAND"'
  run-after-fail = 'echo "== ERROR in profile $PROFILE_NAME command ${PROFILE_COMMAND}: $ERROR_MESSAGE"'
  run-finally = 'echo "== run-finally from profile $PROFILE_NAME after command $PROFILE_COMMAND"'

  [documents.backup]
    run-before = 'echo "=== run-before backup in profile $PROFILE_NAME"'
    run-after = 'echo "=== run-after backup in profile $PROFILE_NAME"'
    run-after-fail = 'echo "=== ERROR in backup for profile ${PROFILE_NAME}: $ERROR_MESSAGE"'
    run-finally = 'echo "=== run-finally after backup in profile $PROFILE_NAME"'
    source = "~/Documents"
version: "1"

documents:
  run-before: 'echo "== run-before profile $PROFILE_NAME and command $PROFILE_COMMAND"'
  run-after: 'echo "== run-after profile $PROFILE_NAME and command $PROFILE_COMMAND"'
  run-after-fail: 'echo "== ERROR in profile $PROFILE_NAME command ${PROFILE_COMMAND}: $ERROR_MESSAGE"'
  run-finally: 'echo "== run-finally from profile $PROFILE_NAME after command $PROFILE_COMMAND"'

  backup:
    run-before: 'echo "=== run-before backup in profile $PROFILE_NAME"'
    run-after: 'echo "=== run-after backup in profile $PROFILE_NAME"'
    run-after-fail: 'echo "=== ERROR in backup for profile ${PROFILE_NAME}: $ERROR_MESSAGE"'
    run-finally: 'echo "=== run-finally after backup in profile $PROFILE_NAME"'
    source: ~/Documents
documents {
    run-before = "echo \"== run-before profile $PROFILE_NAME and command $PROFILE_COMMAND\""
    run-after = "echo \"== run-after profile $PROFILE_NAME and command $PROFILE_COMMAND\""
    run-after-fail = "echo \"== ERROR in profile $PROFILE_NAME command ${PROFILE_COMMAND}: $ERROR_MESSAGE\""
    run-finally = "echo \"== run-finally from profile $PROFILE_NAME after command $PROFILE_COMMAND\""

    backup = {
        run-before = "echo \"=== run-before backup in profile $PROFILE_NAME\""
        run-after = "echo \"=== run-after backup in profile $PROFILE_NAME\""
        run-after-fail = "echo \"=== ERROR in backup for profile ${PROFILE_NAME}: $ERROR_MESSAGE\""
        run-finally = "echo \"=== run-finally after backup in profile $PROFILE_NAME\""
        source = "~/Documents"
    }
}
{
  "version": "1",
  "documents": {
    "run-before": "echo \"== run-before profile $PROFILE_NAME and command $PROFILE_COMMAND\"",
    "run-after": "echo \"== run-after profile $PROFILE_NAME and command $PROFILE_COMMAND\"",
    "run-after-fail": "echo \"== ERROR in profile $PROFILE_NAME command ${PROFILE_COMMAND}: $ERROR_MESSAGE\"",
    "run-finally": "echo \"== run-finally from profile $PROFILE_NAME after command $PROFILE_COMMAND\"",
    "backup": {
      "run-before": "echo \"=== run-before backup in profile $PROFILE_NAME\"",
      "run-after": "echo \"=== run-after backup in profile $PROFILE_NAME\"",
      "run-after-fail": "echo \"=== ERROR in backup for profile ${PROFILE_NAME}: $ERROR_MESSAGE\"",
      "run-finally": "echo \"=== run-finally after backup in profile $PROFILE_NAME\"",
      "source": "~/Documents"
    }
  }
}

run-before, run-after, run-after-fail and run-finally can be a string, or an array of strings if you need to run more than one command

A few environment variables will be set before running these commands:

  • PROFILE_NAME
  • PROFILE_COMMAND: backup, check, forget, etc.

Additionally, for the run-after-fail commands, these environment variables will also be available:

  • ERROR_MESSAGE (and ERROR) containing the latest error message
  • ERROR_COMMANDLINE containing the command line that failed
  • ERROR_EXIT_CODE containing the exit code of the command line that failed
  • ERROR_STDERR containing any message that the failed command sent to the standard error (stderr)

The commands of run-finally get the environment of run-after-fail when run-before, run-after or restic failed.

Failures to run commands in run-finally are logged but do not influence environment, return code nor running of further commands listed in run-finally. This makes it the perfect choice for custom cleanup tasks that must always run.

All other command errors (= non-zero return code from a command) will skip running further commands in the same list and/or abort the flow.

Output when running the example from above

➜ resticprofile documents.backup
== run-before profile documents and command backup
=== run-before backup in profile documents
...
processed 355 files, 11.722 MiB in 0:00
snapshot 3949d2fb saved
...
=== run-after backup in profile documents
== run-after profile documents and command backup
=== run-finally after backup in profile documents
== run-finally from profile documents after command backup

Order of run-* during a backup

The commands will be running in this order during a backup:

  • run-before from the profile - if error, go to run-after-fail
  • run-before from the backup section - if error, go to run-after-fail from backup section
  • run the restic backup (with check and retention if configured) - if error, go to run-after-fail from backup section
  • run-after from the backup section - if error, go to run-after-fail from backup section
  • run-after from the profile - if error, go to run-after-fail
  • If error: run-after-fail from the backup section - if error, go to run-finally
  • If error: run-after-fail from the profile - if error, go to run-finally
  • run-finally from the backup section - if error, log and continue with next
  • run-finally from the profile - if error, log and continue with next

Maybe it’s easier to understand with a flow diagram:

flowchart TB
    LOCK(set resticprofile lock)
    UNLOCK(delete resticprofile lock)
    PRB('run-before' from profile)
    PRA('run-after' from profile)

    subgraph Backup [ ]
        BRB('run-before' from backup section)
        BRA('run-after' from backup section)
        RUN(run restic backup with check and/or retention if configured)
    end

    subgraph Failure [ ]
        BFAIL('run-after-fail' from backup section)
        PFAIL('run-after-fail' from profile)
    end

    subgraph Finally [ ]
        direction TB
        BRF('run-finally' from backup section)
        PRF('run-finally' from profile)
        BRF --> PRF
    end

    LOCK --> PRB
    PRB -->|Error| PFAIL
    PRB -->|Success| BRB

    BRB -->|Error| BFAIL
    BRB -->|Success| RUN

    RUN -->|Error| BFAIL
    RUN -->|Success| BRA

    BRA -->|Error| BFAIL
    BRA -->|Success| PRA

    BFAIL -->|Error| Finally
    BFAIL --> PFAIL

    PRA -->|Error| PFAIL
    PRA -->|Success| Finally
    PFAIL --> Finally
    Finally --> UNLOCK

    style Backup fill:#9990,stroke:#9990
    style Failure fill:#9990,stroke:#9990
    style Finally fill:#9991,stroke:#9994,stroke-width:4px
resticprofile lock

The local resticprofile lock is surrounding the whole process. It means that the run-after-fail target is not called if the lock cannot be obtained. This is a limitation of the current implementation.

Run commands on stream errors

In addition to hooks around profile and command execution, resticprofile allows to monitor the standard error stream of the current running command and trigger a custom hook when an output error line matches a regular expression pattern.

​
version = "1"

[default]

[[default.stream-error]]
pattern = ".+ERROR.+"
run = 'echo "Found ERROR at least 5 times in ${PROFILE_COMMAND}. Last matched line:"; cat - '
max-runs = 0
min-matches = 5
version: "1"

default:
  stream-error:
    - pattern: ".+ERROR.+"
      run: 'echo "Found ERROR at least 5 times in ${PROFILE_COMMAND}. Last matched line:"; cat - '
      max-runs: 0
      min-matches: 5
default {
  stream-error = {
      pattern = ".+ERROR.+" 
      run = "echo \"Found ERROR at least 5 times in ${PROFILE_COMMAND}. Last matched line:\"; cat - "
      max-runs = 0
      min-matches = 5
  }
}
{
  "version": "1",
  "default": {
    "stream-error": [
      {
        "pattern": ".+ERROR.+",
        "run": "echo \"Found ERROR at least 5 times in ${PROFILE_COMMAND}. Last matched line:\"; cat - ",
        "max-runs": 0,
        "min-matches": 5
      }
    ]
  }
}

The config structure stream-error can be defined multiple times within a profile and consists of the following properties:

  • pattern: a regular expression pattern matched against every line of stderr.
  • run: the command to run when pattern is found in stderr.
  • max-runs: maximum number of times that run is started for a single monitored command (or 0 for no limit).
  • min-matches: minimum number of times that pattern must match before starting run.

The run command inherits the environment of the monitored command on a pattern match, which always includes:

  • PROFILE_NAME
  • PROFILE_COMMAND: backup, check, forget, etc.

Stdin of the run command is populated with the error output line that matched the pattern. Using "cat -" in run effectively prints the line that triggered the action.

The following example shows how this could have been used with restic to address check failures caused by over usage of /tmp/ (restic fixed this problem in 0.14.0):

​
version = "1"

[default]

[[default.stream-error]]
pattern = "/tmp/restic-check-cache.+no space left on device"
run = "rm -Rf /tmp/restic-check-cache*"

[[default.stream-error]]
pattern = "mkdir /tmp/restic-check-cache.+no such file or directory"
run = "cat - | cut -d : -f 2 - | grep -E 'mkdir /tmp[^ \\.]+$' | sed 's/mkdir/mkdir -p/' - | sh"
version: "1"

default:
  stream-error:
    - pattern: "/tmp/restic-check-cache.+no space left on device"
      run: "rm -Rf /tmp/restic-check-cache*"
    - pattern: "mkdir /tmp/restic-check-cache.+no such file or directory"
      run: "cat - | cut -d : -f 2 - | grep -E 'mkdir /tmp[^ \\.]+$' | sed 's/mkdir/mkdir -p/' - | sh"