asteris-llc/converge

// Copyright © 2016 Asteris, LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package wait

import (
    "fmt"
    "time"

    "github.com/asteris-llc/converge/load/registry"
    "github.com/asteris-llc/converge/resource"
    "github.com/asteris-llc/converge/resource/shell"
    "golang.org/x/net/context"
)

// Preparer handles wait.query tasks
type Preparer struct {
    // the shell interpreter that will be used for your scripts. `/bin/sh` is
    // used by default.
    Interpreter string `hcl:"interpreter"`

    // the script to run to check if a resource is ready. exit with exit code 0 if
    // the resource is healthy, and 1 (or above) otherwise.
    Check string `hcl:"check" required:"true" nonempty:"true"`

    // flags to pass to the `interpreter` binary to check validity. For
    // `/bin/sh` this is `-n`.
    CheckFlags []string `hcl:"check_flags"`

    // flags to pass to the interpreter at execution time.
    ExecFlags []string `hcl:"exec_flags"`

    // the amount of time the command will wait before halting forcefully.
    Timeout *time.Duration `hcl:"timeout"`

    // the working directory this command should be run in.
    Dir string `hcl:"dir"`

    // any environment variables that should be passed to the command.
    Env map[string]string `hcl:"env"`

    // the amount of time to wait in between checks. If the interval is not
    // specified, it will default to 5 seconds.
    Interval *time.Duration `hcl:"interval"`

    // the amount of time to wait before running the first check and after a
    // successful check. If no grace period is specified, no grace period will be
    // taken into account.
    GracePeriod *time.Duration `hcl:"grace_period"`

    // the maximum number of attempts before the wait fails. If the maximum number
    // of retries is not set, it will default to 5.
    MaxRetry *int `hcl:"max_retry"`
}

// Prepare creates a new wait type
func (p *Preparer) Prepare(ctx context.Context, render resource.Renderer) (resource.Task, error) {
    shPrep := &shell.Preparer{
        Interpreter: p.Interpreter,
        Check:       p.Check,
        CheckFlags:  p.CheckFlags,
        ExecFlags:   p.ExecFlags,
        Timeout:     p.Timeout,
        Dir:         p.Dir,
        Env:         p.Env,
    }

    task, err := shPrep.Prepare(ctx, render)

    if err != nil {
        return &Wait{}, err
    }

    shell, ok := task.(*shell.Shell)
    if !ok {
        return &Wait{}, fmt.Errorf("expected *shell.Shell but got %T", task)
    }

    wait := &Wait{
        Shell:   shell,
        Retrier: PrepareRetrier(p.Interval, p.GracePeriod, p.MaxRetry),
    }

    return wait, nil
}

func init() {
    registry.Register("wait.query", (*Preparer)(nil), (*Wait)(nil))
}