Commit graph

42 commits

Author SHA1 Message Date
Paul Stack f99b814f13
Ensure ResourceReference is included in printPropertyValue (#6962)
Fixes: #6934

With this snippet of code:

```
func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		// Create an AWS resource (S3 Bucket)
		vpc, err := ec2.NewVpc(ctx, "main", &ec2.VpcArgs{
			CidrBlock: pulumi.String("10.0.0.0/16"),
		})
		if err != nil {
			return err
		}

		rt, err := ec2.NewRouteTable(ctx, "example", &ec2.RouteTableArgs{
			VpcId: vpc.ID(),
		})

		// Export the name of the bucket
		ctx.Export("rt", rt)
		return nil
	})
}
```

the CLI would panic on the diff as follows:

```
panic: fatal: An assertion has failed

goroutine 249 [running]:
github.com/pulumi/pulumi/sdk/v3/go/common/util/contract.failfast(...)
	/private/tmp/pulumi-20210422-70582-1bpvlru/sdk/go/common/util/contract/failfast.go:23
github.com/pulumi/pulumi/sdk/v3/go/common/util/contract.Assert(...)
	/private/tmp/pulumi-20210422-70582-1bpvlru/sdk/go/common/util/contract/assert.go:26
github.com/pulumi/pulumi/pkg/v3/engine.printPropertyValue(0xc0005d41b0, 0x57cce00, 0xc001da9050, 0x0, 0x1, 0x5932853, 0x4, 0x0)
	/private/tmp/pulumi-20210422-70582-1bpvlru/pkg/engine/diff.go:511 +0x1485
```

This was due to the entire object being added to the output and
the property being a ResourceReference

On the changing of the code to use a switch statement, we can
now include the ResourceReference and ensure that we catch any
missing case statements with a panic as default

This means the same piece of code now outputs to the CLI as
follows:

```
Outputs:
    rt: {
        URN: "urn:pulumi:dev::testing-new-engine-diff::aws:ec2/routeTable:RouteTable::example"
        ID : "rtb-09b37608ec34f3b49"
        PackageVersion: ""
    }

Resources:
    3 unchanged

Duration: 2s
```
2021-05-04 19:34:28 +01:00
pulumi-bot 73a66f48ea [breaking] Changing the version of go.mod in sdk / pkg to be v3 2021-04-14 19:32:18 +01:00
Pat Gavlin 418e2291a2
Protect against engine event mutation. (#5003)
Certain operations in `engine/diff` mutate engine events during display.
This mutation can occur concurrently with the serialization of the event
for persistence, which causes a panic in the CLI. These changes fix the
offending code and add code that copies each engine event before
persisteing it in order to guard against future issues.
2020-07-16 23:52:31 -07:00
Paul Stack 0824fc9a8b
Revert "Narrow a few interfaces." (#4987) 2020-07-09 15:19:12 +01:00
Pat Gavlin 45d2fa95d6
Narrow a few interfaces. (#4934)
- Remove `Info` from `Source`. This method was not used.
- Remove `Stack` from `EvalSource`. This method was not used.
- Remove `Type` and `URN` from `Step`. These values are available via
  `Res().URN.Type()` and `Res().URN`, respectively. This removes the
  possibility of inconsistencies between the type, URN, and state of the
  resource associated with a `Step`.
- Remove URN from StepEventMetadata.
2020-07-01 15:32:50 -07:00
CyrusNajmabadi 66bd3f4aa8
Breaking changes due to Feature 2.0 work
* Make `async:true` the default for `invoke` calls (#3750)

* Switch away from native grpc impl. (#3728)

* Remove usage of the 'deasync' library from @pulumi/pulumi. (#3752)

* Only retry as long as we get unavailable back.  Anything else continues. (#3769)

* Handle all errors for now. (#3781)


* Do not assume --yes was present when using pulumi in non-interactive mode (#3793)

* Upgrade all paths for sdk and pkg to v2

* Backport C# invoke classes and other recent gen changes (#4288)

Adjust C# generation

* Replace IDeployment with a sealed class (#4318)

Replace IDeployment with a sealed class

* .NET: default to args subtype rather than Args.Empty (#4320)

* Adding system namespace for Dotnet code gen

This is required for using Obsolute attributes for deprecations

```
Iam/InstanceProfile.cs(142,10): error CS0246: The type or namespace name 'ObsoleteAttribute' could not be found (are you missing a using directive or an assembly reference?) [/Users/stack72/code/go/src/github.com/pulumi/pulumi-aws/sdk/dotnet/Pulumi.Aws.csproj]
Iam/InstanceProfile.cs(142,10): error CS0246: The type or namespace name 'Obsolete' could not be found (are you missing a using directive or an assembly reference?) [/Users/stack72/code/go/src/github.com/pulumi/pulumi-aws/sdk/dotnet/Pulumi.Aws.csproj]
```

* Fix the nullability of config type properties in C# codegen (#4379)
2020-04-14 09:30:25 +01:00
evanboyle ec686bbaf6 Merge branch 'master' of https://github.com/pulumi/pulumi into evan/gomod 2020-03-18 17:57:58 -07:00
evanboyle d3f5bbce48 go fmt 2020-03-18 17:27:02 -07:00
evanboyle 8df534a71e move pkg/diag -> sdk/go/common/diag 2020-03-18 15:09:29 -07:00
evanboyle fccf301d14 move pkg/util/contract -> sdk/go/common/util/contract 2020-03-18 14:40:07 -07:00
evanboyle fba783caf9 move pkg/resource -> sdk/go/common/resource, but leave nested resource packages 2020-03-18 13:36:19 -07:00
Justin Van Patten 1354b17eb3
PaC: Filter internal resource property keys (#4099)
Filter out internal resource properties like `__defaults` before passing to analyzers.
2020-03-18 11:39:13 -07:00
Pat Gavlin c383810bf8
Omit unknowns in resources in stack outputs during preview. (#3427)
If a stack output includes a `Resource`, we will as of a recent change
always show the output diff, but this diff will potentially include
unknowns, leading to spurious output like:

```
+ namePrefix : output<string>
```

These changes supress these diffs by adding a special key to the POJO
we generate for resources *during preview only* that indicates that the
POJO represents a Pulumi resource, then stripping all adds of unknown
values from diffs for objects marked with that key.

Fixes #3314.
2019-10-30 11:36:03 -07:00
CyrusNajmabadi 0ea50f458e
Print destroyed outputs when a stack is destroyed. (#3261) 2019-09-24 17:15:46 -07:00
CyrusNajmabadi 1387afec8f
Color 'reads' as cyan so they don't look like 'creates'. (#3236) 2019-09-18 09:49:13 -07:00
Pat Gavlin e1a52693dc
Add support for importing existing resources. (#2893)
A resource can be imported by setting the `import` property in the
resource options bag when instantiating a resource. In order to
successfully import a resource, its desired configuration (i.e. its
inputs) must not differ from its actual configuration (i.e. its state)
as calculated by the resource's provider.

There are a few interesting state transitions hiding here when importing
a resource:
1. No prior resource exists in the checkpoint file. In this case, the
   resource is simply imported.
2. An external resource exists in the checkpoint file. In this case, the
   resource is imported and the old external state is discarded.
3. A non-external resource exists in the checkpoint file and its ID is
   different from the ID to import. In this case, the new resource is
   imported and the old resource is deleted.
4. A non-external resource exists in the checkpoint file, but the ID is
   the same as the ID to import. In this case, the import ID is ignored
   and the resource is treated as it would be in all cases except for
   changes that would replace the resource. In that case, the step
   generator issues an error that indicates that the import ID should be
   removed: were we to move forward with the replace, the new state of
   the stack would fall under case (3), which is almost certainly not
   what the user intends.

Fixes #1662.
2019-07-12 11:12:01 -07:00
Pat Gavlin 6e5c4a38d8
Defer all diffs to resource providers. (#2849)
Thse changes make a subtle but critical adjustment to the process the
Pulumi engine uses to determine whether or not a difference exists
between a resource's actual and desired states, and adjusts the way this
difference is calculated and displayed accordingly.

Today, the Pulumi engine get the first chance to decide whether or not
there is a difference between a resource's actual and desired states. It
does this by comparing the current set of inputs for a resource (i.e.
the inputs from the running Pulumi program) with the last set of inputs
used to update the resource. If there is no difference between the old
and new inputs, the engine decides that no change is necessary without
consulting the resource's provider. Only if there are changes does the
engine consult the resource's provider for more information about the
difference. This can be problematic for a number of reasons:

- Not all providers do input-input comparison; some do input-state
  comparison
- Not all providers are able to update the last deployed set of inputs
  when performing a refresh
- Some providers--either intentionally or due to bugs--may see changes
  in resources whose inputs have not changed

All of these situations are confusing at the very least, and the first
is problematic with respect to correctness. Furthermore, the display
code only renders diffs it observes rather than rendering the diffs
observed by the provider, which can obscure the actual changes detected
at runtime.

These changes address both of these issues:
- Rather than comparing the current inputs against the last inputs
  before calling a resource provider's Diff function, the engine calls
  the Diff function in all cases.
- Providers may now return a list of properties that differ between the
  requested and actual state and the way in which they differ. This
  information will then be used by the CLI to render the diff
  appropriately. A provider may also indicate that a particular diff is
  between old and new inputs rather than old state and new inputs.

Fixes #2453.
2019-07-01 12:34:19 -07:00
James Nugent edab10e9c8 Use Go Modules for dependency tracking
This commit switches from dep to Go 1.12 modules for tracking Pulumi
dependencies. Rather than _building_ using Go modules, we instead use the `go
mod vendor` command to populate a vendor tree in the same way as `dep ensure`
was previously doing.

In order to prevent checksum mismatches, it was necessary to also update CI to
use Go 1.12 instead of 1.11 - which also necessitated fixing some linting errors
which appeared with the upgraded golangci-lint for 1.12.
2019-04-10 08:37:51 +04:00
Pat Gavlin d14f47b162
Elide diffs in internal properties (#2543)
Various providers use properties that begin with "__" to represent
internal metadata that should not be presented to the user. These
changes look for such properties and elide them when displaying diffs.
2019-03-11 18:01:48 -07:00
Pat Gavlin 7ebd70a3e6
Refresh inputs (#2531)
These changes take advantage of the newly-added support for returning
inputs from Read to update a resource's inputs as part of a refresh.
As a consequence, the Pulumi engine will now properly detect drift
between the actual state of a resource and the desired state described
by the program and generate appropriate update or replace steps.

As part of these changes, a resource's old inputs are now passed to the
provider when performing a refresh. The provider can take advantage of
this to maintain the accuracy of any additional data or metadata in the
resource's inputs that may need to be updated during the refresh.

This is required for the complete implementation of
https://github.com/pulumi/pulumi-terraform/pull/349. Without access to
the old inputs for a resource, TF-based providers would lose all
information about default population during a refresh.
2019-03-11 13:50:00 -07:00
Pat Gavlin 4b33a45561
Filter diff keys based on provider info (#2526)
If a provider returns information about the top-level properties that
differ, use those keys to filter the diffs that are rendered to the
user.

Fixes #2453.
2019-03-06 16:41:19 -08:00
Pat Gavlin 128afe3323
Use "discard" when deleting read resources (#2280)
In general, a "delete" in Pulumi is destroying an actual physical
resource. In the case of a read resource, however, the delete is
merely removing the resource from the stack; the physical resource
is not affected. These changes attempt to clarify this situation by
using the term "discard" rather than "delete".

Fixes #2015.
2019-01-31 13:48:44 -08:00
CyrusNajmabadi ca8169e344
Use 'output<...>' as our terminology for 'computed' properties. (#2267) 2018-12-02 19:44:50 -08:00
CyrusNajmabadi 16ae1f2a81
Fix rendering of the 'outputs:' header in the diff view. (#2020) 2018-10-03 13:06:20 -07:00
Sean Gillespie 6338875b72
Fix pulumi/pulumi#1995 (#1997)
The diff display code was not expecting that it would be possible for
resource properties to transition from being an archive to being an
asset, or the other way around. This commit prints out a reasonable diff
if this situation occurs instead of crashing.
2018-09-28 11:46:43 -07:00
joeduffy 3468393490 Make a smattering of CLI UX improvements
Since I was digging around over the weekend after the change to move
away from light black, and the impact it had on less important
information showing more prominently than it used to, I took a step
back and did a deeper tidying up of things. Another side goal of this
exercise was to be a little more respectful of terminal width; when
we could say things with fewer words, I did so.

* Stylize the preview/update summary differently, so that it stands
  out as a section. Also highlight the total changes with bold -- it
  turns out this has a similar effect to the bright white colorization,
  just without the negative effects on e.g. white terminals.

* Eliminate some verbosity in the phrasing of change summaries.

* Make all heading sections stylized consistently. This includes
  the color (bright magenta) and the vertical spacing (always a newline
  separating headings). We were previously inconsistent on this (e.g.,
  outputs were under "---outputs---"). Now   the headings are:
  Previewing (etc), Diagnostics, Outputs, Resources, Duration, and Permalink.

* Fix an issue where we'd parent things to "global" until the stack
  object later showed up. Now we'll simply mock up a stack resource.

* Don't show messages like "no change" or "unchanged". Prior to the
  light black removal, these faded into the background of the terminal.
  Now they just clutter up the display. Similar to the elision of "*"
  for OpSames in a prior commit, just leave these out. Now anything
  that's written is actually a meaningful status for the user to note.

* Don't show the "3 info messages," etc. summaries in the Info column
  while an update is ongoing. Instead, just show the latest line. This
  is more respectful of width -- I often find that the important
  messages scroll off the right of my screen before this change.

    For discussion:

        - I actually wonder if we should eliminate the summary
          altogether and always just show the latest line. Or even
          blank it out. The summary feels better suited for the
          Diagnostics section, and the Status concisely tells us
          how a resource's update ended up (failed, succeeded, etc).

        - Similarly, I question the idea of showing only the "worst"
          message. I'd vote for always showing the latest, and again
          leaving it to the Status column for concisely telling the
          user about the final state a resource ended up in.

* Stop prepending "info: " to every stdout/stderr message. It adds
  no value, clutters up the display, and worsens horizontal usage.

* Lessen the verbosity of update headline messages, so we now instead
  of e.g. "Previewing update of stack 'x':", we just say
  "Previewing update (x):".

* Eliminate vertical whitespace in the Diagnostics section. Every
  independent console.out previously was separated by an entire newline,
  which made the section look cluttered to my eyes. These are just
  streams of logs, there's no reason for the extra newlines.

* Colorize the resource headers in the Diagnostic section light blue.

Note that this will change various test baselines, which I will
update next. I didn't want those in the same commit.
2018-09-24 08:43:46 -07:00
Sean Gillespie 59098fb6b6
Clarify condition for displaying outputs (#1927) 2018-09-13 09:16:19 -07:00
Sean Gillespie 3d5f005c95
Fix several output-related issues (#1919)
* Revert "Don't show stack outputs when update fails (#1916)"

This reverts commit e3f89e82aa.

* Be more precise about printing outputs

This commit prints outputs only if they are known to be complete. This
avoids massive red diffs during previews and when component resources
fail to call registerResourceOutputs.

* CR: Clean up large boolean expression and comment

* CR: boolean compromise
2018-09-11 16:44:06 -07:00
Alex Clemmer 2fa98a8dad Generate empty update steps for partial failures
This commit will greatly improve the experience of dealing with partial
failures by simply re-trying to initialize the relevant resources on
every subsequent `pulumi up`, instead of printing a list of reasons the
resource had previously failed to initialize.

As motivation, consider our behavior in the following common, painful
scenario:

  * The user creates a `Service` and a `Deployment`.
  * The `Pod`s in the `Deployment` fail to become live. This causes the
    `Service` to fail, since it does not target any live `Pod`s.
  * The user fixes the `Deployment`. A run of `pulumi up` sees the
    `Pod`s successfully initialize.
  * Users will expect that the `Service` is now in a state of success,
    as the `Pod`s it targets are alive. But, because we don't update the
    `Service` by default, it perpetually exists in a state of error.
  * The user is now required to change some trivial feature of the
    `Service` just to trigger an update, so that we can see it succeed.

There are many situations like this. Another very common one is waiting
for test `Pod`s that are meant to successfully complete when some object
becomes live.

By triggering an empty update step for all resources that have any
initialization errors, we avoid all problems like this.

This commit will implement this empty-update semantics for partial
failures, as well as fix the display UX to correctly render the diff in
these cases.
2018-08-28 18:00:35 -07:00
Pat Gavlin abfdf69a9c
Indent stack outputs by 1. (#1822)
* Indent stack outputs by 1.

Also:
- Show stack output diffs during preview
- Fix a bug where deletes in stack outputs were not displayed
2018-08-24 15:36:55 -07:00
Pat Gavlin 73f4f2c464
Reimplement refresh. (#1814)
Replace the Source-based implementation of refresh with a phase that
runs as the first part of plan execution and rewrites the snapshot in-memory.

In order to fit neatly within the existing framework for resource operations,
these changes introduce a new kind of step, RefreshStep, to represent
refreshes. RefreshSteps operate similar to ReadSteps but do not imply that
the resource being read is not managed by Pulumi.

In addition to the refresh reimplementation, these changes incorporate those
from #1394 to run refresh in the integration test framework.

Fixes #1598.
Fixes pulumi/pulumi-terraform#165.
Contributes to #1449.
2018-08-22 17:52:46 -07:00
CyrusNajmabadi da616eccca
Print out an archive diff even in the event of resource replacement. (#1760) 2018-08-11 18:33:27 -07:00
Pat Gavlin e8697d872a
Elide events that refer to default providers. (#1739)
The belief is that this hides some complexity that we shouldn't be
exposing in the default case.

In order to filter these events from both the diff/progress display
and the resource change summary, we perform this filtering in
`pkg/engine`.

Fixes #1733.
2018-08-09 14:45:39 -07:00
CyrusNajmabadi b682777a1f
Don't print out unchanged assets while diffing an archive. (#1730) 2018-08-08 01:10:30 -04:00
Pat Gavlin a222705143
Implement first-class providers. (#1695)
### First-Class Providers
These changes implement support for first-class providers. First-class
providers are provider plugins that are exposed as resources via the
Pulumi programming model so that they may be explicitly and multiply
instantiated. Each instance of a provider resource may be configured
differently, and configuration parameters may be source from the
outputs of other resources.

### Provider Plugin Changes
In order to accommodate the need to verify and diff provider
configuration and configure providers without complete configuration
information, these changes adjust the high-level provider plugin
interface. Two new methods for validating a provider's configuration
and diffing changes to the same have been added (`CheckConfig` and
`DiffConfig`, respectively), and the type of the configuration bag
accepted by `Configure` has been changed to a `PropertyMap`.

These changes have not yet been reflected in the provider plugin gRPC
interface. We will do this in a set of follow-up changes. Until then,
these methods are implemented by adapters:
- `CheckConfig` validates that all configuration parameters are string
  or unknown properties. This is necessary because existing plugins
  only accept string-typed configuration values.
- `DiffConfig` either returns "never replace" if all configuration
  values are known or "must replace" if any configuration value is
  unknown. The justification for this behavior is given
  [here](https://github.com/pulumi/pulumi/pull/1695/files#diff-a6cd5c7f337665f5bb22e92ca5f07537R106)
- `Configure` converts the config bag to a legacy config map and
  configures the provider plugin if all config values are known. If any
  config value is unknown, the underlying plugin is not configured and
  the provider may only perform `Check`, `Read`, and `Invoke`, all of
  which return empty results. We justify this behavior becuase it is
  only possible during a preview and provides the best experience we
  can manage with the existing gRPC interface.

### Resource Model Changes
Providers are now exposed as resources that participate in a stack's
dependency graph. Like other resources, they are explicitly created,
may have multiple instances, and may have dependencies on other
resources. Providers are referred to using provider references, which
are a combination of the provider's URN and its ID. This design
addresses the need during a preview to refer to providers that have not
yet been physically created and therefore have no ID.

All custom resources that are not themselves providers must specify a
single provider via a provider reference. The named provider will be
used to manage that resource's CRUD operations. If a resource's
provider reference changes, the resource must be replaced. Though its
URN is not present in the resource's dependency list, the provider
should be treated as a dependency of the resource when topologically
sorting the dependency graph.

Finally, `Invoke` operations must now specify a provider to use for the
invocation via a provider reference.

### Engine Changes
First-class providers support requires a few changes to the engine:
- The engine must have some way to map from provider references to
  provider plugins. It must be possible to add providers from a stack's
  checkpoint to this map and to register new/updated providers during
  the execution of a plan in response to CRUD operations on provider
  resources.
- In order to support updating existing stacks using existing Pulumi
  programs that may not explicitly instantiate providers, the engine
  must be able to manage the "default" providers for each package
  referenced by a checkpoint or Pulumi program. The configuration for
  a "default" provider is taken from the stack's configuration data.

The former need is addressed by adding a provider registry type that is
responsible for managing all of the plugins required by a plan. In
addition to loading plugins froma checkpoint and providing the ability
to map from a provider reference to a provider plugin, this type serves
as the provider plugin for providers themselves (i.e. it is the
"provider provider").

The latter need is solved via two relatively self-contained changes to
plan setup and the eval source.

During plan setup, the old checkpoint is scanned for custom resources
that do not have a provider reference in order to compute the set of
packages that require a default provider. Once this set has been
computed, the required default provider definitions are conjured and
prepended to the checkpoint's resource list. Each resource that
requires a default provider is then updated to refer to the default
provider for its package.

While an eval source is running, each custom resource registration,
resource read, and invoke that does not name a provider is trapped
before being returned by the source iterator. If no default provider
for the appropriate package has been registered, the eval source
synthesizes an appropriate registration, waits for it to complete, and
records the registered provider's reference. This reference is injected
into the original request, which is then processed as usual. If a
default provider was already registered, the recorded reference is
used and no new registration occurs.

### SDK Changes
These changes only expose first-class providers from the Node.JS SDK.
- A new abstract class, `ProviderResource`, can be subclassed and used
  to instantiate first-class providers.
- A new field in `ResourceOptions`, `provider`, can be used to supply
  a particular provider instance to manage a `CustomResource`'s CRUD
  operations.
- A new type, `InvokeOptions`, can be used to specify options that
  control the behavior of a call to `pulumi.runtime.invoke`. This type
  includes a `provider` field that is analogous to
  `ResourceOptions.provider`.
2018-08-06 17:50:29 -07:00
joeduffy 5967259795 Add license headers 2018-05-22 15:02:47 -07:00
joeduffy b77403b4bb Implement a refresh command
This change implements a `pulumi refresh` command.  It operates a bit
like `pulumi update`, and friends, in that it supports `--preview` and
`--diff`, along with the usual flags, and will update your checkpoint.

It works through substitution of the deploy.Source abstraction, which
generates a sequence of resource registration events.  This new
deploy.RefreshSource takes in a prior checkpoint and will walk it,
refreshing the state via the associated resource providers by invoking
Read for each resource encountered, and merging the resulting state with
the prior checkpoint, to yield a new resource.Goal state.  This state is
then fed through the engine in the usual ways with a few minor caveats:
namely, although the engine must generate steps for the logical
operations (permitting us to get nice summaries, progress, and diffs),
it mustn't actually carry them out because the state being imported
already reflects reality (a deleted resource has *already* been deleted,
so of course the engine need not perform the deletion).  The diffing
logic also needs to know how to treat the case of refresh slightly
differently, because we are going to be diffing outputs and not inputs.

Note that support for managed stacks is not yet complete, since that
requires updates to the service to support a refresh endpoint.  That
will be coming soon ...
2018-04-18 10:57:16 -07:00
CyrusNajmabadi 50dafdae6a
Simplify the diff for primitive values. (#1212) 2018-04-17 01:51:53 -07:00
CyrusNajmabadi b4b11991a2
Remove unused param. (#1211) 2018-04-16 14:42:36 -07:00
CyrusNajmabadi f2b9bd4b13
Remove the explicit 'pulumi preview' command. (#1170)
Old command still exists, but tells you to run "pulumi update --preview".
2018-04-13 22:26:01 -07:00
CyrusNajmabadi 4b761f9fc1
Include richer information in events so that final display can flexibly chose how to present it. (#1088) 2018-03-31 12:08:48 -07:00
joeduffy 8b5874dab5 General prep work for refresh
This change includes a bunch of refactorings I made in prep for
doing refresh (first, the command, see pulumi/pulumi#1081):

* The primary change is to change the way the engine's core update
  functionality works with respect to deploy.Source.  This is the
  way we can plug in new sources of resource information during
  planning (and, soon, diffing).  The way I intend to model refresh
  is by having a new kind of source, deploy.RefreshSource, which
  will let us do virtually everything about an update/diff the same
  way with refreshes, which avoid otherwise duplicative effort.

  This includes changing the planOptions (nee deployOptions) to
  take a new SourceFunc callback, which is responsible for creating
  a source specific to the kind of plan being requested.

  Preview, Update, and Destroy now are primarily differentiated by
  the kind of deploy.Source that they return, rather than sprinkling
  things like `if Destroying` throughout.  This tidies up some logic
  and, more importantly, gives us precisely the refresh hook we need.

* Originally, we used the deploy.NullSource for Destroy operations.
  This simply returns nothing, which is how Destroy works.  For some
  reason, we were no longer doing this, and instead had some
  `if Destroying` cases sprinkled throughout the deploy.EvalSource.
  I think this is a vestige of some old way we did configuration, at
  least judging by a comment, which is apparently no longer relevant.

* Move diff and diff-printing logic within the engine into its own
  pkg/engine/diff.go file, to prepare for upcoming work.

* I keep noticing benign diffs anytime I regenerate protobufs.  I
  suspect this is because we're also on different versions.  I changed
  generate.sh to also dump the version into grpc_version.txt.  At
  least we can understand where the diffs are coming from, decide
  whether to take them (i.e., a newer version), and ensure that as
  a team we are monotonically increasing, and not going backwards.

* I also tidied up some tiny things I noticed while in there, like
  comments, incorrect types, lint suppressions, and so on.
2018-03-28 07:45:23 -07:00