Add sql output format (#235)

Author: bplunkett-stripe

cmd/pg-schema-diff/main_test.go

@@ -34,6 +34,8 @@ type runCmdWithAssertionsParams struct {
 	// saving schemas to a randomly generated temporary directory.
 	dynamicArgs []dArgGenerator
 
+	// outputEquals is the exact string that stdout should equal.
+	outputEquals string
 	// outputContains is a list of substrings that are expected to be contained in the stdout output of the command.
 	outputContains []string
 	// expectErrContains is a list of substrings that are expected to be contained in the error returned by
@@ -72,6 +74,9 @@ func (suite *cmdTestSuite) runCmdWithAssertions(tc runCmdWithAssertionsParams) {
 			suite.Contains(stdOutStr, o)
 		}
 	}
+	if len(tc.outputEquals) > 0 {
+		suite.Equal(tc.outputEquals, stdOutStr)
+	}
 }
 
 // dArgGenerator generates argument at the run-time of the test case...

cmd/pg-schema-diff/plan_cmd.go

@@ -172,9 +172,15 @@ var (
 		convertToOutputString: planToJsonS,
 	}
 
+	outputFormatSql = outputFormat{
+		identifier:            "sql",
+		convertToOutputString: planToSql,
+	}
+
 	outputFormats = []outputFormat{
 		outputFormatPretty,
 		outputFormatJson,
+		outputFormatSql,
 	}
 
 	outputFormatStrings = func() []string {
@@ -584,10 +590,30 @@ func hazardToPrettyS(hazard diff.MigrationHazard) string {
 	}
 }
 
+// planToJsonS converts the plan to JSON.
 func planToJsonS(plan diff.Plan) string {
 	jsonData, err := json.MarshalIndent(plan, "", "  ")
 	if err != nil {
 		panic(err)
 	}
 	return string(jsonData)
 }
+
+// planToSql converts the plan to one large runnable SQL script.
+func planToSql(plan diff.Plan) string {
+	sb := strings.Builder{}
+	for i, stmt := range plan.Statements {
+		if len(stmt.Hazards) > 0 {
+			for _, hazard := range stmt.Hazards {
+				sb.WriteString(fmt.Sprintf("-- Hazard %s\n", hazardToPrettyS(hazard)))
+			}
+		}
+		sb.WriteString(fmt.Sprintf("SET SESSION statement_timeout = %d;\n", stmt.Timeout.Milliseconds()))
+		sb.WriteString(fmt.Sprintf("SET SESSION lock_timeout = %d;\n", stmt.LockTimeout.Milliseconds()))
+		sb.WriteString(fmt.Sprintf("%s;", stmt.DDL))
+		if i < len(plan.Statements)-1 {
+			sb.WriteString("\n\n")
+		}
+	}
+	return sb.String()
+}

cmd/pg-schema-diff/plan_cmd_test.go

@@ -12,6 +12,8 @@ func (suite *cmdTestSuite) TestPlanCmd() {
 		args        []string
 		dynamicArgs []dArgGenerator
 
+		// outputEquals is the exact string that stdout should equal.
+		outputEquals string
 		// outputContains is a list of substrings that are expected to be contained in the stdout output of the command.
 		outputContains []string
 		// expectErrContains is a list of substrings that are expected to be contained in the error returned by
@@ -91,11 +93,43 @@ func (suite *cmdTestSuite) TestPlanCmd() {
 			args:              []string{"--from-dir", "some-dir", "--to-dir", "some-other-dir"},
 			expectErrContains: []string{"at least one Postgres server"},
 		},
+		{
+			name: "sql output format",
+			args: []string{"--output-format", "sql"},
+			dynamicArgs: []dArgGenerator{
+				tempDsnDArg(suite.pgEngine, "temp-db-dsn", []string{""}),
+				tempSchemaDirDArg("from-dir", []string{`
+						CREATE TABLE foobar(
+							bar TEXT,
+							fizzbuzz TEXT
+						);
+				`}),
+				tempSchemaDirDArg("to-dir", []string{`
+						CREATE TABLE foobar(
+							bar TEXT,
+							fizzbuzz TEXT
+						);
+					CREATE INDEX bar_idx ON foobar(bar);
+					CREATE INDEX fizzbuzz_idx ON foobar(fizzbuzz);
+				`}),
+			},
+			outputEquals: "-- Hazard INDEX_BUILD: This might affect database performance. Concurrent index builds require a non-trivial amount of CPU, potentially affecting database performance. They also can take a while but do not lock out writes.\nSET SESSION statement_timeout = 1200000;\nSET SESSION lock_timeout = 3000;\nCREATE INDEX CONCURRENTLY bar_idx ON public.foobar USING btree (bar);\n\n-- Hazard INDEX_BUILD: This might affect database performance. Concurrent index builds require a non-trivial amount of CPU, potentially affecting database performance. They also can take a while but do not lock out writes.\nSET SESSION statement_timeout = 1200000;\nSET SESSION lock_timeout = 3000;\nCREATE INDEX CONCURRENTLY fizzbuzz_idx ON public.foobar USING btree (fizzbuzz);\n",
+		},
+		{
+			name: "invalid output format",
+			args: []string{"--output-format", "invalid"},
+			dynamicArgs: []dArgGenerator{
+				tempDsnDArg(suite.pgEngine, "from-dsn", nil),
+				tempDsnDArg(suite.pgEngine, "to-dsn", []string{"CREATE TABLE foobar()"}),
+			},
+			expectErrContains: []string{"invalid output format"},
+		},
 	} {
 		suite.Run(tc.name, func() {
 			suite.runCmdWithAssertions(runCmdWithAssertionsParams{
 				args:              append([]string{"plan"}, tc.args...),
 				dynamicArgs:       tc.dynamicArgs,
+				outputEquals:      tc.outputEquals,
 				outputContains:    tc.outputContains,
 				expectErrContains: tc.expectErrContains,
 			})